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Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.717]   [H-I: 80]   [17 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [3031 journals]
  • Elucidation of penetration enhancement mechanism of Emu oil using FTIR
           microspectroscopy at EMIRA laboratory of SESAME synchrotron
    • Authors: Randa S.H. Mansour; Alsayed A. Sallam; Imad I. Hamdan; Enam A. Khalil; Ibraheem Yousef
      Pages: 1 - 10
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Randa S.H. Mansour, Alsayed A. Sallam, Imad I. Hamdan, Enam A. Khalil, Ibraheem Yousef
      It has been proposed that Emu oil possesses skin permeation-enhancing effect. This study aimed to address its possible penetration enhancement mechanism(s) using IR microscopy, in accordance with LPP theory. The penetration of Emu oil through the layers of human skin was accomplished by monitoring oil-IR characteristic feature at 3006cm−1. The unsaturated components of Emu oil accumulated at about 270μm depth of skin surface. The interaction of Emu oil with lipid and protein constituents of SC was investigated in comparison with a commonly used enhancer, IPM. Inter-sample spectral differences were identified using PCA and linked with possible enhancement mechanisms. Emu oil treatment caused a change in the slope of the right contour of amide I band of the protein spectral range. This was also clear in the second derivative spectra where the emergence of a new shoulder at higher frequency was evident, suggesting disorganization of keratin α-helix structure. This effect could be a result of disruption of some hydrogen bonds in which amide CO and NH groups of keratin are involved. The low intensity of the emerged shoulder is also in agreement with formation of weaker hydrogen bonds. IPM did not affect the protein component. No conclusions regarding the effect of penetration enhancers on the SC lipids were obtained. This was due to the overlap of the endogenous (skin) and exogenous (oil) CH stretching and scissoring frequencies. The SC carbonyl stretching peak disappeared as a result of IPM treatment which may reflect some degree of lipid extraction.
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      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.026
      Issue No: Vol. 185 (2017)
       
  • Citrus maxima (Pomelo) juice mediated eco-friendly synthesis of ZnO
           nanoparticles: Applications to photocatalytic, electrochemical sensor and
           antibacterial activities
    • Authors: N.S. Pavithra; K. Lingaraju; G.K. Raghu; G. Nagaraju
      Pages: 11 - 19
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): N.S. Pavithra, K. Lingaraju, G.K. Raghu, G. Nagaraju
      In the present work, Zinc oxide nanoparticles (ZnO Nps) have been successfully prepared through a simple, effective and low cost solution combustion method using Zn (NO3)2·6H2O as an oxidizer, chakkota (Common name=Pomelo) fruit juice as novel fuel. X-ray diffraction pattern indicates the hexagonal wurtzite structure with average crystallite size of ~22nm. ZnO Nps were characterized with the aid of different spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Photoluminescence and UV–Visible spectroscopy. FTIR shows characteristic ZnO vibrational mode at 393cm−1. SEM images show that the particles are agglomerated. TEM image shows the size of the particles are about 10–20nm. Further, in order to establish practical applicability of the synthesized ZnO Nps, photocatalytic degradation of methylene blue (MB) dye as a model system was studied in presence of UV (665nm) light. In addition to this, the antibacterial activity was screen against 3 bacterial strains and electrochemical sensor performance towards the quantification of dopamine at nano molar concentrations was also explored.
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      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.032
      Issue No: Vol. 185 (2017)
       
  • Synthesis, characterization, and nonlinear optical (NLO) properties of
           truxene-cored diphenylamine derivatives
    • Authors: Fusheng Li; Baodong Zhao; Yu Chen; Yufei Zhang; Tao Wang; Song Xue
      Pages: 20 - 26
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Fusheng Li, Baodong Zhao, Yu Chen, Yufei Zhang, Tao Wang, Song Xue
      Three star-shaped compounds based on a truxene core (FS11, FS12 and FS13) were prepared. The truxene core is incorporating with asymmetric diphenylamines, including one phenyl of diphenylamine substituted by methoxy group and the other phenyl substituted by tolyl, fluorophenyl and phenylethynyl for FS11, FS12 and FS13, respectively. Their one-photon, two-photon absorption, geometric structures, electrochemical behavior and thermal properties were investigated. The absorption maxima of charge transfer band for FS11, FS12 and FS13 are 375nm, 373nm and 383nm, and the corresponding molar extinction coefficients of FS11, FS12 and FS13 is 79,950M−1 cm−1, 67,220M−1 cm−1 and 108,780M−1 cm−1. The “pull-push” structure promotes charge transfer between asymmetric diphenylamine branches and the truxene core. Their two-photon absorbtion property is measured by two-photon induced fluorescence. The maximum two-photon cross-sections values of FS11, FS12 and FS13 are excited at 750nm, which are 260 GM, 204GM and 367 GM, respectively.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.030
      Issue No: Vol. 185 (2017)
       
  • Colorimetric detection of biothiols based on aggregation of
           chitosan-stabilized silver nanoparticles
    • Authors: Somayeh Mohammadi; Gholamreza Khayatian
      Pages: 27 - 34
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Somayeh Mohammadi, Gholamreza Khayatian
      We have described a simple and reliable colorimetric method for the sensing of biothiols such as cysteine, homocysteine, and glutathione in biological samples. The selective binding of chitosan capped silver nanoparticles to biothiols induced aggregation of the chitosan–Ag NPs. But the other amino acids that do not have thiol group cannot aggregate the chitosan–Ag NPs. Aggregation of chitosan–Ag NPs has been confirmed with UV–vis absorption spectra, zeta potential and transmission electron microscopy images. Under optimum conditions, good linear relationships existed between the absorption ratios (at A500/A415) and the concentrations of cysteine, homocysteine, and glutathione in the range of 0.1–10.0μM with detection limits of 15.0, 84.6 and 40.0nM, respectively. This probe was successfully applied to detect these biothiols in biological samples (urine and plasma).
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.034
      Issue No: Vol. 185 (2017)
       
  • Spectra-structure correlations of saturated and unsaturated medium-chain
           fatty acids. Near-infrared and anharmonic DFT study of hexanoic acid and
           sorbic acid
    • Authors: Justyna Grabska; Krzysztof B. Beć; Mika Ishigaki; Marek J. Wójcik; Yukihiro Ozaki
      Pages: 35 - 44
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Justyna Grabska, Krzysztof B. Beć, Mika Ishigaki, Marek J. Wójcik, Yukihiro Ozaki
      Quantum chemical reproduction of entire NIR spectra is a new trend, enabled by contemporary advances in the anharmonic approaches. At the same time, recent increase of the importance of NIR spectroscopy of biological samples raises high demand for gaining deeper understanding of NIR spectra of biomolecules, i.e. fatty acids. In this work we investigate saturated and unsaturated medium-chain fatty acids, hexanoic acid and sorbic acid, in the near-infrared region. By employing fully anharmonic density functional theory (DFT) calculations we reproduce the experimental NIR spectra of these systems, including the highly specific spectral features corresponding to the dimerization of fatty acids. Broad range of concentration levels from 5·10−4 M in CCl4 to pure samples are investigated. The major role of cyclic dimers can be evidenced for the vast majority of these samples. A highly specific NIR feature of fatty acids, the elevation of spectral baseline around 6500–4000cm−1, is being explained by the contributions of combination bands resulting from the vibrations of hydrogen-bonded OH groups in the cyclic dimers. Based on the high agreement between the calculated and experimental NIR spectra, a detailed NIR band assignments are proposed for hexanoic acid and sorbic acid. Subsequently, the correlations between the structure and NIR spectra are elucidated, emphasizing the regions in which clear and universal traces of specific bands corresponding to saturated and unsaturated alkyl chains can be established, thus demonstrating the wavenumber regions highly valuable for structural identifications.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.024
      Issue No: Vol. 185 (2017)
       
  • A synchrotron infrared absorption study of pressure induced polymerization
           of acrylamide
    • Authors: Himal Bhatt; M.N. Deo
      Pages: 45 - 51
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Himal Bhatt, M.N. Deo
      The hydrogen bonded dimeric structure of the model amide based molecular crystal acrylamide has been investigated under pressure using micro-spectroscopy, employing synchrotron infrared radiation up to 24GPa at room temperature. The high pressure spectra indicate systematic evolution of new features above 4GPa, which have been identified to be due to the emergence of a polymeric phase. The polymerization gets completed up to 16.8GPa and the observed changes are found to be irreversible upon the release of pressure. The behavior of NH stretching modes indicate that the uniform inter- and intra-dimeric interactions, rather than depicting a drastic reconstruction across the phase transition, show subtle modifications and become diverse in the high pressure polymeric phase.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.04.083
      Issue No: Vol. 185 (2017)
       
  • Raman spectroscopic study of cyclohexane at pressures below 1000MPa
    • Authors: Erwei Qiao; Haifei Zheng
      Pages: 52 - 54
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Erwei Qiao, Haifei Zheng
      At present, the room temperature freezing pressure of cyclohexane is still uncertain, and the phase transition pressure of solid I - solid III is not reliable at ambient temperature. In this work, we have performed a Raman spectroscopic study of cyclohexane in a Moissanite anvil cell at pressures below 1000MPa at 25°C, and analyzed the characteristic of Raman brands ν s(CH2), ν as(CH2) and ν b(Ring). Two phase transition pressures 80MPa and 550MPa were determined by a quartz pressure gauge, and they are the room temperature freezing pressure of cyclohexane and the phase transition pressure of solid I to solid III, respectively. Furthermore, from the phase diagram of cyclohexane, it is inferred that pressure plays an important role on the stability of cyclohexane as the main constituent of oil, and it can be beneficial to understanding the formation, migration and preservation of petroleum in subterranean rock strata.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.033
      Issue No: Vol. 185 (2017)
       
