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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  [3051 journals]
  • Highly sensitive determination of diclofenac based on resin beads and a
           novel polyclonal antibody by using flow injection chemiluminescence
           competitive immunoassay
    • Authors: Jing Shi; Mingxia Xu; Qinghui Tang; Kang Zhao; Anping Deng; Jianguo Li
      Pages: 1 - 7
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Jing Shi, Mingxia Xu, Qinghui Tang, Kang Zhao, Anping Deng, Jianguo Li
      A novel flow injection chemiluminescence immunoassay for simple, sensitive and low-cost detection of diclofenac was established based on specific binding of antigen and antibody. Carboxylic resin beads used as solid phase carrier materials provided good biocompatibility and large surface-to-volume ratio for modifying more coating antigen. There was a competitive process between the diclofenac in solution and the immobilized coating antigen to react with the limited binding sites of the polyclonal antibody to form the immunocomplex. The second antibody labelled with horseradish peroxidase was introduced into the immunosensor and trapped by captured polyclonal antibody against diclofenac, which could effectively amplify chemiluminescence signals of luminol-PIP-H2O2. Under optimal conditions, the diclofenac could be detected quantitatively. The chemiluminescence intensity decreased linearly with the logarithm of the diclofenac concentration in the range of 0.1–100ngmL−1 with a detection limit of 0.05ngmL−1 at a signal-to-noise ratio of 3. The immunosensor exhibited high sensitivity, specificity and acceptable stability. This easy-operated and cost-effective analytical method could be valuable for the diclofenac determination in real water samples.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.09.068
      Issue No: Vol. 191 (2017)
       
  • An azine based sensor for selective detection of Cu2+ ions and its copper
           complex for sensing of phosphate ions in physiological conditions and in
           living cells
    • Authors: Karishma Tiwari; Sumit Kumar; Vipan Kumar; Jeevanjot Kaur; Saroj Arora; Rakesh Kumar Mahajan
      Pages: 16 - 26
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Karishma Tiwari, Sumit Kumar, Vipan Kumar, Jeevanjot Kaur, Saroj Arora, Rakesh Kumar Mahajan
      A simple and cost effective unsymmetrical azine based Schiff base, 5-diethylamino-2-[(2-hydroxy-benzylidene)hydrazonomethyl]-phenol (1) was synthesized which selectively detect Cu2+ ions in the presence of other competitive ions through “naked eye” in physiological conditions (EtOH–buffer (1:1, v/v, HEPES 10mM, pH=7.4)). The presence of Cu2+ induce color change from light yellow green to yellow with the appearance of a new band at 450nm in UV–Vis spectra of Schiff base 1. The fluorescence of Schiff base 1 (10μM) was quenched completely in the presence of 2.7 equiv. of Cu2+ ions. Sub-micromolar limit of detection (LOD=3.4×10−7 M), efficient Stern–Volmer quenching constant (KSV =1.8×105 Lmol−1) and strong binding constant (log Kb =5.92) has been determined with the help of fluorescence titration profile. Further, 1−Cu2+ complex was employed for the detection of phosphate ions (PO4 3−, HPO4 2− and H2PO4 −) at micromolar concentrations in EtOH–buffer of pH7.4 based on fluorescence recovery due to the binding of Cu2+ with phosphate ions. Solubility at low concentration in aqueous medium, longer excitation (406nm) and emission wavelength (537nm), and biocompatibility of Schiff base 1 formulates its use in live cell imaging.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.09.072
      Issue No: Vol. 191 (2017)
       
