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Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.717]   [H-I: 80]   [16 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [3118 journals]
  • Preparation of cellophane-based substrate and its SERS performance on the
           detection of CV and acetamiprid
    • Authors: Wenxian Wei; Qingli Huang
      Pages: 8 - 13
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Wenxian Wei, Qingli Huang
      Cellophane was taken as platform to fabricate a new SERS substrate via silver mirror action. From Raman spectra, it can be found that the Raman signal of Ag-coated cellophane has little influence on the detection of analytes molecules. Raman mapping analysis showed that the cellophane-based SERS substrate has good uniformity. By using the Ag-coated cellophane, 10−6–10−9 M crystal violet (CV) could be detected by this substrate and the reproducibility of the substrate was also involved. Acetamiprid was also detected via Ag-coated cellophane. The result showed that cellophane is suitable to be taken as platform for preparation of SERS substrates.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.062
      Issue No: Vol. 193 (2017)
       
  • Multi-spectroscopic and molecular docking studies on the interaction of
           darunavir, a HIV protease inhibitor with calf thymus DNA
    • Authors: Jie-Hua Shi; Kai-Li Zhou; Yan-Yue Lou; Dong-Qi Pan
      Pages: 14 - 22
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Jie-Hua Shi, Kai-Li Zhou, Yan-Yue Lou, Dong-Qi Pan
      Molecular interaction of darunavir (DRV), a HIV protease inhibitor with calf thymus deoxyribonucleic acid (ct-DNA) was studied in physiological buffer (pH7.4) by multi-spectroscopic approaches hand in hand with viscosity measurements and molecular docking technique. The UV absorption and fluorescence results together revealed the formation of a DRV–ct-DNA complex having binding affinities of the order of 103 M−1, which was more in keeping with the groove binding. The results that DRV bound to ct-DNA via groove binding mode was further evidenced by KI quenching studies, viscosity measurements, competitive binding investigations with EB and Rhodamine B and CD spectral analysis. The effect of ionic strength indicated the negligible involvement of electrostatic interaction between DRV and ct-DNA. The thermodynamic parameters regarding the binding interaction of DRV with ct-DNA in terms of enthalpy change (ΔH 0) and entropy change (ΔS 0) were −63.19kJ mol−1 and −141.92J mol−1 K−1, indicating that hydrogen bonds and van der Waals forces played a predominant role in the binding process. Furthermore, molecular simulation studies suggested that DRV molecule was prone to bind in the A-T rich region of the minor groove of DNA.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.061
      Issue No: Vol. 193 (2017)
       
  • IR spectra and properties of solid acetone, an interstellar and cometary
           molecule
    • Authors: Reggie L. Hudson; Perry A. Gerakines; Robert F. Ferrante
      Pages: 33 - 39
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Reggie L. Hudson, Perry A. Gerakines, Robert F. Ferrante
      Mid-infrared spectra of amorphous and crystalline acetone are presented along with measurements of the refractive index and density for both forms of the compound. Infrared band strengths are reported for the first time for amorphous and crystalline acetone, along with IR optical constants. Vapor pressures and a sublimation enthalpy for crystalline acetone also are reported. Positions of 13C-labeled acetone are measured. Band strengths are compared to gas-phase values and to the results of a density-functional calculation. A 73% error in previous work is identified and corrected.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.055
      Issue No: Vol. 193 (2017)
       
  • Wavelength selection for portable noninvasive blood component measurement
           system based on spectral difference coefficient and dynamic spectrum
    • Authors: Ximeng Feng; Gang Li; Haixia Yu; Shaohui Wang; Xiaoqing Yi; Ling Lin
      Pages: 40 - 46
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Ximeng Feng, Gang Li, Haixia Yu, Shaohui Wang, Xiaoqing Yi, Ling Lin
      Noninvasive blood component analysis by spectroscopy has been a hotspot in biomedical engineering in recent years. Dynamic spectrum provides an excellent idea for noninvasive blood component measurement, but studies have been limited to the application of broadband light sources and high-resolution spectroscopy instruments. In order to remove redundant information, a more effective wavelength selection method has been presented in this paper. In contrast to many common wavelength selection methods, this method is based on sensing mechanism which has a clear mechanism and can effectively avoid the noise from acquisition system. The spectral difference coefficient was theoretically proved to have a guiding significance for wavelength selection. After theoretical analysis, the multi-band spectral difference coefficient-wavelength selection method combining with the dynamic spectrum was proposed. An experimental analysis based on clinical trial data from 200 volunteers has been conducted to illustrate the effectiveness of this method. The extreme learning machine was used to develop the calibration models between the dynamic spectrum data and hemoglobin concentration. The experiment result shows that the prediction precision of hemoglobin concentration using multi-band spectral difference coefficient-wavelength selection method is higher compared with other methods.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.10.063
      Issue No: Vol. 193 (2017)
       
  • Pressure-induced phase transition and fracture in α-MoO3 nanoribbons
    • Authors: Jose V. Silveira; Luciana L. Vieira; Acrisio L. Aguiar; Paulo T.C. Freire; Josue Mendes Filho; Oswaldo L. Alves; Antonio G. Souza Filho
      Pages: 47 - 53
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Jose V. Silveira, Luciana L. Vieira, Acrisio L. Aguiar, Paulo T.C. Freire, Josue Mendes Filho, Oswaldo L. Alves, Antonio G. Souza Filho
      MoO3 nanoribbons were studied under different pressure conditions ranging from 0 to 21GPa at room temperature. The effect of the applied pressure on the spectroscopic and morphologic properties of the MoO3 nanoribbons was investigated by means of Raman spectroscopy and scanning electron microscopy techniques. The pressure dependent Raman spectra of the MoO3 nanoribbons indicate that a structural phase transition occurs at 5GPa from the orthorhombic α-MoO3 phase (Pbnm) to the monoclinic MoO3-II phase (P2 1 /m), which remains stable up to 21GPa. Such phase transformation occurs at considerably lower pressure than the critical pressure for α-MoO3 microcrystals (12GPa). We suggested that the applanate morphology combined with the presence of crystalline defects in the sample play an important role in the phase transition of the MoO3 nanoribbons. Frequencies and linewidths of the Raman bands as a function of pressure also suggest a pressure-induced morphological change and the decreasing of the nanocrystal size. The observed spectroscopic changes are supported by electron microscopy images, which clearly show a pressure-induced morphologic change in MoO3 nanoribbons.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.053
      Issue No: Vol. 193 (2017)
       
  • Optimizing adsorption of blue pigment from wastewater by nano-porous
           modified Na-bentonite using spectrophotometry based on response surface
           method
    • Authors: Neshat Moradi; Shiva Salem; Amin Salem
      Pages: 54 - 62
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Neshat Moradi, Shiva Salem, Amin Salem
      This work highlighted the effective activation of bentonite paste to produce nano-porous powder for removal of cationic dye from wastewater. The effects of activation parameters such as soda and moisture contents, ageing time and temperature were analyzed using response surface methodology (RSM). The significance of independent variables and their interactions were tested by blending the obtained powders with wastewater and then the adsorption was evaluated, spectrophotometrically. The experiments were carried out by preparation of pastes according to response surface methodology and central composite design, which is the standard method, was used to evaluate the effects and interactions of four factors on the treatment efficiency. RSM was demonstrated as an appropriate approach for optimization of alkali activation. The optimal conditions obtained from the desirable responses were 5.0wt% soda and 45.0wt% moisture, respectively in which the powder activation was carried out at 150°C. In order to well understand the role of nano-structured material on dye removal, the adsorbents were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer–Emmett–Teller surface area measurement. Finally, the analysis clearly demonstrates that the dye removal onto prepared adsorbent is well fitted with Langmuir isotherm compared to the other isotherm models. The low cost of material and facile process support the further development for commercial application purpose.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.010
      Issue No: Vol. 193 (2017)
       
  • Structure elucidation and degradation kinetic study of Ofloxacin using
           surface enhanced Raman spectroscopy
    • Authors: Marwa R. El-Zahry; Bernhard Lendl
      Pages: 63 - 70
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Marwa R. El-Zahry, Bernhard Lendl
      A simple, fast and sensitive surface enhanced Raman spectroscopy (SERS) method for quantitative determination of fluoroquinolone antibiotic Ofloxacin (OFX) is presented. Also the stability behavior of OFX was investigated by monitoring the SERS spectra of OFX after various degradation processes. Acidic, basic and oxidative force degradation processes were applied at different time intervals. The forced degradation conditions were conducted and followed using SERS method utilizing silver nanoparticles (Ag NPs) as a SERS substrate. The Ag NPs colloids were prepared by reduction of silver nitrate using polyethyelene glycol (PEG) as a reducing and stabilizing agent. Validation tests were done in accordance with International Conference on Harmonization (ICH) guidelines. The calibration curve with a correlation coefficient (R =0.9992) was constructed as a relationship between the concentration range of OFX (100–500ng/ml) and SERS intensity at 1394cm−1 band. LOD and LOQ values were calculated and found to be 23.5ng/ml and 72.6ng/ml, respectively. The developed method was applied successfully for quantitation of OFX in different pharmaceutical dosage forms. Kinetic parameters were calculated including rate constant of the degradation of the studied antibiotic.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.007
      Issue No: Vol. 193 (2017)
       