  • Assessment of hyperspectral imaging system for colour measurement
    • Authors: Damian K. Chlebda; Anna Rogulska; Tomasz Łojewski
      Pages: 55 - 62
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Damian K. Chlebda, Anna Rogulska, Tomasz Łojewski
      A novel technique of reflective spectroscopy, hyperspectral imaging (HSI), was used to develop a methodology for colour measurement, which is very important in the field of art conservation – especially in the analysis of documents. The major focus of this work is an examination of the repeatability and reproducibility of colour parameters calculated from the hyperspectral data. The study was performed with commercial colour standards and pen ink lines, corresponding to large and small-scale colour areas, respectively. In some cases, the error of parameter determination indicated significant differences between the examined sample sets, which may be attributed to the low population of pixels from which the colour data were obtained. Our study allowed the development of an optimal hyperspectral image acquisition method for applications requiring accurate determination of the object's spectral characteristics. Besides determining the proper measurement procedure and the colour accuracy of the HSI, our study is also used to test this method for colour change monitoring of a real-life sample – a document treated with low-temperature plasma as a cleaning agent. The results proved that, by using hyperspectral imaging, colour change can be precisely determined and monitored within a selected area on the object. The application of HSI presented in our study was found to be an important alternative to conventional colorimeters.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.037
      Issue No: Vol. 185 (2017)
       
  • Vibrational spectroscopy of the mass-selected tetrahydrofurfuryl alcohol
           monomers and its dimers in gas phase using IR depletion and VUV single
           photon ionization
    • Authors: Pengchao Wang; Yongjun Hu; Huaqi Zhan; Jiaxin Chen; Shan Jin; Wentao Song; Yujian Li
      Pages: 63 - 68
      Abstract: Publication date: 5 October 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 185
      Author(s): Pengchao Wang, Yongjun Hu, Huaqi Zhan, Jiaxin Chen, Shan Jin, Wentao Song, Yujian Li
      Tetrahydrofurfuryl alcohol (THFA, C5H10O2) is a close chemical analog of the sugar rings present in the phosphate-deoxyribose backbone structure of the nucleic acids. In present report, the infrared (IR) spectra of the size-selected THFA monomer and its dimer have been investigated in a pulsed supersonic jet using infrared-vacuum ultraviolet (VUV) ionization. Herein, the laser light at 118nm wavelength served as the source of “soft” ionization in a time-of-flight mass spectrometer. The IR features for the monomers located at 3622cm−1 can be assigned to the intramolecular hydrogen bonding stretch vibrations mainly referring to A and C conformers. Compared with the monomer, however, characteristic peaks for the dimer centered at 3415 and 3453cm−1, red shifted 207 and 169cm−1, respectively, were associated with the intermolecular hydrogen bonding stretch vibrations. Combined with the quantum-chemical calculations, the dimer in the gas phase preferred cyclic AC conformer stabled by forming two strong intermolecular hydrogen bonds, which shown the high hydrogen bond selectivity in the cluster. The conclusions drawn from the role played in the conformational flexibility by the hydroxyl and ether groups may be extended to other biomolecules.
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      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.04.089
      Issue No: Vol. 185 (2017)
       
  • Depth profiling of APTES self-assembled monolayers using surface-enhanced
           confocal Raman microspectroscopy
    • Authors: Yingying Sun; Masahiro Yanagisawa; Masahiro Kunimoto; Masatoshi Nakamura; Takayuki Homma
      Pages: 1 - 6
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Yingying Sun, Masahiro Yanagisawa, Masahiro Kunimoto, Masatoshi Nakamura, Takayuki Homma
      The internal structure of self-assembled monolayers (SAMs) such as 3-aminopropyltriethoxysilane (APTES) fabricated on a glass substrate is difficult to characterize and analyze at nanometer level. In this study, we employed surface-enhanced Raman spectroscopy (SERS) to study the internal molecular structure of APTES SAMs. The sample APTES SAMs were deposited with Ag nanoparticles to enhance the Raman signal and to obtain subtler structure information, which were supported by density functional theory calculations. In addition, in order to carry out high-resolution analysis, especially for vertical direction, a fine piezo electric positioner was used to control the depth scanning with a step of 0.1nm. We measured and distinguished the vertical Raman intensity variations of specific groups in APTES, such as Ag/NH2, CH2, and SiO, with high resolution. The interfacial bond at the two interfaces of Ag-APTES and APTES-SiO2 was identified. Moreover, APTES molecule orientation was demonstrated to be inhomogeneous from frequency shift.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.036
      Issue No: Vol. 184 (2017)
       
  • A turn-on type stimuli-responsive fluorescent dye with specific solvent
           effect: Implication for a new prototype of paper using water as the ink
    • Authors: Xiaochen Hu; Yang Liu; Yuai Duan; Jingqi Han; Zhongfeng Li; Tianyu Han
      Pages: 7 - 12
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Xiaochen Hu, Yang Liu, Yuai Duan, Jingqi Han, Zhongfeng Li, Tianyu Han
      In this study, we reported the photoluminescence (PL) behaviour of a new intramolecular charge transfer (ICT) compound, ((E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzoic acid, (HABA), which shows ICT solvent effect in aprotic solvents as confirmed by absorption and emission spectra. While in protic solvents including water and ethanol, the charge transfer (CT) band significantly reduces. Remarkable fluorescence enhancement in the blue region was also observed for HABA in polar protic solvents. We described such phenomena as “specific solvent effect”. It can be ascribed to the hydrogen bonding formation between HABA and protic solvents, which not only causes significant reduction in the rate of internal conversion but also elevates the energy gap. Density functional theory (DFT) calculations as well as the dynamics analysis were performed to further verify the existence of hydrogen bonding complexes. Stronger emission turn-on effect was observed on HABA solid film when it is treated with water and base solution. The stimuli-responsive fluorescence of HABA enables a new green printing technique that uses water/base as the ink, affording fluorescent handwritings highly distinct from the background. Thermoanalysis of the dye suggests the nice thermostability, which is highly desired for real-world printing in a wide temperature range.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.079
      Issue No: Vol. 184 (2017)
       
  • The influence of high fat diets with different ketogenic ratios on the
           hippocampal accumulation of creatine – FTIR microspectroscopy study
    • Authors: A. Skoczen; Z. Setkowicz; K. Janeczko; Ch. Sandt; F. Borondics; J. Chwiej
      Pages: 13 - 22
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): A. Skoczen, Z. Setkowicz, K. Janeczko, Ch. Sandt, F. Borondics, J. Chwiej
      The main purpose of this study was the determination and comparison of anomalies in creatine (Cr) accumulation occurring within CA3 and DG areas of hippocampal formation as a result of two high-fat, carbohydrate-restricted ketogenic diets (KD) with different ketogenic ratio (KR). To reach this goal, Fourier transformed infrared microspectroscopy with synchrotron radiation source (SRFTIR microspectroscopy) was applied for chemical mapping of creatine absorption bands, occurring around 1304, 1398 and 2800 cm−1. The samples were taken from three groups of experimental animals: control group (N) fed with standard laboratory diet, KD1 and KD2 groups fed with high-fat diets with KR 5:1 and 9:1 respectively. Additionally, the possible influence on the phosphocreatine (PhCr, the high energetic form of creatine) content was evaluated by comparative analysis of chemical maps obtained for creatine and for compounds containing phosphate groups which manifest in the spectra at the wavenumbers of around 1240 and 1080 cm−1. Our results showed that KD2 strongly modifies the frequency of Cr inclusions in both analyzed hippocampal areas. Statistical analysis, performed with Mann-Whitney U test revealed increased accumulation of Cr within CA3 and DG areas of KD2 fed rats compared to both normal rats and KD1 experimental group. Moreover, KD2 diet may modify the frequency of PhCr deposits as well as the PhCr to Cr ratio.
      Graphical abstract image

      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.085
      Issue No: Vol. 184 (2017)
       
  • Vibrational analysis of dibenzo-18-crown-6. Effect of dispersion
           correction on the calculated vibrational spectra
    • Authors: Nada A. Al-Jallal; Adel A. El-Azhary
      Pages: 23 - 29
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Nada A. Al-Jallal, Adel A. El-Azhary
      We report for the first time a detailed vibrational analysis of dibenzo-18-crown-6, db18c6. The experimental IR and Raman spectra of db18c6 were measured. The assignment of the fundamental vibrational frequencies of db18c6 was aided by using scaled quantum mechanical force fields calculated at the B3LYP/6-311G** and CAM-B3LYP/6-311G** levels. Comparison between the experimental and calculated spectra of some of the important conformations of db18c6 led to the conclusion that db18c6 in the solid phase exists in a C 2 conformation that is similar to that predicted by X-ray, for also the solid phase. The effect of inclusion of the atom pair-wise dispersion correction to the B3LYP method, known as the B3LYP-D3 method, on the calculated IR and Raman spectra of db18c6 at the B3LYP level was also investigated. It was concluded that the effect of inclusion of the dispersion correction on the calculated vibrational frequencies and intensities is negligible.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.069
      Issue No: Vol. 184 (2017)
       