  • Modification of Ti6Al4V surface by diazonium compounds
    • Authors: Mariusz Sandomierski; Tomasz Buchwald; Beata Strzemiecka; Adam Voelkel
      Pages: 27 - 35
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Mariusz Sandomierski, Tomasz Buchwald, Beata Strzemiecka, Adam Voelkel
      Ti6Al4V alloy is the most commonly used in orthopedic industry as an endoprosthesis. Ti6Al4V exhibits good mechanical properties, except the abrasion resistance. Surface modification of Ti6Al4V in order to obtain organic layer, and then the attachment of the polymer, can allow for overcoming this problem. The aim of the work was the modification of Ti6Al4V surface by diazonium compounds: salt or cation generated in situ and examine the influence of the reducing agent - ascorbic acid, and the temperature of reaction on modification process. Moreover, the simulated body fluid was used for the assessment of the organic layer stability on Ti6Al4V surface. The evaluation of the modification was carried out using the following methods: Raman microspectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Higher temperature of modification by 4-hydroxymethylbenzenediazonium cation, provides the largest amount of organic layer on the Ti6Al4V alloy. In the case of the Ti6Al4V modified by Variamine Blue B salt, the amount of organic layer is not dependent on the reaction condition. Moreover, the ascorbic acid and the presence of TiO2 does not effect on the modification. The modified surface is completely coated with the organic layer which is stable in simulated body fluid.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.09.070
      Issue No: Vol. 191 (2017)
       
  • Intramolecular deactivation processes of electronically excited
           Lanthanide(III) complexes with organic acids of low molecular weight
    • Authors: Katja Burek; Sascha Eidner; Stefanie Kuke; Michael U. Kumke
      Pages: 36 - 49
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Katja Burek, Sascha Eidner, Stefanie Kuke, Michael U. Kumke
      The luminescence of Lanthanide(III) complexes with different model ligands was studied under direct as well as sensitized excitation conditions. The research was performed in the context of studies dealing with deep-underground storages for high-level nuclear waste. Here, Lanthanide(III) ions served as natural analogues for Actinide(III) ions and the low-molecular weight organic ligands are present in clay minerals and furthermore, they were employed as proxies for building blocks of humic substances, which are important complexing molecules in the natural environment, e.g., in the far field of a repository site. Time-resolved luminescence spectroscopy was applied for a detailed characterization of Eu(III), Tb(III), Sm(III) and Dy(III) complexes in aqueous solutions. Based on the observed luminescence the ligands were tentatively divided into two groups (A, B). The luminescence of Lanthanide(III) complexes of group A was mainly influenced by an energy transfer to OH-vibrations. Lanthanide(III) complexes of group B showed ligand-related luminescence quenching, which was further investigated. To gain more information on the underlying quenching processes of group A and B ligands, measurements at different temperatures (77K≤ T ≤353K) were performed and activation energies were determined based on an Arrhenius analysis. Moreover, the influence of the ionic strength between 0M≤ I ≤4M on the Lanthanide(III) luminescence was monitored for different complexes, in order to evaluate the influence of specific conditions encountered in host rocks foreseen as potential repository sites.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.09.012
      Issue No: Vol. 191 (2017)
       
  • On the interaction between fluoxetine and lipid membranes: Effect of the
           lipid composition
    • Authors: Vy T. Pham; Trinh Q. Nguyen; Uyen P.N. Dao; Trang T. Nguyen
      Pages: 50 - 61
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Vy T. Pham, Trinh Q. Nguyen, Uyen P.N. Dao, Trang T. Nguyen
      Molecular interaction between the antidepressant fluoxetine and lipid bilayers was investigated in order to provide insights into the drug's incorporation to lipid membranes. In particular, the effects of lipid's unsaturation degree and cholesterol content on the partitioning of fluoxetine into large unilamellar vesicles (LUVs) comprised of unsaturated 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were evaluated using second derivative spectrophotometry and Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). It was found that fluoxetine partitioned to a greater extent into the liquid-crystalline DOPC LUVs than into the solid-gel DPPC LUVs. The lipid physical state dependence of drug partitioning was verified by increasing the temperature in which the partition coefficient of fluoxetine significantly increased upon the change of the lipid phase from solid-gel to liquid-crystalline. The incorporation of 28mol% cholesterol into the LUVs exerted a significant influence on the drug partitioning into both DOPC and DPPC LUVs. The ATR-FTIR study revealed that fluoxetine perturbed the conformation of DOPC more strongly than that of DPPC due to the cis-double bonds in the lipid acyl chains. Fluoxetine possibly bound to the carbonyl moiety of the lipids through the hydrogen bonding formation while displaced some water molecules surrounding the PO2 − regions of the lipid head groups. Cholesterol, however, could lessen the interaction between fluoxetine and the carbonyl groups of both DOPC and DPPC LUVs. These findings provided a better understanding of the role of lipid structure and cholesterol on the interaction between fluoxetine and lipid membranes, shedding more light into the drug's therapeutic action.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.09.050
      Issue No: Vol. 191 (2017)
       