  • Synthesis and fluorescence properties of some difluoroboron β-diketonate
           complexes and composite containing PMMA
    • Authors: Dongye Xing; Yanjun Hou; Haijun Niu
      Pages: 71 - 77
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Dongye Xing, Yanjun Hou, Haijun Niu
      A series of difluoroboron β-diketonate complexes, containing the indon-β-diketonate ligand carrying methyl or methoxyl substituents was synthesized. The crystal structures of the complexes were confirmed by single crystal X-ray diffraction studies. The fluorescence properties of compounds were studied in solution state, solid state and on PMMA polymer matrix. The photophysical data of compounds 2a–2d exhibited strong fluorescence and photostability under the ultraviolet light (Hg lamp). The complex 2b showed higher fluorescence intensity in solution state as compared to other complexes of the series. The complexes 2c and 2d showed higher fluorescence intensity in the solid state, which are ascribed to the stronger π–π interactions between ligands in the solid state. The introduction of methoxyl or methyl groups on the benzene rings enhanced the absorption intensity, emission intensity, quantum yields and fluorescence lifetimes due to their electron-donating nature. Furthermore, the complex 2b was doped into the PMMA to produce hybrid materials, where the PMMA matrix acted as sensitizer for the central boron ion to enhance the fluorescence emission intensity and quantum yields.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.001
      Issue No: Vol. 193 (2017)
       
  • The ground and low-lying excited states and feasibility of laser cooling
           for GaH+ and InH+ cations
    • Authors: Qing-Qing Zhang; Chuan-Lu Yang; Mei-Shan Wang; Xiao-Guang Ma; Wen-Wang Liu
      Pages: 78 - 86
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Qing-Qing Zhang, Chuan-Lu Yang, Mei-Shan Wang, Xiao-Guang Ma, Wen-Wang Liu
      The potential energy curves and transition dipole moments of 12Σ+ and 12Π states of GaH+ and InH+ cations are performed by employing ab initio calculations. Based on the potential energy curves, the rotational and vibrational energy levels of the two states are obtained by solving the Schrödinger equation of nuclear movement. The spectroscopic parameters are deduced with the obtained rovibrational energy levels. The spin-orbit coupling effect of the 2Π states for both the GaH+ and InH+ cations are also calculated. The feasibility of laser cooling of GaH+ and InH+ cations are examined by using the results of the electronic and spectroscopic properties. The highly diagonal Franck-Condon factors and appropriate radiative lifetimes are determined by using the potential energy curves and transition dipole moments for the 2Π1/2, 3/2 ↔12Σ+ transitions. The results indicate that the 2Π1/2, 3/2 ↔12Σ+ transitions of both GaH+ and InH+ cations are appropriate for the close cycle transition of laser cooling. The optical scheme of the laser cooling is constructed for the GaH+ and InH+ cations.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.009
      Issue No: Vol. 193 (2017)
       
  • Discrimination of geographical origin and detection of adulteration of
           kudzu root by fluorescence spectroscopy coupled with multi-way pattern
           recognition
    • Authors: Leqian Hu; Shuai Ma; Chunling Yin
      Pages: 87 - 94
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Leqian Hu, Shuai Ma, Chunling Yin
      In this work, fluorescence spectroscopy combined with multi-way pattern recognition techniques were developed for determining the geographical origin of kudzu root and detection and quantification of adulterants in kudzu root. Excitation-emission (EEM) spectra were obtained for 150 pure kudzu root samples of different geographical origins and 150 fake kudzu roots with different adulteration proportions by recording emission from 330 to 570nm with excitation in the range of 320–480nm, respectively. Multi-way principal components analysis (M-PCA) and multilinear partial least squares discriminant analysis (N-PLS-DA) methods were used to decompose the excitation-emission matrices datasets. 150 pure kudzu root samples could be differentiated exactly from each other according to their geographical origins by M-PCA and N-PLS-DA models. For the adulteration kudzu root samples, N-PLS-DA got better and more reliable classification result comparing with the M-PCA model. The results obtained in this study indicated that EEM spectroscopy coupling with multi-way pattern recognition could be used as an easy, rapid and novel tool to distinguish the geographical origin of kudzu root and detect adulterated kudzu root. Besides, this method was also suitable for determining the geographic origin and detection the adulteration of the other foodstuffs which can produce fluorescence.
      Graphical abstract image

      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.011
      Issue No: Vol. 193 (2017)
       
  • A highly selective fluorescence sensing platform for nanomolar Hg(II)
           detection based on cytosine derived quantum dot
    • Authors: Liang Luo; Ting Song; Haoqiang Wang; Qunhui Yuan; Shenghai Zhou
      Pages: 95 - 101
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Liang Luo, Ting Song, Haoqiang Wang, Qunhui Yuan, Shenghai Zhou
      Inspired by low toxicity and good biocompatibility of biomass derived quantum dot (QD), we herein developed a cytosine derived quantum dot, namely cyt-dot, via a one-step hydrothermal synthesis. The as-prepared cyt-dot emits blue fluorescence (FL) containing abundant oxygen (20.6at.%) and nitrogen (24.1at.%) contents. The cyt-dot based sensing platform shows exclusive selectivity for Hg(II) while being insensitive towards Fe(III) and Ag(I), which are important interference that usually cannot be ruled out. The detection limit for Hg(II) is of 11nM, which is very close to the guideline value of 10nM allowed by the U.S. Environmental Protection Agency in drinking water. In real water sample analyses, the present sensing platform can fulfil satisfied recoveries ranging from 100% to 108%. Besides, the acidity of solution has almost no effect on the sensing performance of the cyt-dot in a pH range of 5–8, suggesting its potential applications in sensing and bio-imaging.
      Graphical abstract image

      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.044
      Issue No: Vol. 193 (2017)
       
  • Ultrasensitive colorimetric immunoassay for hCG detection based on dual
           catalysis of Au@Pt core–shell nanoparticle functionalized by horseradish
           peroxidase
    • Authors: Weiguo Wang; Yake Zou; Jinwu Yan; Jing Liu; Huixiong Chen; Shan Li; Lei Zhang
      Pages: 102 - 108
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Weiguo Wang, Yake Zou, Jinwu Yan, Jing Liu, Huixiong Chen, Shan Li, Lei Zhang
      In this paper, an ultrasensitive colorimetric biosensor for human chorionic gonadotrophin (hCG) detection was designed from bottom-up method based on the dual catalysis of the horseradish peroxidase (HRP) and Au@Pt nanoparticles (NPs) relative to H2O2-TEM system. HRP and monoclonal mouse anti-hCG antibody (β-submit, mAb1) were co-immobilized onto the Au@Pt NP surface to improve catalytic efficiency and specificity, which formed a dual functionalized Au@Pt-HRP probe with the mean size of 42.8nm (D50). The colorimetric immunoassay was developed for the hCG detection, and the Au@Pt-HRP probe featured a higher sensitivity in the concentration range of 0.4–12.8IUL−1 with a low limit of detection (LOD) of 0.1IUL−1 compared with the LODs of 0.8IUL−1 for BA-ELISA and of 2.0IUL−1 for Au@Pt, which indicated that the Au@Pt-HRP probe possessed higher catalytic efficiency with 2.8-fold increase over Au@Pt and 33.8-fold increase over HRP. Also, the Au@Pt-HRP probe exhibited good precision and reproducibility, high specificity and acceptable accuracy with CV being less than 15%. The dual functionalized Au@Pt-HRP probe as a type of signal amplified method was firstly applied in the colorimetric immunoassay for the hCG detection.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.014
      Issue No: Vol. 193 (2017)
       
  • Recyclable colorimetric sensor of Cr3+ and Pb2+ ions simultaneously using
           a zwitterionic amino acid modified gold nanoparticles
    • Authors: Fuming Sang; Xin Li; Zhizhou Zhang; Jia Liu; Guofu Chen
      Pages: 109 - 116
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Fuming Sang, Xin Li, Zhizhou Zhang, Jia Liu, Guofu Chen
      In this work, a rapid, simple and sensitive colorimetric sensor for simultaneous (or respective) detection of Cr3+ and Pb2+ using tyrosine functionalized gold nanoparticles (AuNPsTyr) has been developed. Tyrosine, a natural and zwitterionic amino acid, could be as a reducing and capping agent to synthesise AuNPs and allow for the simultaneous and selective detection of Cr3+ and Pb2+. Upon the addition of Cr3+ or Pb2+ (a combination of them), the color of AuNPsTyr solution changes from red to blue grey and the characteristic surface plasmon resonance (SPR) band is red-shifted to 580nm due to the aggregation of AuNPs. Interestingly, the aggregated AuNPsTyr can be regnerated and recycled by removing Pb2+ and Cr3+. Even after 3 rounds, AuNPsTyr show almost the same A580nm /A520nm value for the assays of Pb2+ and Cr3+, indicating the good recyclability of the colorimetric sensor. The responding time (within 1min) and sensitivity of the colorimetric sensor are largely improved after the addition of 0.1M NaCl. Moreover, the AuNPsTyr aggregated by Cr3+ or Pb2+ (a combination of them) show excellent selectivity compared to other metal ions (Cr3+, Pb2+, Fe2+,Cu2+,Zn2+,Cr6+,Ni2+,Co2+,Hg2+,Mn2+,Mg2+,Ca2+,Cd2+). More importantly, the developed sensor manifests good stability at room temperature for 3months, which has been successfully used to determine Cr3+ and Pb2+ in the real water samples with a high sensitivity.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.048
      Issue No: Vol. 193 (2017)
       