  • Luminescence of ferrocene-modified pyrene derivatives for turn-on sensing
           of Cu2+ and anions
    • Authors: Shuhua Sun; Wenting Hu; Hongfang Gao; Honglan Qi; Liping Ding
      Pages: 30 - 37
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Shuhua Sun, Wenting Hu, Hongfang Gao, Honglan Qi, Liping Ding
      Detection and identification of metal ions by fluorescent turn-on sensors are challenging due to the quenching effect of most of the tested metal ions. In the present work, three ferrocene-modified pyrene-based probes 2–4 were synthesized to act as turn-on fluorescent sensors for Cu2+. The measurements of fluorescence quantum yield and fluorescence lifetime reveal that ferrocenyl unit can efficiently reduce the fluorescence emission of pyrene moiety. Steady-state fluorescence measurements find that the three ferrocene-modified fluorophores exhibit selective turn-on responses to Cu2+. Moreover, this turn-on effect to Cu2+ is highly influenced by the type of the counter ion. It is found that the presence of Cl− or NO3 − could realize the turn-on response to Cu2+, whereas, the presence of SO4 2− or Ac− could not induce any fluorescence enhancement to Cu2+. Control experiments with ferrocene-free pyrene-based probe 1 reveal that the ferrocenyl unit plays the key role in the turn-on response to Cu2+. The possible mechanism for the turn-on responses is attributed to the oxidation behavior of Cu2+ to the ferrocene unit, which is confirmed by the control experiments with sodium ascorbate. Cyclic voltammetry measurements show that Cu2+ can influence the redox behaviors of ferrocenyl derivatives, which is also highly dependent on the anion of the copper salts. The influence of anion on the turn-on responses to Cu2+ was further used for anion detection and fluorescent logic gate.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.073
      Issue No: Vol. 184 (2017)
       
  • Crystal structure, vibrational spectra, optical and DFT studies of bis
           (3-azaniumylpropyl) azanium pentachloroantimonate (III) chloride
           monohydrate (C6H20N3)SbCl5·Cl·H2O
    • Authors: Houssem Eddine Ahmed; Slaheddine Kamoun
      Pages: 38 - 46
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Houssem Eddine Ahmed, Slaheddine Kamoun
      The crystal structure of (C6H20N3)SbCl5·Cl·H2O is built up of [NH3(CH2)3NH2(CH2)3NH3]3+ cations, [SbCl5]2− anions, free Cl− anions and neutral water molecules connected together by NH⋯Cl, NH⋯O and OH⋯Cl hydrogen bonds. The optical band gap determined by diffuse reflection spectroscopy (DRS) is 3.78eV for a direct allowed transition. Optimized molecular geometry, atomic Mulliken charges, harmonic vibrational frequencies, HOMO–LUMO and related molecular properties of the (C6H20N3)SbCl5·Cl·H2O compound were calculated by Density functional theory (DFT) using B3LYP method with GenECP sets. The calculated structural parameters (bond lengths and angles) are in good agreement with the experimental XRD data. The vibrational unscaled wavenumbers were calculated and scaled by a proper scaling factor of 0.984. Acceptable consistency was observed between calculated and experimental results. The assignments of wavenumbers were made on the basis of potential energy distribution (PED) using Vibrational Energy Distribution Analysis (VEDA) software. The HOMO–LUMO study was extended to calculate various molecular parameters like ionization potential, electron affinity, global hardness, electro-chemical potential, electronegativity and global electrophilicity of the given molecule.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.059
      Issue No: Vol. 184 (2017)
       
  • Sensitive inexpensive spectrophotometric and spectrofluorimetric analysis
           of ezogabine, levetiracetam and topiramate in tablet formulations using
           Hantzsch condensation reaction
    • Authors: F.A. Ibrahim; A.F. El-Yazbi; M.M. Wagih; M.A. Barary
      Pages: 47 - 60
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): F.A. Ibrahim, A.F. El-Yazbi, M.M. Wagih, M.A. Barary
      Two highly sensitive, simple and selective spectrophotometric and spectrofluorimetric assays have been investigated for the analysis of ezogabine, levetiracetam and topiramate in their pure and in pharmaceutical dosage forms. The suggested methods depend on the condensation of the primary amino-groups in the three drugs with acetylacetone and formaldehyde according to Hantzsch reaction yielding highly fluorescent yellow colored dihydropyridine derivatives. The reaction products of ezogabine, levetiracetam and topiramate were measured spectrophotometrically at 418, 390 and 380nm or spectrofluorimetrically at λem / ex of 495/425nm, 490/415nm and 488/410nm, respectively. Various experimental conditions have been carefully studied to maximize the reaction yield. At the optimum reaction conditions, the calibration curves were rectilinear over the concentration ranges of 8–25, 60–180 and 80–200μg/mL spectrophotometrically and 0.02–0.2, 0.2–1.2 and 0.2–1.5μg/mL spectrofluorimetrically for ezogabine, levetiracetam and topiramate, respectively with good correlation coefficients. The suggested methods were applied successfully for the analysis of ezogabine, levetiracetam and topiramate in their commercial tablets with high percentage recoveries and negligible interference from various excipients in pharmaceutical dosage forms. The results were statistically analyzed and showed the absence of any significant difference between both developed and published methods. The procedures were validated and evaluated by the ICH guidelines revealing good reproducibility and accuracy. Therefore, the two proposed methods may be considered of high interest for practical and reliable analysis of ezogabine, levetiracetam and topiramate in pharmaceutical dosage forms.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.078
      Issue No: Vol. 184 (2017)
       
  • Evaluation of graphical and statistical representation of analytical
           signals of spectrophotometric methods
    • Authors: Hayam Mahmoud Lotfy; Yasmin Mohammed Fayez; Shereen Mostafa Tawakkol; Nesma Mahmoud Fahmy; Mostafa Abd El-Atty Shehata
      Pages: 61 - 70
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Hayam Mahmoud Lotfy, Yasmin Mohammed Fayez, Shereen Mostafa Tawakkol, Nesma Mahmoud Fahmy, Mostafa Abd El-Atty Shehata
      Simultaneous determination of miconazole (MIC), mometasone furaoate (MF), and gentamicin (GEN) in their pharmaceutical combination. Gentamicin determination is based on derivatization with of o-phthalaldehyde reagent (OPA) without any interference of other cited drugs, while the spectra of MIC and MF are resolved using both successive and progressive resolution techniques. The first derivative spectrum of MF is measured using constant multiplication or spectrum subtraction, while its recovered zero order spectrum is obtained using derivative transformation. Beside the application of constant value method. Zero order spectrum of MIC is obtained by derivative transformation after getting its first derivative spectrum by derivative subtraction method. The novel method namely, differential amplitude modulation is used to get the concentration of MF and MIC, while the novel graphical method namely, concentration value is used to get the concentration of MIC, MF, and GEN. Accuracy and precision testing of the developed methods show good results. Specificity of the methods is ensured and is successfully applied for the analysis of pharmaceutical formulation of the three drugs in combination. ICH guidelines are used for validation of the proposed methods. Statistical data are calculated, and the results are satisfactory revealing no significant difference regarding accuracy and precision.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.058
      Issue No: Vol. 184 (2017)
       
  • An enhancement of photoluminescence property of Ag doped La2O3 thin films
           at room temperature
    • Authors: R. Jbeli; A. Boukhachem; I. Ben Jemaa; N. Mahdhi; F. Saadallah; H. Elhouichet; S. Alleg; M. Amlouk; H. Ezzaouïa
      Pages: 71 - 81
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): R. Jbeli, A. Boukhachem, I. Ben Jemaa, N. Mahdhi, F. Saadallah, H. Elhouichet, S. Alleg, M. Amlouk, H. Ezzaouïa
      Metal transition doped oxide thin films or nanocomposites have recently emerged at the forefront of potentials research. With the focus mainly on efficiency, the aspect of stability against optical irradiation of such materials has so far not been thoroughly addressed. This work covers the synthesis of silver doped lanthanum oxide thin films (La2O3:Ag) which have been prepared by the spray pyrolysis technique on glass substrates at 460°C. Then, Ag thin films were grown on lanthanum oxide thin films by thermal evaporation. The present work aims to reach the synthesis of La2O3:Ag thin films using both the spray pyrolysis and thermal evaporation techniques. First, X-ray diffraction analysis shows that undoped and Ag doped films crystallize in a mixture of hexagonal and cubic phase with crystallites oriented along (001) direction. Raman spectroscopy shows the bands positions corresponding to hexagonal and cubic phases. On the other hand, an attempt regarding their optical properties has been carried out by means of photoluminescence measurements. Second, from electrical conductivity measurements, the activation energy decreases from 1.42 to 1.09eV with the increase of annealing time and the charge carriers are following the CBH model as dominant charge transport mechanism. Finally, the annealing time influences the surface wettability property and transforms La2O3 character from hydrophobic (θ>90°) to hydrophilic (θ<90°).
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.072
      Issue No: Vol. 184 (2017)
       
  • Properties of electronically excited states of four squaraine dyes and
           their complexes with fullerene C70: A theoretical investigation
    • Authors: Jian Zhang; Tingyu Li
      Pages: 82 - 88
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Jian Zhang, Tingyu Li
      Solar cells sensitized by polypyridyl Ru(II) complexes exhibit relatively high efficiency, however those photo-sensitizers did not absorb the photons in the far-red and near-infrared region. At present, squaraine dyes have received considerable attention as their attractively intrinsic red light absorption and unusual high molar extinction coefficient. Here we applied density functional theory and time dependent density functional theory to investigate the properties of electronically excited states of four squaraine dyes and their complexes with fullerene C70. The influences of different functionals, basis sets and solvent effects are evaluated. To understand the photophysical properties, the investigations are basing on a classification method which splits the squaraine dyes and their complexes with fullerene C70 into two units to characterize the intramolecular density distribution. We present the signatures of their electronically excited states which are characterized as local excitation or charge-transfer excitation. The relationship between open-circuit voltage and the number of intramolecular hydrogen bonds in squaraine dyes are discussed.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.086
      Issue No: Vol. 184 (2017)
       