  • A new turn-on fluorimetric method for the rapid speciation of
           Cr(III)/Cr(VI) species in tea samples with rhodamine-based fluorescent
           reagent
    • Authors: Esra Özyol; Şerife Saçmacı; Mustafa Saçmacı; Ahmet Ülgen
      Pages: 62 - 68
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Esra Özyol, Şerife Saçmacı, Mustafa Saçmacı, Ahmet Ülgen
      A new fluorimetric method with rhodamine-based fluorescent agent was developed for the rapid speciation of Cr(III)/Cr(VI) in tea, soil and water samples. The system, which utilizes a fluorescent reagent, was used for the first time after synthesis/characterization of 3′,6′-bis(diethylamino)-2-{[(1E)-(2,4-dimethoxyphenyl)methylene] amino}spiro[isoindole-1,9′-xanthen]-3(2H)-one (BDAS). The reagent responds instantaneously at room temperature in a 1:1 stoichiometric manner to the amount of Cr(III). The selectivity of this system for Cr(III) over other metal ions is remarkably high, and its sensitivity is below 0.01mgL−1 in aqueous solutions which enables a simplification without any pretreatment of the real sample. The method has a wide linear range of 0.1–10mgL−1 and a detection limit of 0.15μgL−1 for Cr(III) while the relative standard deviation was 0.1% for 0.1mgL−1 Cr(III) concentration. The results of detection and recovery experiments for Cr(III) in tea, soil and water were satisfactory, indicating that the method has better feasibility and application potential in the routine determination and speciation of Cr(III)/Cr(VI). The results of analysis of the certified reference material (INCT-TL-1 tea sample and CWW-TM-D waste water) are in good agreement with the certified value.
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      PubDate: 2017-10-05T06:46:20Z
      DOI: 10.1016/j.saa.2017.10.005
      Issue No: Vol. 191 (2017)
       
  • Coumarin based colorimetric and fluorescence on-off chemosensor for F−,
           CN− and Cu2+ ions
    • Authors: Debashis Roy; Arijit Chakraborty; Rina Ghosh
      Pages: 69 - 78
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Debashis Roy, Arijit Chakraborty, Rina Ghosh
      (E)-4-Chloro-3-[{2-(4-nitrophenyl)hydrazono}methyl]-2H-chromen-2-one (C), a coumarin derivative has been studied toward its ion sensing properties for F−, CN− and Cu2+. A proton-transfer mechanism for F− sensing has been deduced with the help of 1H NMR titration alongwith from the changes in the absorption and emission spectra of C in the presence of F−. C formed 1:1 stoichiometric complex with each of these analytes. Sensing of C toward Cu2+ is poor, but interestingly in the presence of F− or CN− the sensing ability of Cu2+ gets enhanced many folds, and C can act as F− or CN− mediated off-on sensor for Cu2+. Moreover, colorimetric strip (pre-coated with the coumarin derived compound) tests for F− and CN− from their DMSO solution at high temperature (~100°C) opens up the door for easiest naked eye recognition and distinction of these ions, and also for naked-eye detection of F− and CN− from its aqueous solution at high temperature (~100°C).
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      PubDate: 2017-10-11T22:03:08Z
      DOI: 10.1016/j.saa.2017.09.071
      Issue No: Vol. 191 (2017)
       