  • Simplex optimization of the variables influencing the determination of
           pefloxacin by time-resolved chemiluminescence
    • Authors: José A. Murillo Pulgarín; Aurelia Alañón Molina; Elisa Jiménez García
      Pages: 117 - 124
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): José A. Murillo Pulgarín, Aurelia Alañón Molina, Elisa Jiménez García
      A new chemiluminescence (CL) detection system combined with flow injection analysis (FIA) for the determination of Pefloxacin is proposed. The determination is based on an energy transfer from Pefloxacin to terbium (III). The metal ion enhances the weak CL signal produced by the KMnO4/H2SO3/Pefloxacin system. A modified simplex method was used to optimize chemical and instrumental variables. The influence of the interaction of the permanganate, Tb (III), sodium sulphite and sulphuric acid concentrations, flow rate and injected sample volume was thoroughly investigated by using a modified simplex optimization procedure. The results revealed a strong direct relationship between flow rate and CL intensity throughout the studied range that was confirmed by a gamma test. The response factor for the CL emission intensity was used to assess performance in order to identify the optimum conditions for maximization of the response. Under such conditions, the CL response was proportional to the Pefloxacin concentration over a wide range. The detection limit as calculated according to Clayton's criterion 13.7μgL−1. The analyte was successfully determined in milk samples with an average recovery of 100.6±9.8%.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.002
      Issue No: Vol. 193 (2017)
       
  • Adsorption behavior and mechanism of acidic blue 25 dye onto
           cucurbit[8]uril: A spectral and DFT study
    • Authors: Hanhan Luo; Xiangyu Huang; Yuhan Luo; Zhuang Li; Lan Li; Chao Gao; Jinyan Xiong; Wei Li
      Pages: 125 - 132
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Hanhan Luo, Xiangyu Huang, Yuhan Luo, Zhuang Li, Lan Li, Chao Gao, Jinyan Xiong, Wei Li
      The acidic blue 25 (AB25) dye was efficiently adsorbed by CB [8]; the saturated adsorption capacity (qexp) reached 434.8mg/g and was far higher than those of previous reported adsorbents. The Langmuir and Freundich isotherms were used to fit the equilibrium data, and the results showed that the Freundlich isotherm seemed to agree better with the AB25 adsorption. The adsorption kinetics followed the pseudo-second-order model. Calculated thermodynamic parameters showed that the adsorption of AB25 onto CB [8] was a spontaneous and enthalpy-driven process. The adsorption mechanism was explored by N2 adsorption-desorption, TG, FT-IR, UV–vis as well as MD simulation and DFT calculations. TG analysis revealed that a new inclusion complex was produced, and FT-IR,UV–vis spectrum and DFT calculations verify its structure. In this inclusion complex, the AB25 dye molecule inserted into cavities of CB [8] from portal, and the sulfonate and phenyl groups stayed in the hydrophobic cavity. TDDFT calculations indicated that all excitation arisen from π→π* transition.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.006
      Issue No: Vol. 193 (2017)
       
  • Determination of zinc oxide content of mineral medicine calamine using
           near-infrared spectroscopy based on MIV and BP-ANN algorithm
    • Authors: Xiaodong Zhang; Long Chen; Yangbo Sun; Yu Bai; Bisheng Huang; Keli Chen
      Pages: 133 - 140
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Xiaodong Zhang, Long Chen, Yangbo Sun, Yu Bai, Bisheng Huang, Keli Chen
      Near-infrared (NIR) spectroscopy has been widely used in the analysis fields of traditional Chinese medicine. It has the advantages of fast analysis, no damage to samples and no pollution. In this research, a fast quantitative model for zinc oxide (ZnO) content in mineral medicine calamine was explored based on NIR spectroscopy. NIR spectra of 57 batches of calamine samples were collected and the first derivative (FD) method was adopted for conducting spectral pretreatment. The content of ZnO in calamine sample was determined using ethylenediaminetetraacetic acid (EDTA) titration and taken as reference value of NIR spectroscopy. 57 batches of calamine samples were categorized into calibration and prediction set using the Kennard-Stone (K-S) algorithm. Firstly, in the calibration set, to calculate the correlation coefficient (r) between the absorbance value and the ZnO content of corresponding samples at each wave number. Next, according to the square correlation coefficient (r 2) value to obtain the top 50 wave numbers to compose the characteristic spectral bands (4081.8–4096.3, 4188.9–4274.7, 4335.4, 4763.6,4794.4–4802.1, 4809.9, 4817.6–4875.4cm−1), which were used to establish the quantitative model of ZnO content using back propagation artificial neural network (BP-ANN) algorithm. Then, the 50 wave numbers were operated by the mean impact value (MIV) algorithm to choose wave numbers whose absolute value of MIV greater than or equal to 25, to obtain the optimal characteristic spectral bands (4875.4–4836.9, 4223.6–4080.9cm−1). And then, both internal cross and external validation were used to screen the number of hidden layer nodes of BP-ANN. Finally, the number 4 of hidden layer nodes was chosen as the best. At last, the BP-ANN model was found to enjoy a high accuracy and strong forecasting capacity for analyzing ZnO content in calamine samples ranging within 42.05–69.98%, with relative mean square error of cross validation (RMSECV) of 1.66% and coefficient of determination (R 2) of 95.75% in internal cross and relative mean square error of prediction (RMSEP) of 1.98%, R 2 of 97.94% and ratio of performance to deviation (RPD) of 6.11 in external validation.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.019
      Issue No: Vol. 193 (2017)
       
  • Synthesis and studies of axial chiral bisbenzocoumarins:
           Aggregation-induced emission enhancement properties and
           aggregation-annihilation circular dichroism effects
    • Authors: Shaojin Chen; Wei Liu; Zhaohai Ge; Wenxuan Zhang; Kunpeng Wang; Zhiqiang Hu
      Pages: 141 - 146
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Shaojin Chen, Wei Liu, Zhaohai Ge, Wenxuan Zhang, Kunpeng Wang, Zhiqiang Hu
      Axial chiral bisbenzocoumarins were synthesized for the first time by converting naphthanol units in 1,1′-binaphthol (BINOL) molecule to the benzocoumarin rings. The substitute groups on 3,3′-positions of bisbenzocoumarins showed significant influence on their aggregation-induced emission enhancement (AEE) properties. It was also found that BBzC1 with ester groups on 3,3′-positions exhibit an abnormal aggregation-annihilation circular dichroism (AACD) phenomenon, which could be caused by the decrease of the dihedral angle between adjacent benzocoumarin rings in the aggregation state. The single crystal structure of BBzC1 showed that the large dihedral angle in molecule prohibited the strong π-π stacking interactions, which could be main factors for its AEE properties.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.005
      Issue No: Vol. 193 (2017)
       
  • Investigation of anticancer properties of caffeinated complexes via
           computational chemistry methods
    • Authors: Koray Sayin; Ayhan Üngördü
      Pages: 147 - 155
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Koray Sayin, Ayhan Üngördü
      Computational investigations were performed for 1,3,7-trimethylpurine-2,6-dione, 3,7-dimethylpurine-2,6-dione, their Ru(II) and Os(III) complexes. B3LYP/6-311++G(d,p)(LANL2DZ) level was used in numerical calculations. Geometric parameters, IR spectrum, 1H-, 13C and 15N NMR spectrum were examined in detail. Additionally, contour diagram of frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) maps, MEP contour and some quantum chemical descriptors were used in the determination of reactivity rankings and active sites. The electron density on the surface was similar to each other in studied complexes. Quantum chemical descriptors were investigated and the anticancer activity of complexes were more than cisplatin and their ligands. Additionally, molecular docking calculations were performed in water between related complexes and a protein (ID: 3WZE). The most interact complex was found as Os complex. The interaction energy was calculated as 342.9kJ/mol.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.013
      Issue No: Vol. 193 (2017)
       
  • Different β-alanine dimeric forms in trifluoromethanesulfonic acid salts.
           XRD and vibrational studies
    • Authors: Łukasz Wołoszyn; Maria M. Ilczyszyn
      Pages: 156 - 168
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Łukasz Wołoszyn, Maria M. Ilczyszyn
      Two new crystalline salts: β-alaninium trifluoromethanesulfonate (β-AlaOTf) and bis(β-alanine) trifluoromethanesulfonate (β-2AlaOTf) were obtained. The former one contains diprotonated β-alanine dimer, the latter one monoprotonated β-alanine dimer. Both compounds were studied by single crystal XRD, vibrational (IR and Raman) spectroscopy and calorimetric method. The quantum-mechanical calculations (DFT/B3LYP/6-311++G(2d,2p)) for the diprotonated dimer were carried out. The β-AlaOTf salt crystallizes in the P 1 ¯ space group of triclinic system (Z =2), the β-2AlaOTf in the P21/m space group of monoclinic system (Z =2). The vibrational data for the studied compounds are discussed in relation to their crystal structure, and provide insight into the character of hydrogen bonds and β-alanine protonation. The studied crystals do not exhibit phase transitions in the solid state.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.018
      Issue No: Vol. 193 (2017)
       