  • Blue light emitting Y2O3:Tm3+ nanophosphors with tunable morphology
           obtained by bio-surfactant assisted sonochemical route
    • Authors: K.N. Venkatachalaiah; H. Nagabhushana; G.P. Darshan; R.B. Basavaraj; B. Daruka Prasad; S.C. Sharma
      Pages: 89 - 100
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): K.N. Venkatachalaiah, H. Nagabhushana, G.P. Darshan, R.B. Basavaraj, B. Daruka Prasad, S.C. Sharma
      Modified sonochemical route was used to prepare Y2O3:Tm3+ (1–11mol%) nanophosphor using Mimosa pudica (M.P.) leaves extract as bio-surfactant. The prepared samples were exhibited high crystalline nature with various morphologies. This was due to sonochemical experimental reaction took place between cavitation bubbles and nearby solution. The average crystallite sizes of the prepared samples were about 15nm to 21nm as obtained from PXRD and TEM analysis. The ultraviolet visible absorption spectra showed prominent bands with an energy gap varied from 5.73eV to 5.84eV. Photoluminescence (PL) emission spectra shows the prominent blue light emission peak at ~456nm attributed to 1D2 → 3F4 transitions of Tm3+ ions. Judd–Ofelt intensity parameters were estimated by using PL emission spectra. The photometric characteristics of the prepared compounds were very close to the blue color of NTSC standards. So the results were fruitful in making use of Y2O3:Tm3+ nanophosphor as an alternative material for effective blue component in WLED's.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.033
      Issue No: Vol. 184 (2017)
       
  • Novel spectrofluorimetric method for boldine alkaloid determination in
           herbal drugs and phytopharmaceuticals
    • Authors: Cecilia M. Peralta; Cecilia Henestrosa; Raúl A. Gil; Liliana P. Fernández; Gimena Acosta
      Pages: 101 - 108
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Cecilia M. Peralta, Cecilia Henestrosa, Raúl A. Gil, Liliana P. Fernández, Gimena Acosta
      A new green on-line method for Boldine determination (BOL) in herbal drugs and phytopharmaceuticals, using its native fluorescence in acid media (λex =282nm; λem =373nm) has been developed. The presented methodology involves for the first time, a flow injection (FI) strategy using a mini-column of multiwalled carbon nanotubes as retention agent coupled with molecular fluorescence. Different parameters influence as sample pH and flow rate, eluent flow rate and composition; on BOL sensitivity and elution time was investigated by multifactorial techniques. Adequate dynamic calibration range (r2 =0.9993) was obtained over a concentration interval of 0.029–27.0μgmL−1 BOL. The limits of detection (LOD) and quantification (LOQ) were 0.008 and 0.029μgmL−1, respectively. The average recoveries in explored samples ranged from 95% to 103%. Under optimized conditions, the throughput sample as high as 30h−1 was achieved with high repeatability performance (99%). The proposed development represents a useful and valuable tool emulating the analytical efficiency of the official methodologies for quality control of herbal and phytopharmaceutical drugs containing BOL. Moreover, this approach shows advantages respect to low cost, simplicity and environmental and analyst friendly.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.039
      Issue No: Vol. 184 (2017)
       
  • Separation and preconcentration of riboflavin from human plasma using
           polythionine coated magnetite/hydroxyapatite nanocomposite prior to
           analysis by surfactant-enhanced fluorimetry
    • Authors: Leila Farzin; Mojtaba Shamsipur
      Pages: 109 - 118
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Leila Farzin, Mojtaba Shamsipur
      The exploration of novel adsorption properties of conductive polymers based on hybridization with biocompatible nanomaterials receives an increasing interest. In this regard, hydroxyapatite (HA) bioceramic is of critical importance mainly owing to its facile synthesis, high surface area, economic and low toxicity in biological environments. In this work, we first prepared and characterized a magnetite/hydroxyapatite (Fe3O4/HA) nanocomposite using the bio-waste chicken eggshell via an attractive green way that involved low cost and irrespective of toxicity. Then, polythionine as a novel class of conductive polymers was in situ coated on the synthesized magnetic bioceramic for the separation and preconcentration of riboflavin (vitamin B2) in human plasma before its fluorimetric determination. Considering the putative role of riboflavin in protecting against cancer and cardiovascular diseases, it is essential to evaluate this vitamin in biological fluids. The described method possesses a linear range of 0.75–262.5μgL−1 (R2 =0.9985) and a detection limit of 0.20μgL−1 (signal-to-noise ratio of 3). The relative standard deviations (RSDs) for single-sorbent repeatability and sorbent-to-sorbent reproducibility were less than 4.0% and 7.6% (n=5), respectively. The respective enrichment factor and extraction recovery of the method found to be 35.7 and 98.4%. The analytical performance of method for riboflavin was characterized by good consistency of the results with those obtained by the enzyme-linked immunosorbent assay (ELISA) conventional method (p-value of <0.05). The optimized protocol intended for control determinations of riboflavin in human subjects and is addressed to clinical laboratories.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.087
      Issue No: Vol. 184 (2017)
       
  • Influence of Li+ charge compensator ion on the energy transfer from Pr3+
           to Gd3+ ions in Ca9Mg(PO4)6F2:Gd3+, Pr3+, Li+ phosphor
    • Authors: Sumedha Tamboli; S.J. Dhoble
      Pages: 119 - 127
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Sumedha Tamboli, S.J. Dhoble
      Phototherapy is a renowned treatment for curing skin diseases since ancient times. Phototherapeutic treatment for psoriasis and many other diseases require narrow band ultra violet-B (NB-UVB) light with peak intensity at 313nm to be exposed to the affected part of body. In this paper, we report combustion synthesis of NB-UVB −313nm emitting Ca9Mg(PO4)6F2 phosphors doped with Gd3+, Pr3+ and Li+ ions. The phase formation was confirmed by obtaining X-ray diffraction (XRD) pattern and morphology was studied with the Scanning electron microscopy (SEM) images. Photoluminescence (PL) emission spectra show intense narrow band emission at 313nm under 274nm excitation wavelengths. Emission intensity was enhanced when Ca9Mg(PO4)6F2 compound is co-doped with Pr3+ ions. Excitation spectra of Ca9Mg(PO4)6F2:Gd3+, Pr3+ doped samples shows broad excitation in ultra violet C (UVC) region. Diffuse reflectance spectra (DRS), obtained by UV–visible spectrophotometer, measures the absorption properties of the material. By applying Kubelka Munk function on the diffuse reflectance spectra, band gap of the material is determined. PL decay curves were examined which indicates efficient energy transfer between Pr3+ and Gd3+ ions. Charge compensation effect was also studied by co-doping Li+ ion in host. Emission intensity was found to increase with the addition of charge compensator. The prepared phosphor has potential to convert UVC light into NB-UVB. The luminescence intensity of Gd3+ shows remarkable increase when it is sensitized with Pr3+, and an addition of charge compensator in the form of Li+, show even better results. This phosphor surely has the potential to be used as phototherapy lamp phosphor.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.05.001
      Issue No: Vol. 184 (2017)
       
  • Eigenvalue-eigenvector decomposition (EED) analysis of dissimilarity and
           covariance matrix obtained from total synchronous fluorescence spectral
           (TSFS) data sets of herbal preparations: Optimizing the classification
           approach
    • Authors: Madhumita Tarai; Keshav Kumar; O. Divya; Partha Bairi; Kishor Kumar Mishra; Ashok Kumar Mishra
      Pages: 128 - 133
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Madhumita Tarai, Keshav Kumar, O. Divya, Partha Bairi, Kishor Kumar Mishra, Ashok Kumar Mishra
      The present work compares the dissimilarity and covariance based unsupervised chemometric classification approaches by taking the total synchronous fluorescence spectroscopy data sets acquired for the cumin and non-cumin based herbal preparations. The conventional decomposition method involves eigenvalue-eigenvector analysis of the covariance of the data set and finds the factors that can explain the overall major sources of variation present in the data set. The conventional approach does this irrespective of the fact that the samples belong to intrinsically different groups and hence leads to poor class separation. The present work shows that classification of such samples can be optimized by performing the eigenvalue-eigenvector decomposition on the pair-wise dissimilarity matrix.