  • Highly sensitive “turn-on” fluorescent chemical sensor for trace
           analysis of Cr3+ using electro-synthesized
           poly(N-(9-fluorenylmethoxycarbonyl)-l-histidine)
    • Authors: Hui Zhang; Ge Zhang; Jingkun Xu; Yangping Wen; Shouli Ming; Jie Zhang; Wanchuan Ding
      Pages: 79 - 87
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Hui Zhang, Ge Zhang, Jingkun Xu, Yangping Wen, Shouli Ming, Jie Zhang, Wanchuan Ding
      Trivalent chromium (Cr3+) can cause severely environment pollution, declining quality of edible agro-products in plants and animals, and human diseases. Poly(N-(9-fluorenylmethoxycarbonyl)-l-histidine) (PFLH) synthesized by the direct electro-polymerization of its corresponding commercially available monomer in both boron trifluoride diethyl etherate and dichloromethane mixed system. The “turn-on” type fluorescent sensor based on PFLH displayed high sensitivity and selectivity for Cr3+ detecting. The structure of PFLH was rationally proved by 1H NMR spectra, FT-IR spectra, quantum chemical calculations, and its optical properties were characterized. The electro-synthesized PFLH exhibited a “turn-on” fluorescent response towards Cr3+, which was employed as a sensing platform for the “turn-on” fluorescent analysis of Cr3+ in a wide linear range from 5.1nM to 25μM with a low limit of detection as low as 1.7nM. The possible mechanism of fluorescent “turn-on” sensor based on PFLH for Cr3+ was proposed. The sensor displayed high sensitivity, good selectivity, satisfactory practicability, suggesting that PFLH has potential fluorescent application for “turn-on” sensing Cr3+ in agricultural environments and edible agro-products of plants and animals.
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      PubDate: 2017-10-11T22:03:08Z
      DOI: 10.1016/j.saa.2017.09.008
      Issue No: Vol. 191 (2017)
       
  • Use of zero order diffraction of a grating monochromator towards
           convenient and sensitive detection of fluorescent analytes in multi
           fluorophoric systems
    • Authors: Suraj Kumar Panigrahi; Ashok Kumar Mishra
      Pages: 98 - 103
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Suraj Kumar Panigrahi, Ashok Kumar Mishra
      White light excitation fluorescence (WLEF) is known to possess analytical advantage in terms of enhanced sensitivity and facile capture of the entire fluorescence spectral signature of multi component fluorescence systems. Using the zero order diffraction of the grating monochromator on the excitation side of a commercial spectrofluorimeter, it has been shown that WLEF spectral measurements can be conveniently carried out. Taking analyte multi-fluorophoric systems like (i) drugs and vitamins spiked in urine sample, (ii) adulteration of extra virgin olive oil with olive pomace oil and (iii) mixture of fabric dyes, it was observed that there is a significant enhancement of measurement sensitivity. The total fluorescence spectral response could be conveniently analysed using PLS2 regression. This work brings out the ease of the use of a conventional fluorimeter for WLEF measurements.
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      PubDate: 2017-10-11T22:03:08Z
      DOI: 10.1016/j.saa.2017.10.004
      Issue No: Vol. 191 (2017)
       
  • Incorporation of surface plasmon resonance with novel valinomycin doped
           chitosan-graphene oxide thin film for sensing potassium ion
    • Authors: Afiq Azri Zainudin; Yap Wing Fen; Nor Azah Yusof; Sura Hmoud Al-Rekabi; Mohd Adzir Mahdi; Nur Alia Sheh Omar
      Pages: 111 - 115
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Afiq Azri Zainudin, Yap Wing Fen, Nor Azah Yusof, Sura Hmoud Al-Rekabi, Mohd Adzir Mahdi, Nur Alia Sheh Omar
      In this study, the combination of novel valinomycin doped chitosan-graphene oxide (C–GO–V) thin film and surface plasmon resonance (SPR) system for potassium ion (K+) detection has been developed. The novel C–GO–V thin film was deposited on the gold surface using spin coating technique. The system was used to monitor SPR signal for K+ in solution with and without C–GO–V thin film. The K+ can be detected by measuring the SPR signal when C–GO–V thin film is exposed to K+ in solution. The sensor produces a linear response for K+ ion up to 100ppm with sensitivity and detection limit of 0.00948°ppm−1 and 0.001ppm, respectively. These results indicate that the C–GO–V film is high potential as a sensor element for K+ that has been proved by the SPR measurement.
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      PubDate: 2017-10-11T22:03:08Z
      DOI: 10.1016/j.saa.2017.10.013
      Issue No: Vol. 191 (2017)
       