  • Synergistic cytotoxicity and mechanism of caffeine and lysozyme on
           hepatoma cell line HepG2
    • Authors: Hongchao Yang; Jingjuan Li; Lin Cui; Yanqing Ren; Liying Niu; Xinguo Wang; Yun Huang; Lijian Cui
      Pages: 169 - 174
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Hongchao Yang, Jingjuan Li, Lin Cui, Yanqing Ren, Liying Niu, Xinguo Wang, Yun Huang, Lijian Cui
      The influences of caffeine, lysozyme and the joint application of them on the hepatoma cell line HepG2 proliferation inhibition and cell apoptosis were observed by 3-(4, 5-dimethyl-2-thiazyl)-2, 5-diphenyl-2H-tetrazolium bromide assay and Hoechst 33342, which showed the proliferation inhibition rate of the joint application on HepG2 cells was 47.21%, significantly higher than caffeine or lysozyme, and the joint application promoted the apoptosis of HepG2 cells obviously. Van't Hoff classical thermodynamics formula, the Föster theory of non-radiation energy transfer and fluorescence phase diagram were used to manifest that the process of lysozyme binding to caffeine followed a two-state model, which was spontaneous at low temperature driven by enthalpy change, and the predominant intermolecular force was hydrogen bonding or Van der Waals force to stabilize caffeine-lysozyme complex with the distance 5.86nm. The attenuated total reflection-Fourier transform infrared spectra indicated that caffeine decreased the relative contents of α-helix and β-turn, which inferred the structure of lysozyme tended to be “loose”. Synchronous fluorescence spectra and ultraviolet spectra supported the above conclusion. The amino acid residues in the cleft of lysozyme were exposed and electropositivity was increased attributing to the loose structure, which were conducive to increasing caffeine concentration on the HepG2 cell surface by electrostatic interaction to show synergistic effect.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.020
      Issue No: Vol. 193 (2017)
       
  • Excitation of triplet states of hypericin in water mediated by hydrotropic
           cromolyn sodium salt
    • Authors: Peter Keša; Daniel Jancura; Júlia Kudláčová; Eva Valušová; Marián Antalík
      Pages: 185 - 191
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Peter Keša, Daniel Jancura, Júlia Kudláčová, Eva Valušová, Marián Antalík
      Hypericin (Hyp) is a hydrophobic pigment found in plants of the genus Hypericum which exhibits low levels of solubility in water. This work shows that the solubility of Hyp can be significantly increased through the addition of cromolyn disodium salt (DSCG). Performed studies using UV–VIS absorption and fluorescence spectroscopies demonstrate that Hyp remains in a predominantly biologically photodynamic active monomeric form in the presence of DSCG at concentrations ranging from 4.6×10−3 to 1.2×10−1 mol·L−1. The low association constant between Hyp and DSCG (K a =71.7±2M−1), and the polarity value of 0.3 determined for Hyp in a DSCG-water solution, lead to a suggestion that the monomerization of Hyp in aqueous solution can be explained as a result of the hydrotropic effect of DSCG. This hydrotropic effect is most likely a result of interactions between two relative rigid aromatic rings of DSCG and a delocalized charge on the surface of the Hyp molecule. The triplet-triplet (T-T) electronic transition observed in is Hyp in the presence of DSCG suggests a possible production of reactive oxygen species once Hyp is irradiated with visible light in a DSCG aqueous solution.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.004
      Issue No: Vol. 193 (2017)
       
  • Effect of auxiliary group for p-type organic dyes in NiO-based
           dye-sensitized solar cells: The first principal study
    • Authors: Juan Li; Shijie Zhang; Di Shao; Zhenqing Yang; Wansong Zhang
      Pages: 192 - 196
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Juan Li, Shijie Zhang, Di Shao, Zhenqing Yang, Wansong Zhang
      Auxiliary acceptor groups play a crucial role in D-A-π-A structured organic dyes. In this paper, we designed three D-A-π-A structured organic molecules based on the prototype dye QT-1, named ME18–ME20, and further investigated their electronic and optical properties with density functional theory (DFT) and time-dependent DFT (TDDFT). The calculated results indicate that the scope and intensity of dyes' absorption spectra have some outstanding changes by inserting auxiliary groups. ME20 has not only 152nm redshifts to long wave orientation, but also 78% increased oscillator strength compared to QT-1, and its absorption spectrum broadens region even up to 1400nm. Then, we studied the reason that the effect of the introduced different auxiliary acceptor groups in these dyes through their ground states geometries and energy levels, electron transfer and recombination rate.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.012
      Issue No: Vol. 193 (2017)
       
  • pH-Dependent reversible crystal transformation of
           1-carboxymethyl-1-methyl-pyrrolidinium bromides and their spectroscopic
           fingerprint
    • Authors: Ya-yan Tong; Heng Zhang; Liang-liang Chang; Xiao-peng Xuan
      Pages: 197 - 202
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Ya-yan Tong, Heng Zhang, Liang-liang Chang, Xiao-peng Xuan
      In this work, two 1-carboxymethyl-1-methyl-pyrrolidinium bromides (N-methylpyrrolidine betaine hydrobromides) with the stoichiometry of betaine:hydrobromic acid as 1:1 and 2:1, denoted as CMPRHBr-I and CMPRHBr-II, respectively, were prepared and crystallographically determined. The large difference in these two structures is the type of hydrogen bonds, resulting in the different thermal stability. A strong OH⋯Br hydrogen bond was observed in CMPRHBr-I, whereas O⋯H⋯O hydrogen bond in CMPRHBr-II. Both these two crystals can mutually transform by changing the pH value of the aqueous solution. Vibrational spectroscopic studies shows that these two structures can be easily distinguished by the characteristic bands such as νCO stretching vibration and the D-type bands. Our studies indicate that it should be cautious of the structural change as this type of organic salts was purified and recrystallized.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.11.054
      Issue No: Vol. 193 (2017)
       
  • Spectroscopic parameters, vibrational levels, transition dipole moments
           
    • Authors: Yuan Yin; Deheng Shi; Jinfeng Sun; Zunlue Zhu
      Pages: 203 - 211
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Yuan Yin, Deheng Shi, Jinfeng Sun, Zunlue Zhu
      This work calculates the potential energy curves of 9 Λ-S and 28Ω states of the NCl+ cation. The technique employed is the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. The Λ-S states are X2Π, 12Σ+, 14Π, 14Σ+, 14Σ−, 24Π, 14Δ, 16Σ+, and 16Π, which are yielded from the first two dissociation channels of NCl+ cation. The Ω states are generated from these Λ-S states. The 14Π, 14Δ, 16Σ+, and 16Π states are inverted with the spin-orbit coupling effect included. The 14Σ+, 16Σ+, and 16Π states are very weakly bound, whose well depths are only several-hundredcm−1. One avoided crossing of PECs occurs between the 12Σ+ and 22Σ+ states. To improve the quality of potential energy curves, core-valence correlation and scalar relativistic corrections are included. The potential energies are extrapolated to the complete basis set limit. The spectroscopic parameters and vibrational levels are calculated. The transition dipole moments are computed. The Franck-Condon factors, Einstein coefficients, and radiative lifetimes of many transitions are determined. The spectroscopic approaches are proposed for observing these states according to the transition probabilities. The spin-orbit coupling effect on the spectroscopic and vibrational properties is evaluated. The spectroscopic parameters, vibrational levels, transition dipole moments, as well as transition probabilities reported in this paper could be considered to be very reliable.
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      PubDate: 2017-12-12T09:05:29Z
      DOI: 10.1016/j.saa.2017.12.035
      Issue No: Vol. 193 (2017)
       
  • Evaluation of TeO2 content on the optical and spectroscopic properties of
           Yb3+-doped calcium borotellurite glasses
    • Authors: A.M.O. Lima; J.F. Gomes; F.L. Hegeto; A.N. Medina; A. Steimacher; M.J. Barboza
      Pages: 212 - 218
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): A.M.O. Lima, J.F. Gomes, F.L. Hegeto, A.N. Medina, A. Steimacher, M.J. Barboza
      This paper reports the synthesis and the characterization of Yb3+-doped calcium borotellurite (CaBTeX) glasses with composition 10CaF2–(29.5−0.4x)CaO–(60−0.6x)B2O3–xTeO2–0.5Yb2O3 (x=10, 16, 22, 31 and 54mol%). The results of XRD confirm the amorphous character of all the samples. The density, molar volume, refractive index and electronic polarizability values show an increase with TeO2 content. Otherwise, the optical band gap energy shows a decrease with the increase of TeO2 content. The replacement of CaO and B2O3 by TeO2 changes the glass structure, which decreases the excited Yb3+/cm3 and, consequently, the luminescence intensity. The temperature dependence of luminescence was studied for all the samples up to 420K. The fluorescence lifetime does not change significantly due to TeO2 addition. In addition, absorption and emission cross section were calculated and present high values as compared to other tellurite and phosphate glasses.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.032
      Issue No: Vol. 193 (2017)
       