      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.088
      Issue No: Vol. 184 (2017)
       
  • Thin film assembly of nanosized cobalt(II)
           bis(5-phenyl-azo-8-hydroxyquinolate) using static step-by-step soft
           surface reaction technique: Structural characterization and optical
           properties
    • Authors: S.M. Seleim; Taymour A. Hamdalla; Mohamed E. Mahmoud
      Pages: 134 - 140
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): S.M. Seleim, Taymour A. Hamdalla, Mohamed E. Mahmoud
      Nanosized (NS) cobalt (II) bis(5-phenyl-azo-8-hydroxyquinolate) (NS Co(II)-(5PA-8HQ)2) thin films have been synthesized using static step-by-step soft surface reaction (SS-b-SSR) technique. Structural and optical characterizations of these thin films have been carried out using thermal gravimetric analysis (TGA), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The HR-TEM results revealed that the assembled Co(II)-complex exhibited a uniformly NS structure particles in the form of nanorods with width and length up to 16.90nm and 506.38nm, respectively. The linear and nonlinear optical properties have been investigated. The identified energy gap of the designed thin film materials was found 4.01eV. The refractive index of deposited Co(II)-complex thin film was identified by thickness-dependence and found as 1.9 at wavelength 1100nm. In addition, the refractive index was varied by about 0.15 due to an increase in the thickness by 19nm.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.068
      Issue No: Vol. 184 (2017)
       
  • Luminescent properties of heterotrinuclear 3d–4f complexes constructed
           from a naphthalenediol-based acyclic bis(salamo)-type ligand
    • Authors: Wen-Kui Dong; Shan-Shan Zheng; Jin-Tong Zhang; Yang Zhang; Yin-Xia Sun
      Pages: 141 - 150
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Wen-Kui Dong, Shan-Shan Zheng, Jin-Tong Zhang, Yang Zhang, Yin-Xia Sun
      Heterotrinuclear 3d–4f complexes with a naphthalenediol-based acyclic bis(salamo)-type ligand have been synthesized and structurally characterized. Spectral titrations clearly show that the heterotrinuclear complexes [Zn2(L)La(OAc)3] (1), [Zn2(L)Ce(OAc)3] (2) and [Zn2(L)Dy(OAc)3(CH3OH)]·CH2Cl2 (3) are acquired by the substitution reaction of the obtained homotrinuclear Zn(II) complex with 1 equiv. of Ln(NO3)3 (Ln3+ =La3+, Ce3+ and Dy3+). Two Zn(II) ions are penta- and hexa-coordinated with geometries of distorted tetragonal pyramid and octahedron. La(III) ion is deca-coordinated, adopting a distorted bicapped square antiprism geometry. Ce(III) ion is nona-coordinated with geometry of distorted capped square antiprism as well as Dy(III) ion. The different coordination modes of acetate ions in complexes 1, 2 and 3 lead to different coordination numbers of the lanthanide(III) ions. Furthermore, the structures and fluorescence properties have been discussed.
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      PubDate: 2017-05-08T15:11:02Z
      DOI: 10.1016/j.saa.2017.04.061
      Issue No: Vol. 184 (2017)
       
  • Preparation and characterization of electrodeposited SnS:In thin films:
           Effect of In dopant
    • Authors: Hosein Kafashan; Zohre Balak
      Pages: 151 - 162
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Hosein Kafashan, Zohre Balak
      SnS:In thin films were grown on fluorine doped tin oxide (FTO) substrate by cathodic electrodeposition technique. The solution was containing 2mM SnCl2 and 16mM Na2S2O3 and different amounts of 1mM InCl3 as In-dopant. The pH, bath temperature, deposition time, and deposition potential (E) were fixed at 2.1, 60°C, 30min, and −1V, respectively. The XRD results showed that the synthesized films were polycrystalline orthorhombic SnS. The XPS results demonstrated that the films were composed of Sn, S and In. According to the FESEM images, an increase in In-dopant concentration leads to a change in morphology from grain-like to sheet-like having a nanoscale thickness of 20–80nm and fiber-like. The PL spectra of undoped SnS exhibited four emission peaks including a UV peak, two blue emission peaks, and an IR emission peak. According to the UV–Vis spectra, the direct band gap of SnS:In thin films was estimated to be 1.40–1.66eV.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.04.082
      Issue No: Vol. 184 (2017)
       
  • Study on molecular structure, spectroscopic properties (FTIR and
           UV–Vis), NBO, QTAIM, HOMO-LUMO energies and docking studies of
           5-fluorouracil, a substance used to treat cancer
    • Authors: Michell O. Almeida; Daiane A.S. Barros; Sheila C. Araujo; Sergio H.D.M. Faria; Vinicius G. Maltarollo; Kathia M. Honorio
      Pages: 169 - 176
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Michell O. Almeida, Daiane A.S. Barros, Sheila C. Araujo, Sergio H.D.M. Faria, Vinicius G. Maltarollo, Kathia M. Honorio
      Cancer cells can expand to other parts of body through blood system and nodes from a mechanism known as metastasis. Due to the large annual growth of cancer cases, various biological targets have been studied and related to this disorder. A very interesting target related to cancer is human epidermal growth factor receptor 2 (HER2). In this study, we analyzed the main intermolecular interactions between a drug used in the cancer treatment (5-fluorouracil) and HER2. Molecular modeling methods were also employed to assess the molecular structure, spectroscopic properties (FTIR and UV–Vis), NBO, QTAIM and HOMO-LUMO energies of 5-FU. From the docking simulations it was possible to analyze the interactions that occur between some residues in the binding site of HER2 and 5-FU. To validate the choice of basis set that was used in the NBO and QTAIM analyses, theoretical calculations were performed to obtain FT-IR and UV/Vis spectra, and the theoretical results are consistent with the experimental data, showing that the basis set chosen is suitable. For the maximum λ from the theoretical calculation (254.89nm) of UV/Vis, the electronic transition from HOMO to LUMO occurs at 4.89eV. From NBO analyses, we observed interactions between Asp863 and 5-FU, i.e. the orbitals with high transfer of electrons are LP O15 (donor NBO) and BD* (π) N1-H10 (acceptor NBO), being that the value of this interaction is 7.72kcal/mol. Results from QTAIM indicate one main intermolecular H bond, which is necessary to stabilize the complex formed between the ligands and the biological target. Therefore, this study allowed a careful evaluation on the main structural, spectroscopic and electronic properties involved in the interaction between 5-FU and HER2, an important biological complex related to the cancer treatment.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.04.070
      Issue No: Vol. 184 (2017)
       
  • A highly sensitive turn-on fluorescent chemosensor for recognition of Zn2+
           and Hg2+ and applications
    • Authors: Xu Tang; Juan Han; Yun Wang; Xu Bao; Liang Ni; Lei Wang; Longhua Li
      Pages: 177 - 183
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Xu Tang, Juan Han, Yun Wang, Xu Bao, Liang Ni, Lei Wang, Longhua Li
      A fluorescence probe has been designed and synthesized, and applied with a combined theoretical and experimental study. Research suggests that the probe can be used to sense Zn2+ and Hg2+ through selective turn-on fluorescence responses in the aqueous HEPES buffer (0.05M, pH=7.4). The limit of detection (LOD) were determined as 1.46×10−7 M (Zn2+) and 2.50×10−7 M (Hg2+). Moreover, based on DFT, the geometry optimizations of probe 1, [1-Hg2+] complex and [1-Zn2+] complex were carried out using the Gaussian 09 program, in which the B3LYP function was used. The electronic properties of free probe 1 and the metal complexes were studied based on the Natural Bond Orbital (NBO) analyses. The probe 1 has also been successfully applied to detection of Zn2+ and Hg2+ in living cells.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.011
      Issue No: Vol. 184 (2017)
       
  • Spectroscopic analysis of hot-water- and dilute-acid-extracted hardwood
           and softwood chips
    • Authors: Joni Lehto; Jarmo Louhelainen; Marko Huttunen; Raimo Alén
      Pages: 184 - 190
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Joni Lehto, Jarmo Louhelainen, Marko Huttunen, Raimo Alén
      Hot-water and dilute sulfuric acid pretreatments were performed prior to chemical pulping for silver/white birch (Betula pendula/B. pubescens) and Scots pine (Pinus sylvestris) chips to determine if varying pretreatment conditions on the original wood material were detectable via attenuated total reflectance (ATR) infrared spectroscopy. Pretreatment conditions varied with respect to temperature (130°C and 150°C) and treatment time (from 30min to 120min). The effects of the pretreatments on the composition of wood chips were determined by ATR infrared spectroscopy. The spectral data were compared to those determined by common wood chemistry analyses to evaluate the suitability of ATR spectroscopy method for rapid detection of changes in the wood chemical composition caused by different pretreatment conditions. In addition to determining wood species-dependent differences in the wood chemical composition, analytical results indicated that most essential lignin- and carbohydrates-related phenomena taking place during hot-water and acidic pretreatments could be described by applying this simple spectral method requiring only a small sample amount and sample preparation. Such information included, for example, the cleavage of essential lignin bonds (i.e., mainly β-O-4 linkages in guaiacyl and syringyl lignin) and formation of newly condensed lignin structures under different pretreatment conditions. Carbohydrate analyses indicated significant removal of hemicelluloses (especially hardwood xylan) and hemicelluloses-derived acetyl groups during the pretreatments, but they also confirmed the highly resistant nature of cellulose towards mild pretreatments.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.010
      Issue No: Vol. 184 (2017)
       
  • Combination photodynamic therapy of human breast cancer using salicylic
           acid and methylene blue
    • Authors: Reza Hosseinzadeh; Khatereh Khorsandi; Maryam Jahanshiri
      Pages: 198 - 203
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Reza Hosseinzadeh, Khatereh Khorsandi, Maryam Jahanshiri
      The objective of this study was to evaluate the effects of combination therapy with methylene blue (MB) assisted photodynamic therapy (PDT) and salicylic acid (SA) as chemo-therapy anticancer agent. The binding of salicylic acid to methylene blue was studied using spectrophotometric method. The results show the 1:2 complex formation between SA and MB. The binding constants and related Gibbs free energies o are obtained (Kb1 =183.74, Kb2 =38.13 and ∆ G b1 ° =12.92kJ·mol−1, ∆ G b2 ° =9.02kJ·mol−1). The spectrophotometric results show the improvement in solubilization and reduction prevention for SA and MB in the complex form. These results are in agreements with cellular experiments. The dark toxicity measurements represent the improve efficacy of chemotherapy using combination of SA and MB. The photodynamic therapy results (using red LED as light source (630nm; power density: 30mWcm−2)) show that the cancer cell killing efficiency of MB increases in the combination with SA due to reduction prevention and stabilization of monomeric form of MB.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.008
      Issue No: Vol. 184 (2017)
       
  • Interaction between triethanolamine and singlet or triplet excited state
           of xanthene dyes in aqueous solution
    • Authors: Shuang Li; Huiyu Zhang; Rong Lu; Anchi Yu
      Pages: 204 - 210
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Shuang Li, Huiyu Zhang, Rong Lu, Anchi Yu
      Triethanolamine (TEOA) has been often used as a hole-scavenger in dye-sensitized semiconductor photocatalytic systems. However, the femtosecond time-resolved kinetics of the interaction between a sensitized dye and TEOA has not been reported in literatures. Herein, we selected four commonly used xanthene dyes, such as fluorescein, dibromofluorescein, eosin Y, and erythrosine B, and studied their ultrafast fluorescence quenching dynamics in the presence of TEOA in aqueous solution, respectively, by using both femtosecond transient absorption and time-resolved fluorescence measurements. We obtained the electron transfer rate from TEOA to each photoexcited xanthene dye in 2.0 M TEOA solution. We also obtained the intersystem crossing rate of each xanthene dye in aqueous solution with fluorescence quantum yield and lifetime measurements. Finally we found that TEOA mainly interacts with the singlet excited-state of fluorescein, dibromofluorescein, and eosin Y, and that TEOA can interact with both the singlet and triplet excited-states of erythrosine B in high concentration of TEOA aqueous solution.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.009
      Issue No: Vol. 184 (2017)
       
  • Infrared reflectometry of skin: Analysis of backscattered light from
           different skin layers
    • Authors: Miguel A. Pleitez; Otto Hertzberg; Alexander Bauer; Tobias Lieblein; Mathias Glasmacher; Hans Tholl; Werner Mäntele
      Pages: 220 - 227
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Miguel A. Pleitez, Otto Hertzberg, Alexander Bauer, Tobias Lieblein, Mathias Glasmacher, Hans Tholl, Werner Mäntele
      We have recently reported infrared spectroscopy of human skin in vivo using quantum cascade laser excitation and photoacoustic or photothermal detection for non-invasive glucose measurement . Here, we analyze the IR light diffusely reflected from skin layers for spectral contributions of glucose. Excitation of human skin by an external cavity tunable quantum cascade laser in the spectral region from 1000 to 1245cm−1, where glucose exhibits a fingerprint absorption, yields reflectance spectra with some contributions from glucose molecules. A simple three-layer model of skin was used to calculate the scattering intensities from the surface and from shallow and deeper layers using the Boltzmann radiation transfer equation. Backscattering of light at wavelengths around 10μm from the living skin occurs mostly from the Stratum corneum top layers and the shallow layers of the living epidermis. The analysis of the polarization of the backscattered light confirms this calculation. Polarization is essentially unchanged; only a very small fraction (<3%) is depolarized at 90° with respect to the laser polarization set at 0°. Based on these findings, we propose that the predominant part of the backscattered light is due to specular reflectance and to scattering from layers close to the surface. Diffusely reflected light from deeper layers undergoing one or more scattering processes would appear with significantly altered polarization. We thus conclude that a non-invasive glucose measurement based on backscattering of IR light from skin would have the drawback that only shallow layers containing some glucose at concentrations only weakly related to blood glucose are monitored.
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      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.04.080
      Issue No: Vol. 184 (2017)
       
  • Influence of polyethylene glycol on the phase transition of poly(butylene
           adipate) thin films: Polymorphic control
    • Authors: Yujing Chen; Isao Noda; Young Mee Jung
      Pages: 228 - 234
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Yujing Chen, Isao Noda, Young Mee Jung
      Control of the polymorphic crystals formation of poly(butylene adipate) (PBA) is crucial to tailor its performance. In the present study, we investigated the effect of polyethylene glycol (PEG) with molecular weight of 400 on the polymorphic crystal of PBA thin films using x-ray diffraction (XRD), temperature-dependent infrared-reflection absorbance spectroscopy (IRRAS) and two-dimensional correlation analysis (2DCOS). XRD and IRRAS results suggest that the PBA thin film tends to grow α-form crystal with addition of PEG at room temperature. Increasing the PEG contribution to 30wt%, the PBA thin film shows α-form crystal only. Temperature-dependent IRRAS spectra indicate that pure PBA thin film exhibited α/β mixed crystal and the β-to-α transition was observed during the heating process. After the incorporation of PEG, PEG not only inhibits the growth of β crystal but also suppresses the β-to-α transition during the heating process. In addition, we unexpectedly captured three different amorphous bands of CO stretching of pure PBA from the asynchronous 2D correlation spectrum. The band at 1740cm−1 corresponded to the amorphous phase of PBA at room temperature, whereas 1746 and 1760cm−1 respectively arose from the amorphous phase of PBA melting from α-form crystal and β-form crystal. This study demonstrated that the crystal form of PBA can be modified by blending with PEG, providing a new method to control the crystal modification and physical properties of polymorphic PBA in their blend system.
      Graphical abstract image

      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.003
      Issue No: Vol. 184 (2017)
       
  • Strategy for improved NH2 detection in combustion environments using an
           Alexandrite laser
    • Authors: Christian Brackmann; Bo Zhou; Per Samuelsson; Vladimir A. Alekseev; Alexander A. Konnov; Zhongshan Li; Marcus Aldén
      Pages: 235 - 242
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Christian Brackmann, Bo Zhou, Per Samuelsson, Vladimir A. Alekseev, Alexander A. Konnov, Zhongshan Li, Marcus Aldén
      A new scheme for NH2 detection by means of laser-induced fluorescence (LIF) with excitation around wavelength 385nm, accessible using the second harmonic of a solid-state Alexandrite laser, is presented. Detection of NH2 was confirmed by identification of corresponding lines in fluorescence excitation spectra measured in premixed NH3-air flames and on NH2 radicals generated through NH3 photolysis in a nonreactive flow at ambient conditions. Moreover, spectral simulations allow for tentative NH2 line identification. Dispersed fluorescence emission spectra measured in flames and photolysis experiments showed lines attributed to vibrational bands of the NH2 A2A1 ←X2B1 transition but also a continuous structure, which in flame was observed to be dependent on nitrogen added to the fuel, apparently also generated by NH2. A general conclusion was that fluorescence interferences need to be carefully considered for NH2 diagnostics in this spectral region. Excitation for laser irradiances up to 0.2GW/cm2 did not result in NH2 fluorescence saturation and allowed for efficient utilization of the available laser power without indication of laser-induced photochemistry. Compared with a previously employed excitation/detection scheme for NH2 at around 630nm, excitation at 385.7nm showed a factor of ~15 higher NH2 signal. The improved signal allowed for single-shot NH2 LIF imaging on centimeter scale in flame with signal-to-noise ratio of 3 for concentrations around 1000ppm, suggesting a detection limit around 700ppm. Thus, the presented approach for NH2 detection provides enhanced possibilities for characterization of fuel-nitrogen combustion chemistry.
      Graphical abstract image

      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.002
      Issue No: Vol. 184 (2017)
       
  • Thickness and optical constants calculation for chalcogenide-alkali metal
           Se80Te8(NaCl)12 thin film
    • Authors: M.I. Abd-Elrahman; A.A. Abu-Sehly; Y.M. Bakier; M.M. Hafiz
      Pages: 243 - 248
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): M.I. Abd-Elrahman, A.A. Abu-Sehly, Y.M. Bakier, M.M. Hafiz
      Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.
      Graphical abstract image

      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.013
      Issue No: Vol. 184 (2017)
       
  • A new azine derivative colorimetric and fluorescent dual-channel probe for
           cyanide detection
    • Authors: Bin Yu; Chun-Yu Li; Yin-Xia Sun; Hao-Ran Jia; Jian-Qiang Guo; Jing Li
      Pages: 249 - 254
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Bin Yu, Chun-Yu Li, Yin-Xia Sun, Hao-Ran Jia, Jian-Qiang Guo, Jing Li
      A novel azine derivative colorimetric and fluorescent dual-channel probe salicylaldehyde hydrazine-3,5-dibromosalicylaldehyde (1) has been designed, synthesized and characterized. The probe 1 is confirmed to have especial selectivity and good sensitivity on detecting CN− via UV–vis absorption and fluorescence spectrum in aqueous solution (H2O/DMSO, 1:4, v/v). This colorimetric and fluorescent dual-channel probe response to CN− owed to the deprotonation process and established the mechanism by using 1H NMR spectroscopy. Further researches showed that the detection limit of the probe 1 to CN− anions is 8.01×10−9 M, significantly lower than the maximum level 1.9×10−6 M in potable water from WHO guidelines.
      Graphical abstract image

      PubDate: 2017-05-13T06:45:36Z
      DOI: 10.1016/j.saa.2017.05.012
      Issue No: Vol. 184 (2017)
       