  • Time-resolved laser fluorescence spectroscopy of organic ligands by
           europium: Fluorescence quenching and lifetime properties
    • Authors: A. Nouhi; H. Hajjoul; R. Redon; J.P. Gagné; S. Mounier
      Pages: 219 - 225
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): A. Nouhi, H. Hajjoul, R. Redon, J.P. Gagné, S. Mounier
      Time-resolved Laser Fluorescence Spectroscopy (TRLFS) has proved its usefulness in the fields of biophysics, life science and geochemistry to characterize the fluorescence probe molecule with its chemical environment. The purpose of this study is to demonstrate the applicability of this powerful technique combined with Steady-State (S-S) measurements. A multi-mode factor analysis, in particular CP/PARAFAC, was used to analyze the interaction between Europium (Eu) and Humic substances (HSs) extracted from Saint Lawrence Estuary in Canada. The Saint Lawrence system is a semi-enclosed water stream with connections to the Atlantic Ocean and is an excellent natural laboratory. CP/PARAFAC applied to fluorescence S-S data allows introspecting ligands–metal interactions and the one-site 1:1 modeling gives information about the stability constants. From the spectral signatures and decay lifetimes data given by TRLFS, one can deduce the fluorescence quenching which modifies the fluorescence and discuss its mechanisms. Results indicated a relatively strong binding ability between europium and humic substances samples (LogK value varies from 3.38 to 5.08 at pH 7.00). Using the Stern-Volmer plot, it has been concluded that static and dynamic quenching takes places in the case of salicylic acid and europium interaction while for HSs interaction only a static quenching is observed.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.028
      Issue No: Vol. 193 (2017)
       
  • Two sugar-rhodamine “turn-on” fluorescent probes for the
           selective detection of Fe3+
    • Authors: Qing Chen; Zhijie Fang
      Pages: 226 - 234
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Qing Chen, Zhijie Fang
      Two new sugar-rhodamine fluorescent probes (RDG1 and RDG2) have been synthesized and characterized by 1H NMR, 13C NMR and HRMS. Their UV–Vis, fluorescence spectra and fluorescence-response to Fe3+ are investigated and discussed. RDG1 had a very nice linear relationship between UV absorbance and Fe3+ concentration with the correlation coefficient as high as 0.997 and the detection limit is 3.46×10−6 M. Upon the addition of Fe3+, the spirolactam ring of RDG1 was opened and a 1:1 metal ligand complex was formed from Job's plot. The results showed that RDG1 can be used as an effective fluorescent probe for selective detection of Fe3+ in water. RDG2 was incorporated the well-known rhodamine group and a water-soluble d-glucose group within one molecule and can be used for detecting Fe3+ in natural water as a selective fluorescent sensor. The addition of Fe3+ into RDG2 resulted in a strongly enhanced fluorescence as well as color change of solution from colorless to pink. Job's plot of RDG2 indicated 1:1 stoichiometry of RDG2-Fe3+. RDG2 can serve as a probe for Fe3+ between pH=4.0 to 7.0 and it's detection limit is 2.09×10−6 M. The OFF-ON fluorescent mechanisms of RDG1-Fe3+ and RDG2-Fe3+ are proposed.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.023
      Issue No: Vol. 193 (2017)
       
  • Aggregation and metal-complexation behaviour of THPP porphyrin in
           ethanol/water solutions as function of pH
    • Authors: Marco Zannotti; Rita Giovannetti; Babak Minofar; David Řeha; Lydie Plačková; Chiara A. D'Amato; Elena Rommozzi; Hanna V. Dudko; Nuerguli Kari; Marco Minicucci
      Pages: 235 - 248
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Marco Zannotti, Rita Giovannetti, Babak Minofar, David Řeha, Lydie Plačková, Chiara A. D'Amato, Elena Rommozzi, Hanna V. Dudko, Nuerguli Kari, Marco Minicucci
      The effect of pH change on 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (THPP) with its aggregation as function of water-ethanol mixture was studied with UV–vis, fluorescence, Raman and computational analysis. In neutral pH, THPP was present as free-base and, increasing the water amount, aggregation occurred with the formation of H- and J-aggregates. The aggregation constant and the concentration of dimers were calculated, other information about the dimer aggregation were evaluated by computational study. In acidic pH, by the insertions of two hydrogens in the porphyrin rings, the porphyrin changed its geometry with a ring deformation confirmed by red-shifted spectrum and quenching in fluorescence; at this low pH, increasing the water amount, the acidic form (THPPH2)2+ resulted more stable due to a polar environment with stronger interaction by hydrogen bonding. In basic pH, reached by NH4OH, THPP porphyrin was able to react with alkali metals in order to form sitting-atop complex (M2THPP) confirmed by the typical absorption spectrum of metallo-porphyrin, Raman spectroscopy and by computational analysis.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.021
      Issue No: Vol. 193 (2017)
       
  • TDDFT calculations and photoacoustic spectroscopy experiments used to
           identify phenolic acid functional biomolecules in Brazilian tropical
           fruits in natura
    • Authors: M. Lourenço Neto; K.L. Agra; J. Suassuna Filho; F.E. Jorge
      Pages: 249 - 257
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): M. Lourenço Neto, K.L. Agra, J. Suassuna Filho, F.E. Jorge
      Time-dependent density functional theory (TDDFT) calculations of electronic transitions have been widely used to determine molecular structures. The excitation wavelengths and oscillator strengths obtained with the hybrid exchange-correlation functional B3LYP in conjunction with the ADZP basis set are employed to simulate the UV–Vis spectra of eight phenolic acids. Experimental and theoretical UV–Vis spectra reported previously in the literature are compared with our results. The fast, sensitive and non-destructive technique of photoacoustic spectroscopy (PAS) is used to determine the UV–Vis spectra of four Brazilian tropical fresh fruits in natura. Then, the PAS along with the TDDFT results are for the first time used to investigate and identify the presence of phenolic acids in the fruits studied in this work. This theoretical method with this experimental technique show to be a powerful and cheap tool to detect the existence of phenolic acids in fruits, vegetables, cereals, and grains. Comparison with high performance liquid chromatography results, when available, is also carried out.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.036
      Issue No: Vol. 193 (2017)
       
  • Spectral study on conformation switchable cationic calix[4]carbazole
           serving as curcumin container, stabilizer and sustained-delivery carrier
    • Authors: Liang Zhao; Le Kang; Yan Chen; Gang Li; Lan Wang; Chun Hu; Peng Yang
      Pages: 276 - 282
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Liang Zhao, Le Kang, Yan Chen, Gang Li, Lan Wang, Chun Hu, Peng Yang
      A fluorescent 2,7-dimethoxy-substituted calix[4]carbazole (1) is facilely synthesized. The spectral behaviors of both the guest-induced switchable conformation of 1 and its abilities serving as the stabilizer and molecular carrier of curcumin are investigated. UV–vis, fluorescence and NMR spectral results show that upon binding to curcumin, the 1,3-alternate conformation of 1 is converted to be the cone one. The relative high association constant (6.4×106 M−1) of 1 binding to curcumin enables it to stabilize the curcumin, to suppress its degradation, and to sustainably deliver it into the EYPC vesicles within 20h. Moreover, the cytotoxicity assay shows that 1 does not interfere the antiproliferative activities of curcumin. All these properties endow 1 the potential capability of serving as the molecular drug carrier. Our current result may pave the way looking for more efficient fluorescent calixcarbazoles and thereof spectral utilities.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.037
      Issue No: Vol. 193 (2017)
       
  • Oligothiophene-based colorimetric and ratiometric fluorescence
           dual-channel cyanide chemosensor: Sensing ability, TD-DFT calculations and
           its application as an efficient solid state sensor
    • Authors: Linxin Lan; Tianduo Li; Tao Wei; He Pang; Tao Sun; Enhua Wang; Haixia Liu; Qingfen Niu
      Pages: 289 - 296
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Linxin Lan, Tianduo Li, Tao Wei, He Pang, Tao Sun, Enhua Wang, Haixia Liu, Qingfen Niu
      An oligothiophene-based colorimetric and ratiometric fluorescence dual-channel cyanide chemosensor 3 T-2CN was reported. Sensor 3 T-2CN showed both naked-eye recognition and ratiometric fluorescence response for CN− with an excellent selectivity and high sensitivity. The sensing mechanism based on the nucleophilic attack of CN− on the vinyl CC bond has been successfully confirmed by the optical measurements, 1H NMR titration, FT-IR spectra as well as the DFT/TD-DFT calculations. Moreover, the detection limit was calculated to be 0.19μM, which is much lower than the maximum permission concentration in drinking water (1.9μM). Importantly, test strips (filter paper and TLC plates) containing 3 T-2CN were fabricated, which could act as a practical and efficient solid state optical sensor for CN− in field measurements.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.039
      Issue No: Vol. 193 (2017)
       
  • The application of artificial neural networks and support vector
           regression for simultaneous spectrophotometric determination of commercial
           eye drop contents
    • Authors: Maryam Valizadeh; Mahmoud Reza Sohrabi
      Pages: 297 - 304
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Maryam Valizadeh, Mahmoud Reza Sohrabi
      In the present study, artificial neural networks (ANNs) and support vector regression (SVR) as intelligent methods coupled with UV spectroscopy for simultaneous quantitative determination of Dorzolamide (DOR) and Timolol (TIM) in eye drop. Several synthetic mixtures were analyzed for validating the proposed methods. At first, neural network time series, which one type of network from the artificial neural network was employed and its efficiency was evaluated. Afterwards, the radial basis network was applied as another neural network. Results showed that the performance of this method is suitable for predicting. Finally, support vector regression was proposed to construct the Zilomole prediction model. Also, root mean square error (RMSE) and mean recovery (%) were calculated for SVR method. Moreover, the proposed methods were compared to the high-performance liquid chromatography (HPLC) as a reference method. One way analysis of variance (ANOVA) test at the 95% confidence level applied to the comparison results of suggested and reference methods that there were no significant differences between them. Also, the effect of interferences was investigated in spike solutions.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.11.056
      Issue No: Vol. 193 (2017)
       
  • Fluorescent carbon dots nanosensor for label-free determination of vitamin
           B12 based on inner filter effect
    • Authors: Longhua Ding; Hongmei Yang; Shenguang Ge; Jinghua Yu
      Pages: 305 - 309
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Longhua Ding, Hongmei Yang, Shenguang Ge, Jinghua Yu
      A simple and effective fluorescent assay for the determination of vitamin B12 was developed. In this study, carbon dots (CDs) were prepared by one-pot hydrothermal method and directly used as a fluorophore in the inner filter effect (IFE). Both of the maximum absorption peak of vitamin B12 and excitation maxima of CDs are located at 360nm, hence, the excited light of CDs can be absorbed by vitamin B12, resulting in the fluorescence reduction of CDs. And the fluorescence intensity of CDs decreases with the increasing concentration of vitamin B12. This IFE-based sensing strategy shows a good linear relationship between the normalized fluorescence intensity and the concentration of vitamin B12 ranging from 0 to 60μM, with a limit of detection (LOD) of 0.1μM at a signal-to-noise ratio of 3. Furthermore, this proposed approach was successfully applied to vitamin B12 sensing in injections. This IFE sensing platform based on various fluorescent nanomaterials has a high promise for the detection of other biomolecules due to its inherent convenience.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.015
      Issue No: Vol. 193 (2017)
       
  • Novel kinetic spectrophotometric method for estimation of certain
           biologically active phenolic sympathomimetic drugs in their bulk powders
           and different pharmaceutical formulations
    • Authors: Mahmoud A. Omar; Khalid M. Badr El-Din; Hesham Salem; Osama H. Abdelmageed
      Pages: 310 - 317
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Mahmoud A. Omar, Khalid M. Badr El-Din, Hesham Salem, Osama H. Abdelmageed
      A simple, selective and sensitive kinetic spectrophotometric method was described for estimation of four phenolic sympathomimetic drugs namely; terbutaline sulfate, fenoterol hydrobromide, isoxsuprine hydrochloride and etilefrine hydrochloride. This method is depended on the oxidation of the phenolic drugs with Folin-Ciocalteu reagent in presence of sodium carbonate. The rate of color development at 747–760nm was measured spectrophotometrically. The experimental parameters controlling the color development were fully studied and optimized. The reaction mechanism for color development was proposed. The calibration graphs for both the initial rate and fixed time methods were constructed, where linear correlations were found in the general concentration ranges of 3.65×10−6–2.19×10−5 molL−1 and 2–24.0μgmL−1 with correlation coefficients in the following range 0.9992–0.9999, 0.9991–0.9998 respectively. The limits of detection and quantitation for the initial rate and fixed time methods were found to be in general concentration range 0.109–0.273, 0.363–0.910 and 0.210–0.483, 0.700–1.611μgmL−1 respectively. The developed method was validated according to ICH and USP 30 –NF 25 guidelines. The suggested method was successfully implemented to the estimation of these drugs in their commercial pharmaceutical formulations and the recovery percentages obtained were ranged from 97.63%±1.37 to 100.17%±0.95 and 97.29%±0.74 to 100.14±0.81 for initial rate and fixed time methods respectively. The data obtained from the analysis of dosage forms were compared with those obtained by reported methods. Statistical analysis of these results indicated no significant variation in the accuracy and precision of both the proposed and reported methods.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.045
      Issue No: Vol. 193 (2017)
       
  • NMR diffusion and relaxation studies of 2-nitroimidazole and albumin
           interactions
    • Authors: Dj Wijesekera; Scott A. Willis; Abhishek Gupta; Allan M. Torres; Gang Zheng; William S. Price
      Pages: 318 - 323
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Dj Wijesekera, Scott A. Willis, Abhishek Gupta, Allan M. Torres, Gang Zheng, William S. Price
      Nitroimidazole derivatives are of current interest in the development of hypoxia targeting agents and show potential in the establishment of quantitative measures of tumor hypoxia. In this study, the binding of 2-nitroimidazole to albumin was probed using NMR diffusion and relaxation measurements. Binding studies were conducted at three different protein concentrations (0.23, 0.30 and 0.38mM) with drug concentrations ranging from 0.005–0.16M at 298K. Quantitative assessments of the binding model were made by evaluating the number of binding sites, n, and association constant, K. These were determined to be 21±3 and 53±4M−1, respectively.
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      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.016
      Issue No: Vol. 193 (2017)
       
  • A novel fluorescein-based “turn-on” probe for the detection of
           hydrazine and its application in living cells
    • Authors: Wen-Zhi Xu; Wei-Yan Liu; Ting-Ting Zhou; Yu-Tao Yang; Wei Li
      Pages: 324 - 329
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Wen-Zhi Xu, Wei-Yan Liu, Ting-Ting Zhou, Yu-Tao Yang, Wei Li
      We constructed a novel probe for hydrazine detection based on ICT and PET mechanism. Phthalimide and acetyl ester groups were used as the recognition units. Addition of hydrazine produced a turn-on fluorescence at 525nm along with the fluorescent color change from dark to yellow. The probe could selectively detect hydrazine over other related interfering species. The detection limit of the probe for hydrazine was calculated to be 0.057μM which was lower than the EPA standard (0.320μM). Furthermore, the probe could also be applied for the imaging of hydrazine in living cells.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.040
      Issue No: Vol. 193 (2017)
       
  • Hydrazinylpyridine based highly selective optical sensor for aqueous
           source of carbonate ions: Electrochemical and DFT studies
    • Authors: Vikram Thimaradka; Srikala Pangannaya; Makesh Mohan; Darshak R. Trivedi
      Pages: 330 - 337
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Vikram Thimaradka, Srikala Pangannaya, Makesh Mohan, Darshak R. Trivedi
      A series of new receptors PDZ1–3 based on 2-(arylidenehydrazinyl)pyridines have been designed and synthesized for the detection of biologically and environmentally important ions. The colorimetric detection of CO3 2− using neutral organic receptor PDZ-1 has been achieved with characteristic visual colour change from yellow to green accompanied by a large redshift of 215nm in absorption maxima. UV–Vis spectroscopic and cyclic voltammetric studies reveal the stoichiometry of binding and electrochemistry of host-guest complex formation. The binding constant was found to be 0.77×104 M−2. In addition, electrochemical studies provide an insight into the stability of the complex. DFT studies performed on the PDZ-1 and PDZ-1 −CO3 2− complex reveal the binding mechanism involved in the anion detection process. PDZ-1 is highly selective for carbonate and does not show any colorimetric response towards any other anions or cations, while PDZ-2 and PDZ-3 remain inactive in the ion detection process. The limit of detection (LOD) and limit of quantification (LOQ) of PDZ-1 for carbonate was found to be 0.11mM and 0.36mM respectively. Considerable binding constant and limit of detection make PDZ-1 to be used as a real time sensor for the detection of carbonate in environmental and biological samples.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.041
      Issue No: Vol. 193 (2017)
       
  • Temperature- and pressure-dependent infrared spectroscopy of
           1-butyl-3-methylimidazolium trifluoromethanesulfonate: A dipolar coupling
           theory analysis
    • Authors: Christopher M. Burba; Hai-Chou Chang
      Pages: 338 - 343
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Christopher M. Burba, Hai-Chou Chang
      Continued growth and development of ionic liquids requires a thorough understanding of how cation and anion molecular structure defines the liquid structure of the materials as well as the various properties that make them technologically useful. Infrared spectroscopy is frequently used to assess molecular-level interactions among the cations and anions of ionic liquids because the intramolecular vibrational modes of the ions are sensitive to the local potential energy environments in which they reside. Thus, different interaction modes among the ions may lead to different spectroscopic signatures in the vibrational spectra. Charge organization present in ionic liquids, such as 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4mim]CF3SO3), is frequently modeled in terms of a quasicrystalline structure. Highly structured quasilattices enable the dynamic coupling of vibrationally-induced dipole moments to produce optical dispersion and transverse optical-longitudinal optical (TO-LO) splitting of vibrational modes of the ionic liquid. According to dipolar coupling theory, the degree of TO-LO splitting is predicted to have a linear dependence on the number density of the ionic liquid. Both temperature and pressure will affect the number density of the ionic liquid and, therefore, the amount of TO-LO splitting for this mode. Therefore, we test these relationships through temperature- and pressure-dependent FT-IR spectroscopic studies of [C4mim]CF3SO3, focusing on the totally symmetric SO stretching mode for the anion, νs(SO3). Increased temperature decreases the amount of TO-LO splitting for νs(SO3), whereas elevated pressure is found to increase the amount of band splitting. In both cases, the experimental observations follow the general predictions of dipolar coupling theory, thereby supporting the quasilattice model for this ionic liquid.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.026
      Issue No: Vol. 193 (2017)
       