  • Multiway analysis methods applied to the fluorescence excitation-emission
           dataset for the simultaneous quantification of valsartan and amlodipine in
           tablets
    • Authors: Erdal Dinç; Zehra Ceren Ertekin; Eda Büker
      Pages: 255 - 261
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Erdal Dinç, Zehra Ceren Ertekin, Eda Büker
      In this study, excitation-emission matrix datasets, which have strong overlapping bands, were processed by using four different chemometric calibration algorithms consisting of parallel factor analysis, Tucker3, three-way partial least squares and unfolded partial least squares for the simultaneous quantitative estimation of valsartan and amlodipine besylate in tablets. In analyses, preliminary separation step was not used before the application of parallel factor analysis Tucker3, three-way partial least squares and unfolded partial least squares approaches for the analysis of the related drug substances in samples. Three-way excitation-emission matrix data array was obtained by concatenating excitation-emission matrices of the calibration set, validation set, and commercial tablet samples. The excitation-emission matrix data array was used to get parallel factor analysis, Tucker3, three-way partial least squares and unfolded partial least squares calibrations and to predict the amounts of valsartan and amlodipine besylate in samples. For all the methods, calibration and prediction of valsartan and amlodipine besylate were performed in the working concentration ranges of 0.25–4.50μg/mL. The validity and the performance of all the proposed methods were checked by using the validation parameters. From the analysis results, it was concluded that the described two-way and three-way algorithmic methods were very useful for the simultaneous quantitative resolution and routine analysis of the related drug substances in marketed samples.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.04.081
      Issue No: Vol. 184 (2017)
       
  • Investigation of the binding affinity in vitamin B12—Bovine serum
           albumin system using various spectroscopic methods
    • Authors: Magdalena Makarska-Bialokoz
      Pages: 262 - 269
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Magdalena Makarska-Bialokoz
      The binding affinity between vitamin B12 (VitB12) and bovine serum albumin (BSA) has been investigated in aqueous solution at pH=7.4, employing UV–vis absorption and steady-state, synchronous and three-dimensional fluorescence spectra techniques. Representative effects noted for BSA intrinsic fluorescence resulting from the interactions with VitB12 confirm the formation of π-π stacked non-covalent and non-fluorescent complexes in the system VitB12-BSA. All the determined parameters, the binding, fluorescence quenching and bimolecular quenching rate constants (of the order of 104 Lmol−1, 103 Lmol−1 and 1011 Lmol−1 s−1, respectively), as well as Förster resonance energy transfer parameters validate the mechanism of static quenching. The interaction with VitB12 induces folding of the polypeptide chains around Trp residues of BSA, resulting in a more hydrophobic surrounding. Presented outcomes suggest that the addition of VitB12 can lead to the more organized BSA conformation and its more folded tertiary structure, what could influence the physiological functions of bovine serum albumin, notably in case of its overuse or abnormal metabolism.
      Graphical abstract image

      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.05.014
      Issue No: Vol. 184 (2017)
       
  • An experimental and theoretical study of solvent hydrogen-bond-donating
           capacity effects on ultrafast intramolecular charge transfer of LD 490
    • Authors: Hui Li; Hang Yin; Xiaochun Liu; Ying Shi; Mingxing Jin; Dajun Ding
      Pages: 270 - 276
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Hui Li, Hang Yin, Xiaochun Liu, Ying Shi, Mingxing Jin, Dajun Ding
      The excited-state intramolecular charge transfer (ICT) of LD 490 were investigated in different hydrogen-bond-donating solvents (α scale) on the basis of the Kamlet–Taft solvatochromic parameters (π*, α, β). The femtosecond transient absorption spectra and the kinetics decay rate reveal that with an increase of solvent's α capacity, the long-lived picosecond process, which is attributed to the ICT, becomes much faster. Combining with time-dependent density functional theory (TDDFT) calculations, we demonstrate that the enhancement of α acidity substantially increases the electronegativity of the carbonyl oxygen in LD 490, which strengthen excited-state intermolecular hydrogen bonding interactions and consequently facilitate the ICT process.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.027
      Issue No: Vol. 184 (2017)
       
  • Application of NIRS coupled with PLS regression as a rapid,
           non-destructive alternative method for quantification of KBA in Boswellia
           sacra
    • Authors: Ahmed Al-Harrasi; Najeeb Ur Rehman; Fazal Mabood; Muhammaed Albroumi; Liaqat Ali; Javid Hussain; Hidayat Hussain; René Csuk; Abdul Latif Khan; Tanveer Alam; Saif Alameri
      Pages: 277 - 285
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Ahmed Al-Harrasi, Najeeb Ur Rehman, Fazal Mabood, Muhammaed Albroumi, Liaqat Ali, Javid Hussain, Hidayat Hussain, René Csuk, Abdul Latif Khan, Tanveer Alam, Saif Alameri
      In the present study, for the first time, NIR spectroscopy coupled with PLS regression as a rapid and alternative method was developed to quantify the amount of Keto-β-Boswellic Acid (KBA) in different plant parts of Boswellia sacra and the resin exudates of the trunk. NIR spectroscopy was used for the measurement of KBA standards and B. sacra samples in absorption mode in the wavelength range from 700–2500nm. PLS regression model was built from the obtained spectral data using 70% of KBA standards (training set) in the range from 0.1ppm to 100ppm. The PLS regression model obtained was having R-square value of 98% with 0.99 corelationship value and having good prediction with RMSEP value 3.2 and correlation of 0.99. It was then used to quantify the amount of KBA in the samples of B. sacra. The results indicated that the MeOH extract of resin has the highest concentration of KBA (0.6%) followed by essential oil (0.1%). However, no KBA was found in the aqueous extract. The MeOH extract of the resin was subjected to column chromatography to get various sub-fractions at different polarity of organic solvents. The sub-fraction at 4% MeOH/CHCl3 (4.1% of KBA) was found to contain the highest percentage of KBA followed by another sub-fraction at 2% MeOH/CHCl3 (2.2% of KBA). The present results also indicated that KBA is only present in the gum-resin of the trunk and not in all parts of the plant. These results were further confirmed through HPLC analysis and therefore it is concluded that NIRS coupled with PLS regression is a rapid and alternate method for quantification of KBA in Boswellia sacra. It is non-destructive, rapid, sensitive and uses simple methods of sample preparation.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.018
      Issue No: Vol. 184 (2017)
       
  • Optical nonlinearity and charge transfer analysis of pyrene adsorbed on
           silver: Computational and experimental investigations
    • Authors: U. Reeta Felscia; Beulah J.M. Rajkumar; Pranitha Sankar; Reji Philip; M. Briget Mary
      Pages: 286 - 293
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): U. Reeta Felscia, Beulah J.M. Rajkumar, Pranitha Sankar, Reji Philip, M. Briget Mary
      The interaction of pyrene on silver has been investigated using both experimental and computational methods. Hyperpolarizabilities computed theoretically together with experimental nonlinear absorption from open aperture Z-scan measurements, point towards a possible use of pyrene adsorbed on silver in the rational design of NLO devices. Presence of a red shift in both simulated and experimental UV–Vis spectra confirms the adsorption on silver, which is due to the electrostatic interaction between silver and pyrene, inducing variations in the structural parameters of pyrene. Fukui calculations along with MEP plot predict the electrophilic nature of the silver cluster in the presence of pyrene, with NBO analysis revealing that the adsorption causes charge redistribution from the first three rings of pyrene towards the fourth ring, from where the 2p orbitals of carbon interact with the valence 5s orbitals of the cluster. This is further confirmed by the downshifting of ring breathing modes in both the experimental and theoretical Raman spectra.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.021
      Issue No: Vol. 184 (2017)
       
  • Hydrogen bonding and π-π stacking in nicotinamide/H2O mixtures
    • Authors: Cuiping Zhai; Ping Zhang; Peng Peng; Bingbing Hou; Lina Li
      Pages: 294 - 298
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Cuiping Zhai, Ping Zhang, Peng Peng, Bingbing Hou, Lina Li
      The interactions between nicotinamide (NA) and H2O were studied using UV–visible spectra (UV–Vis), cyclic voltammetry (CV), nuclear magnetic resonance (NMR), density functional theory (DFT) and atoms in molecules (AIM) analysis. According to the changes of the UV–Vis spectra and the oxidation and reduction potentials in cyclic voltammograms of NA in aqueous solution, it was found that hydrogen bonding occurred between NA and H2O molecules. Quantum chemistry calculations and AIM analysis further confirmed the existence of hydrogen bonding between H2O molecules and the amide group, the nitrogen atom, and hydrogen atoms on the pyridine ring of NA molecules. In addition, the NMR results demonstrated that the π-π stacking between NA pyridine rings could be formed at higher concentrations.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.020
      Issue No: Vol. 184 (2017)
       
  • A selective naked-eye chemosensor derived from 2-methoxybenzylamine and
           2,3-dihydroxybenzaldehyde - synthesis, spectral characterization and
           electrochemistry of its bis-bidentates Schiff bases metal complexes
    • Authors: Aggoun Djouhra; Ourari Ali; Ruiz-Rosas Ramiro; Morallon Emilia
      Pages: 299 - 307
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Aggoun Djouhra, Ourari Ali, Ruiz-Rosas Ramiro, Morallon Emilia
      A new colorimetric receptor HL, acting as a bidentate Schiff base ligand, has been synthesized by condensation of 2-methoxybenzylamine on 2,3-dihydroxybenzaldehyde in a methanolic solution. Interestingly, this chelating agent can selectively detect Cu 2 +, Co 2 +, Fe 2 + and Fe 3 + ions with a simple and an easy-to-make, well defined naked-eye visible color changes in two different solvents like acetonitrile and methanol. This bidentate ligand coordinates three metal ions of Co(II), Cu(II) and Fe(II) via nitrogen and oxygen atoms. The molecular structures of the synthesized compounds were elucidated by various physicochemical properties such as the elemental analysis, FT-IR, HNMR, UV–Vis and the Mass spectrometry. The resulting general formulae [M(L)2·H2O] (M(II)=Cu, Fe, Co) are proposed as mononuclear complexes. The solvatochromism properties of these compounds were studied with their absorption spectra using different solvents as methanol (MeOH), acetonitrile (AN), tetrahydrofuran (THF), dimethylformamid (DMF), dimethylsulfoxid (DMSO) and dichloromethane (DC). The Electrochemical behavior of copper complex was explored in DMF solutions by cyclic voltammetry (CV) with two working electrodes: glassy carbon (GC) and platinum electrode (Pt). This study reveals that copper complex shows successively two redox systems as Cu III/II and Cu II/I . The Fe III/II and Co II/I redox systems have also been studied in DMF and DMSO media.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.022
      Issue No: Vol. 184 (2017)
       