  • Environment dependent enhanced photoluminescence and Boolean logic gates
           like behavior of Bi2O3 and Ag:Bi2O3 nanostructures
    • Authors: S. Hariharan; B. Karthikeyan
      Pages: 344 - 348
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): S. Hariharan, B. Karthikeyan
      In the evolution of nanotechnology research for smart and precise sensor fabrication, here we report the implementation of simple logic gate operations performing by luminescent nanostructures in biomolecule environment based on photoluminescence (PL) technique. This present work deals with the luminescence property of α -Bi2O3 and Ag modified α -Bi2O3 nanostructures for d-glucose and Bovine serum albumin (BSA) sensing applications. These nanostructures are prepared by simple co-precipitation method and their morphology are examined using transmission electron microscope (TEM). We explore the PL characteristics of the prepared nanostructures and observe their change in PL intensity in the presence of d-glucose and BSA molecules. Enhancement in PL intensity is observed in the presence of d-glucose and BSA. Based on the PL response of prepared nanostructures in the biomolecule environment, we demonstrate biophotonic logic gates including YES, PASS 0, OR and INHIBIT gates.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.022
      Issue No: Vol. 193 (2017)
       
  • Highly selective apo-arginase based method for sensitive enzymatic assay
           of manganese (II) and cobalt (II) ions
    • Authors: Nataliya Stasyuk; Galina Gayda; Andriy Zakalskiy; Oksana Zakalska; Abdelhamid Errachid; Mykhailo Gonchar
      Pages: 349 - 356
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Nataliya Stasyuk, Galina Gayda, Andriy Zakalskiy, Oksana Zakalska, Abdelhamid Errachid, Mykhailo Gonchar
      A novel enzymatic method of manganese (II) and cobalt (II) ions assay, based on using apo-enzyme of Mn2+-dependent recombinant arginase I (arginase) and 2,3-butanedione monoxime (DMO) as a chemical reagent is proposed. The principle of the method is the evaluation of the activity of L-arginine-hydrolyzing of arginase holoenzyme after the specific binding of Mn2+ or Co2+ with apo-arginase. Urea, which is the product of enzymatic hydrolysis of L-arginine (Arg), reacts with DMO and the resulted compound is detected by both fluorometry and visual spectrophotometry. Thus, the content of metal ions in the tested samples can be determined by measuring the level of urea generated after enzymatic hydrolysis of Arg by reconstructed arginase holoenzyme in the presence of tested metal ions. The linearity range of the fluorometric apo-arginase-DMO method in the case of Mn2+ assay is from 4pM to 1.10nM with a limit of detection of 1pM Mn2+, whereas the linearity range of the present method in the case of Co2+ assay is from 8pM to 45nM with a limit of detection of 2.5pM Co2+. The proposed method being highly sensitive, selective, valid and low-cost, may be useful to monitor Mn2+ and Co2+ content in clinical laboratories, food industry and environmental control service.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.031
      Issue No: Vol. 193 (2017)
       
  • A novel fluorescent probe (dtpa-bis(cytosine)) for detection of Eu(III) in
           rare earth metal ions
    • Authors: Fan Yang; Peipei Ren; Guanhong Liu; Youtao Song; Naishun Bu; Jun Wang
      Pages: 357 - 364
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Fan Yang, Peipei Ren, Guanhong Liu, Youtao Song, Naishun Bu, Jun Wang
      In this paper, a novel fluorescent probe, dtpa-bis(cytosine), was designed and synthesized for detecting europium (Eu3+) ion. Upon addition of Eu3+ ions into the dtpa-bis(cytosine) solution, the fluorescence intensity can strongly be enhanced. Conversely, adding other rare earth metal ions, such as Y3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Yb3+ and Lu3+, into dtpa-bis(cytosine) solution, the fluorescence intensity is decreased slightly. Some parameters affecting the fluorescence intensity of dtpa-bis(cytosine) solution in the presence of Eu3+ ions were investigated, including solution pH value, Eu3+ ion concentration and interfering substances. The detection mechanism of Eu3+ ion using dtpa-bis(cytosine) as fluorescent probe was proposed. Under optimum conditions, the fluorescence emission intensities of EuIII-dtpa-bis(cytosine) at 375nm in the concentration range of 0.50×10−5 mol∙L−1–5.00×10−5 mol∙L−1 of Eu3+ ion display a better linear relationship. The limit of detection (LOD) was determined as 8.65×10−7 mol∙L−1 and the corresponding correlation coefficient (R2) of the linear equation is 0.9807. It is wished that the proposed method could be applied for sensitively and selectively detecting Eu3+ ion.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.038
      Issue No: Vol. 193 (2017)
       
  • Innovative spectrophotometric methods for simultaneous estimation of the
           novel two-drug combination: Sacubitril/Valsartan through two manipulation
           approaches and a comparative statistical study
    • Authors: Maya S. Eissa; Amal M. Abou Al Alamein
      Pages: 365 - 374
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Maya S. Eissa, Amal M. Abou Al Alamein
      Different innovative spectrophotometric methods were introduced for the first time for simultaneous quantification of sacubitril/valsartan in their binary mixture and in their combined dosage form without prior separation through two manipulation approaches. These approaches were developed and based either on two wavelength selection in zero-order absorption spectra namely; dual wavelength method (DWL) at 226nm and 275nm for valsartan, induced dual wavelength method (IDW) at 226nm and 254nm for sacubitril and advanced absorbance subtraction (AAS) based on their iso-absorptive point at 246nm (λiso) and 261nm (sacubitril shows equal absorbance values at the two selected wavelengths) or on ratio spectra using their normalized spectra namely; ratio difference spectrophotometric method (RD) at 225nm and 264nm for both of them in their ratio spectra, first derivative of ratio spectra (DR1) at 232nm for valsartan and 239nm for sacubitril and mean centering of ratio spectra (MCR) at 260nm for both of them. Both sacubitril and valsartan showed linearity upon application of these methods in the range of 2.5–25.0μg/mL. The developed spectrophotmetric methods were successfully applied to the analysis of their combined tablet dosage form ENTRESTO™. The adopted spectrophotometric methods were also validated according to ICH guidelines. The results obtained from the proposed methods were statistically compared to a reported HPLC method using Student t-test, F-test and a comparative study was also developed with one-way ANOVA, showing no statistical difference in accordance to precision and accuracy.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.050
      Issue No: Vol. 193 (2017)
       
  • Insights on the interaction of Zn2+ cation with triazoles: Structures,
           bonding, electronic excitation and applications
    • Authors: R. Dahmani; S. Ben Yaghlane; S. Boughdiri; M. Mogren Al-Mogren; M. Prakash; M. Hochlaf
      Pages: 375 - 384
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): R. Dahmani, S. Ben Yaghlane, S. Boughdiri, M. Mogren Al-Mogren, M. Prakash, M. Hochlaf
      At present, we investigate the structures, the stability, the bonding and the spectroscopy of the Zn2+-triazole complexes (Zn2+-Tz), which are subunits of triazolate based porous materials and Zn-enzymes. This theoretical work is performed using ab initio methods and density functional theory (DFT) where dispersion correction is included. Through these benchmarks, we establish the ability and reliability of M05-2X+D3 and PBE0+D3 functionals for the correct description of Zn2+-Tz bond since these DFTs lead to close agreement with post Hartree-Fock methods. Therefore, M05-2X+D3 and PBE0+D3 functionals are recommended for the characterization of larger organometallic complexes formed by Zn and N-rich linkers. For Zn2+-Tz, we found two stable σ-type complexes: (i) a planar structure where Zn2+ links to unprotonated nitrogen and (ii) an out-of-plane cluster where carbon interacts with Zn2+. The most stable isomers consist on a coordinated covalent bond between the lone pair of unprotonated nitrogen and the vacant 4s orbital of Zn2+. The roles of covalent interactions within these complexes are discussed after vibrational, NBO, NPA charges and orbital analyses. The bonding is dominated by charge transfer from Zn2+ to Tz and intramolecular charge transfer, which plays a vital role for the catalytic activity of these complexes. These findings are important to understand, at the microscopic level, the structure and the bonding within triazolate based macromolecular porous materials and Zn-enzymes.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.017
      Issue No: Vol. 193 (2017)
       