  • Theoretical spectroscopic insights of tautomers and enantiomers of
           penicillamine
    • Authors: J. Mendes; K.J. de Almeida; J.L. Neto; T.C. Ramalho; H.A. Duarte
      Pages: 308 - 317
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): J. Mendes, K.J. de Almeida, J.L. Neto, T.C. Ramalho, H.A. Duarte
      B3LYP and MP2 calculations have been carried out to investigate tautomers and enantiomers of penicillamine (Pen). Their infrared (IR), ultraviolet (UV), circular dichroism (CD) and nuclear magnetic resonance (NMR) spectra were obtained at linear-response, time-dependent DFT (TD-DFT). IR, UV and NMR spectra cannot be used to identify Pen enantiomers, showing nearly equal spectral profiles. CD spectra, however, give rise to completely symmetric signals, forming a perfect specular image to each other. Distinct CD profiles were also obtained for Pen tautomers. Important IR differences were found in positions and intensities of the vibrational stretching bands involving acid and amine groups of Pen tautomers. The highest electron transitions involving HOMO-LUMO orbitals show to be of major importance in the computed UV spectra, showing a large red-shift around 30nm as the zwitterionic and neutral Pen spectra are compared. NMR results show to be quite useful for identification of Pen tautomers since clear differences are found by means of the computed shielding tensors as well as spin-spin coupling constants 1J(N,H) data.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.025
      Issue No: Vol. 184 (2017)
       
  • Hydrogen bonded charge transfer molecular salt (4-chloro
           anilinium-3-nitrophthalate) for photophysical and pharmacological
           applications
    • Authors: K. Singaravelan; A. Chandramohan; M. Saravanabhavan; I.V. Muthu Vijayan Enoch; V.S. Suganthi
      Pages: 318 - 326
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): K. Singaravelan, A. Chandramohan, M. Saravanabhavan, I.V. Muthu Vijayan Enoch, V.S. Suganthi
      Radical scavenging activity against DPPH radical and binding properties of a hydrogen bonded charge transfer molecular salt 4-chloro anilinium-3-nitrophthalate(CANP) with calf thymus DNA has been studied by electronic absorption and emission spectroscopy. The molecular structure and crystallinity of the CANP salt have been established by carried out powder and single crystal X-ray diffraction analysis which indicated that cation and anion are linked through strong N+ H…O– type of hydrogen bond. FTIR spectroscopic study was carried out to know the various functional groups present in the crystal. 1H and 13C NMR spectra were recorded to further confirm the molecular structure of the salt crystal. The thermal stability of the title salt was established by TG/DTA analyses simultaneously on the powdered sample of the title crystal. Further, the CANP salt was examined against various bacteria and fungi strains which showed a remarkable antimicrobial activity compared to that of the standards Ciproflaxin and Clotrimazole. The results showed that the CANP salt could interact with CT-DNA through intercalation. Antioxidant studies of the substrates alone and synthesized CANP salt showed that the latter has been better radical scavenging activity than that of the former against DPPH radical. The third order nonlinear susceptibility of the CANP salt was established by the Z-scan study.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.016
      Issue No: Vol. 184 (2017)
       
  • Pressure induced transformations in sorbic acid
    • Authors: G.D. Saraiva; J.R. Maia; J.A. Lima; C.E.S. Nogueira; P.T.C. Freire; F.F. de Sousa; A.M.R. Teixeira; J. Mendes Filho
      Pages: 327 - 334
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): G.D. Saraiva, J.R. Maia, J.A. Lima, C.E.S. Nogueira, P.T.C. Freire, F.F. de Sousa, A.M.R. Teixeira, J. Mendes Filho
      This research reports a pressure dependent Raman study of the sorbic acid between 0.0 and 10.0GPa. The unpolarized Raman spectra were measured in the spectral range of 20–3000cm−1. The high-pressure Raman scattering study of the sorbic acid showed that it underwent a gradual, disordering process. At the room temperature and at the ambient pressure conditions, the crystal structure of the sorbic acid belongs to the monoclinic system with a C2/c (C2h 6) space group. The pressure increase induced a higher disorder in the monoclinic unit cell, since a single bending mode, and only very broad stretching Raman modes are present at pressure of ~10GPa. Upon pressure release the high-pressure phase transforms directly into the ambient-pressure phase. The presence of the internal vibrational modes is a guarantee that the molecular structure is maintained. Beyond this, the presence of external modes shows that the crystal has a memory to reverse the process and suggest that the crystal, which was in high disorder (broad Raman bands), does not suffer decomposition in the crystalline structure. The DFT calculations for the sorbic acid were performed in order to understand the vibrational properties. The theoretical study showed that the volume of the unit cell and beta angle decrease significatively when passing from the 0.0GPa to 8.0GPa. The decreases in the volume and beta angle of this particular unit cell were supposed to induce the larger increase in the bandwidths of the observed bands, pointing to some disorder in the monoclinic phase.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.019
      Issue No: Vol. 184 (2017)
       
  • Quantitative determination of Auramine O by terahertz spectroscopy with
           2DCOS-PLSR model
    • Authors: Huo Zhang; Zhi Li; Tao Chen; Binyi Qin
      Pages: 335 - 341
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Huo Zhang, Zhi Li, Tao Chen, Binyi Qin
      Residues of harmful dyes such as Auramine O (AO) in herb and food products threaten the health of people. So, fast and sensitive detection techniques of the residues are needed. As a powerful tool for substance detection, terahertz (THz) spectroscopy was used for the quantitative determination of AO by combining with an improved partial least-squares regression (PLSR) model in this paper. Absorbance of herbal samples with different concentrations was obtained by THz-TDS in the band between 0.2THz and 1.6THz. We applied two-dimensional correlation spectroscopy (2DCOS) to improve the PLSR model. This method highlighted the spectral differences of different concentrations, provided a clear criterion of the input interval selection, and improved the accuracy of detection result. The experimental result indicated that the combination of the THz spectroscopy and 2DCOS-PLSR is an excellent quantitative analysis method.
      Graphical abstract image

      PubDate: 2017-05-18T07:28:19Z
      DOI: 10.1016/j.saa.2017.05.017
      Issue No: Vol. 184 (2017)
       
  • A highly selective long-wavelength fluorescent probe for hydrazine and its
           application in living cell imaging
    • Authors: Yuanqiang Hao; Yintang Zhang; Kehong Ruan; Fanteng Meng; Ting Li; Jinsheng Guan; Lulu Du; Peng Qu; Maotian Xu
      Pages: 355 - 360
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Yuanqiang Hao, Yintang Zhang, Kehong Ruan, Fanteng Meng, Ting Li, Jinsheng Guan, Lulu Du, Peng Qu, Maotian Xu
      A highly selective long-wavelength turn-on fluorescent probe has been developed for the detection of N2H4. The probe was prepared by conjugation the tricyanofuran-based D-π-A system with a recognizing moiety of acetyl group. In the presence of N2H4, the probe can be effectively hydrazinolysized and produce a turn-on fluorescent emission at 610nm as well as a large red-shift in the absorption spectrum corresponding to a color change from yellow to blue. The sensing mechanism was confirmed by HPLC, MS, UV-vis, emission spectroscopic and theoretical calculation studies. The probe displayed high selectivity and sensitivity for N2H4 with a LOD (limit of detection) of 0.16μM. Moreover, the probe was successfully utilized for the detection of hydrazine in living cells.
      Graphical abstract image

      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.04.041
      Issue No: Vol. 184 (2017)
       
  • FTIR analysis on aging characteristics of ABS/PC blend under
           UV-irradiation in air
    • Authors: Jiarong Li; Fu Chen; Long Yang; Long Jiang; Yi Dan
      Pages: 361 - 367
      Abstract: Publication date: 5 September 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 184
      Author(s): Jiarong Li, Fu Chen, Long Yang, Long Jiang, Yi Dan
      Fourier Transform Infrared Spectroscopy (FTIR) is adopted to study the aging characteristics of poly(acrylonitrile–butadiene–styrene)/polycarbonate (ABS/PC) blend under UV-irradiation in air by analyzing the variation of the three main absorbance at about 967cm−1, 1720cm−1 and 3420cm−1 associated with carbon-hydrogen bonds belonging to 1,4 butadiene, carbonyl and hydroxyl groups, respectively. Results indicate that, under UV-irradiation in air, the photo-oxidation of the blend is not a simple combination of the photo-oxidation of corresponding ABS and PC themselves and takes place predominantly at the ABS component. Due to the interaction between the two components and the Fries rearrangement taken place in the PC component during the UV-irradiation in air, the ABS/PC blends behave higher photo-stability than ABS has.
      Graphical abstract image

      PubDate: 2017-05-23T07:25:14Z
      DOI: 10.1016/j.saa.2017.04.075
      Issue No: Vol. 184 (2017)
       
 
 
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