  • Spectroscopic studies of ozone in cryosolutions: FT-IR spectra of 16O3 in
           liquid nitrogen, oxygen, argon and krypton
    • Authors: Kirill M. Bulanin; Michael O. Bulanin; Aida V. Rudakova; Tatiana D. Kolomijtsova; Dmitrij N. Shchepkin
      Pages: 385 - 392
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Kirill M. Bulanin, Michael O. Bulanin, Aida V. Rudakova, Tatiana D. Kolomijtsova, Dmitrij N. Shchepkin
      We have measured and interpreted the IR spectra of ozone dissolved in liquid nitrogen, oxygen, argon, and krypton in the 650–4700cm−1 spectral region at 79–117K. Frequency shifts, band intensities and bandshapes of 22 spectral features of soluted ozone were analyzed. The bands of the А 1 symmetry have a complex contour and possess an excess intensity with respect to the value of the purely vibrational transition moment. It was found that this effect is related to the manifestation of the Coriolis interaction. The bandshape distortion manifests itself as an additional intensity from the side of the В 1 symmetry band being an intensity source in the case of the Coriolis interaction.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.11.037
      Issue No: Vol. 193 (2017)
       
  • Plackett-Burman and Box-Behnken designs as chemometric tools for
           micro-determination of l-Ornithine
    • Authors: Marwa S. Elazazy; Marwa El-Hamshary; Marwa Sakr; Hala S. Al-Easa
      Pages: 397 - 406
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Marwa S. Elazazy, Marwa El-Hamshary, Marwa Sakr, Hala S. Al-Easa
      Plackett-Burman (PB) and Box-Behnken (BB) screening and response surface factorial designs were used to evaluate spectrophotometric and spectrofluorimetric approaches for the determination of l-Ornithine (ORN) as per se and in dietary supplements. Both approaches were based on the derivatization of the primary amino group of ORN via Hantzsch condensation reaction producing yellow coloured adducts (dihydrolutidine derivative). The reaction product was determined spectrophotometrically (method A) at λmax =327nm and spectrofluorimetrically (method B) at 480nm (λem) after excitation at 325nm (λex). A multivariate scheme was tailored to investigate the process numerical variables; reaction temperature, heating time, reagent volume, and pH implementing PB as a screening design followed by BB as an optimization strategy. Categorical factors including diluting solvent and sequence of addition were kept invariable. Responses of the reaction systems were the maximum absorbance (Y1) and maximum fluorescence intensity (Y2), correspondingly. Quality tools as well as ANOVA testing, before and after response transformation were used to decide upon the substantial variables. Following the optimization of reaction variables using desirability plots, calibration graphs were found to be rectilinear in the range of 6–14μg/mL and 0.4–1.2μg/mL for methods A and B, respectively. Both methods proved to be sensitive with detection limits (DL) of 337 and 85ng/mL, and quantitation limits (QL) of 1086 and 283ng/mL, for methods A and B, respectively. An interference study was performed using potential foreign species. No significant interference effect was observed on any of the proposed procedures. System performance was addressed following ICH guidelines and considering parameters such as linearity, detection and quantification limits, accuracy and precision, robustness and specificity.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.044
      Issue No: Vol. 193 (2017)
       
  • Photophysicochemical behaviour and antimicrobial properties of monocarboxy
           Mg (II) and Al (III) phthalocyanine-magnetite conjugates
    • Authors: Mopelola Abidemi Idowu; Solami Xego; Yasin Arslanoglu; John Mark; Edith Antunes; Tebello Nyokong
      Pages: 407 - 414
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Mopelola Abidemi Idowu, Solami Xego, Yasin Arslanoglu, John Mark, Edith Antunes, Tebello Nyokong
      Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine–AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs–AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.052
      Issue No: Vol. 193 (2017)
       
  • A highly selective and sensitive fluorescent chemosensor and its
           application for rapid on-site detection of Al3+
    • Authors: Xiao-li Yue; Zhao-qing Wang; Chao-rui Li; Zheng-yin Yang
      Pages: 415 - 421
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Xiao-li Yue, Zhao-qing Wang, Chao-rui Li, Zheng-yin Yang
      In this paper, a simple naphthalene-based derivative (HL) has been designed and synthesized as a Al3+-selective fluorescent chemosensor based on the PET mechanism. HL exhibited high selectivity and sensitivity towards Al3+ over other commonly coexisting metal ions in ethanol with a detection limit of 2.72nM. The 1:1 binding stoichiometry of the complex (HL-Al3+) was determined from the Job's plot based on fluorescence titrations and the ESI-MS spectrum data. Moreover, the binding site of HL with Al3+ was assured by the 1H NMR titration experiment. The binding constant (Ka) of the complex (HL-Al3+) was calculated to be 5.06×104 M−1 according to the Benesi-Hildebrand equation. In addition, the recognizing process of HL towards Al3+ was chemically reversible by adding Na2EDTA. Importantly, HL could directly and rapidly detect aluminum ion through the filter paper without resorting to additional instrumental analysis.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.053
      Issue No: Vol. 193 (2017)
       
  • Investigations on the spectroscopic properties of Dy3+ ions doped Zinc
           calcium tellurofluoroborate glasses
    • Authors: P. Karthikeyan; S. Arunkumar; K. Annapoorani; K. Marimuthu
      Pages: 422 - 431
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): P. Karthikeyan, S. Arunkumar, K. Annapoorani, K. Marimuthu
      A new series of Dy3+ doped (30–x)B2O3 +30TeO2 +20CaCO3 +10ZnO+10ZnF2 +xDy2O3 (x=0.01, 0.1, 0.5, 1, 2 and 3 in wt%) Zinc calcium tellurofluoroborate glasses were prepared and their structural, luminescence and excited state dynamics have been studied and reported. The structural properties have been characterized through XRD and FTIR studies to confirm the amorphous nature and to explore the presence of fundamental stretching vibrations. The bonding parameters (δ and β), optical band gap, Urbach's energy, oscillator strengths and Judd-Ofelt (JO) intensity parameters were calculated from the absorption spectra. The JO intensity parameters and the Y/B intensity ratio values have been used to explore the nature of the bonding and asymmetry around the Dy-ligand field environment. The luminescence properties of the present Dy3+ doped glasses have been analyzed through luminescence excited state dynamics and radiative properties such as transition probability (A), stimulated emission cross-section (σP E) branching ratio (β) and radiative lifetime (τR) values. The combination of dominant blue (4F9/2 → 6H15/2) and yellow (4F9/2 → 6H13/2) emissions generates white light emission in the CIE chromaticity diagram thus suggests that the present Dy3+ doped glasses are suitable for white light applications. The lifetime of the 4F9/2 excited state is found to decrease with the increase in Dy3+ ion content and the concentration quenching of the Dy3+ ions emission could be ascribed due to the resonant energy transfer and cross-relaxation processes. The non-exponential behavior of the decay curves has been analyzed with Inokuti-Hirayama model and the interaction between the Dy3+ ions is of electric dipole-dipole in nature.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.049
      Issue No: Vol. 193 (2017)
       
  • Analysis of 19th century ceramic fragments excavated from Pirenópolis
           (Goiás, Brazil) using FT-IR, Raman, XRF and SEM
    • Authors: Renato P. Freitas; Filipe A. Coelho; Valter S. Felix; Marcelo O. Pereira; Marcos André Torres de Souza; Marcelino J. Anjos
      Pages: 432 - 439
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Renato P. Freitas, Filipe A. Coelho, Valter S. Felix, Marcelo O. Pereira, Marcos André Torres de Souza, Marcelino J. Anjos
      This study used Raman, FT-IR and XRF spectroscopy and SEM to analyze ceramic fragments dating from the 19th century, excavated from an old farm in the municipality of Pirenópolis, Goiás, Brazil. The results show that the samples were produced in an open oven at a firing temperature below 500°C, using raw materials including kaolinite, hematite, magnetite, quartz, microcline, albite, anhydrite, calcite, illite, orthoclase and MnO2. Although the analyses showed similarities in the manufacturing process and the presence of many minerals was common in all samples, multivariate statistical methods (PCA) allowed a more detailed assessment of similarities and differences in the mineral composition of the samples. The results of the PCA showed that the samples excavated in one of the slave quarters (senzalas) group with those excavated at the farmhouse, where the landowner lived, which indicates a paternalistic attitude towards captives, including the sharing of ceramic materials of everyday use.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.047
      Issue No: Vol. 193 (2017)
       
  • Rotational study on the van der Waals complex
           1-chloro-1,1-difluoroethane-argon
    • Authors: Juan Wang; Junhua Chen; Gang Feng; Zhining Xia; Qian Gou
      Pages: 447 - 450
      Abstract: Publication date: 15 March 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 193
      Author(s): Juan Wang, Junhua Chen, Gang Feng, Zhining Xia, Qian Gou
      The rotational spectrum of the van der Waals complex formed between 1-chloro-1,1-difluoroethane and argon has been investigated by using a pulsed jet Fourier transform microwave spectrometer. Only one set of rotational transitions belonging to the lowest energy conformer has been observed and assigned, although theoretical calculations suggest six stable conformers that might be observed. The observed conformer, according to the experimental evidence from two isotopologues (35Cl and 37Cl), adopts a configuration in which the argon atom is located, close to the CF2Cl top, between the CCF and CCCl planes (the dihedral angle ∠ArCCCl is 65.2°). The distance between argon atom and the center of mass of CH3CF2Cl is 3.949(2) Å. The dissociation energy, with pseudo diatomic approximation, is evaluated to be 2.4kJmol−1.
      Graphical abstract image

      PubDate: 2017-12-27T02:50:12Z
      DOI: 10.1016/j.saa.2017.12.062
      Issue No: Vol. 193 (2017)
       
 
 
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