  • Unveiling the stimulatory effects of tartrazine on human and bovine serum
           albumin fibrillogenesis: Spectroscopic and microscopic study
    • Authors: Nasser Abdulatif Al-Shabib; Javed Masood Khan; Mohammad A. Alsenaidy; Abdulrahman M. Alsenaidy; Mohd Shahnawaz Khan; Fohad Mabood Husain; Mohammad Rashid Khan; Mohammad Naseem; Priyankar Sen; Parvez Alam; Rizwan Hasan Khan
      Pages: 116 - 124
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Nasser Abdulatif Al-Shabib, Javed Masood Khan, Mohammad A. Alsenaidy, Abdulrahman M. Alsenaidy, Mohd Shahnawaz Khan, Fohad Mabood Husain, Mohammad Rashid Khan, Mohammad Naseem, Priyankar Sen, Parvez Alam, Rizwan Hasan Khan
      Amyloid fibrils are playing key role in the pathogenesis of various neurodegenerative diseases. Generally anionic molecules are known to induce amyloid fibril in several proteins. In this work, we have studied the effect of anionic food additive dye i.e., tartrazine (TZ) on the amyloid fibril formation of human serum albumins (HSA) and bovine serum albumin (BSA) at pHs7.4 and 3.5. We have employed various biophysical methods like, turbidity measurements, Rayleigh Light Scattering (RLS), Dynamic Light Scattering (DLS), intrinsic fluorescence, Congo red assay, far-UV CD, transmission electron microscopy (TEM) and atomic force microscopy (AFM) to decipher the mechanism of TZ-induce amyloid fibril formation in both the serum albumins at pHs7.4 and 3.5. The obtained results suggest that both the albumins forms amyloid-like aggregates in the presence of 1.0 to 15.0mM of TZ at pH3.5, but no amyloid fibril were seen at pH7.4. The possible cause of TZ-induced amyloid fibril formation is electrostatic and hydrophobic interaction because sulfate group of TZ may have interacted electrostatically with positively charged amino acids of the albumins at pH3.5 and increased protein-protein and protein-TZ interactions leading to amyloid fibril formation. The TEM, RLS and DLS results are suggesting that BSA forms bigger size amyloids compared to HSA, may be due to high surface hydrophobicity of BSA.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.09.062
      Issue No: Vol. 191 (2017)
       
  • Research on differences between 2-(2′-pyridyl)benzimidazole and
           
    • Authors: Maojiang Song; Fei Yang; Liping Liu; Caixia Su
      Pages: 125 - 133
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Maojiang Song, Fei Yang, Liping Liu, Caixia Su
      Due to the important pharmaceutical activities of benzimidazole derivatives, the differences between 2-(2′-pyridyl)benzimidazole and 2-(4′-pyridyl)benzimidazole were researched by terahertz time-domain spectroscopy and density functional theory systematically. Although the only difference between their molecular configurations is the different arrangement of nitrogen on pyridine ring, 2PBI and 4PBI have large differences in their experimental absorption spectra in the range of 0.2–2.5THz, such as the amount, amplitude and frequency position of absorption peaks. The validity of these results was confirmed by the theoretical results simulated using density functional theory. The possible reasons of these differences originate from the different dihedral angles between benzimidazole ring and pyridine ring and the different hydrogen-bonding interactions within crystal cell.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.001
      Issue No: Vol. 191 (2017)
       
  • Characterization and cysteine sensing performance of nanocomposites based
           on up-conversion excitation host and rhodamine-derived probes
    • Authors: Zhao Yuqing; Xing Yi; Li Lihua; Ma Juanjuan
      Pages: 134 - 142
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Zhao Yuqing, Xing Yi, Li Lihua, Ma Juanjuan
      Optical sensing for cysteine (Cys) recognition is an interesting topic due to Cys biological participation. In this paper, two rhodamine-based chemosensors were designed for Cys optical sensing. For chemosensor photostability improvement, up-conversion nanocrystals were synthesized and used as excitation host. These nanocrystals were modified with a phase transfer reagent α-cyclodextrin (α-CD) to improve their compatibility with chemosensors. An efficient energy transfer from these nanocrystals to chemosensors under 980nm radiation was observed and confirmed by spectral match analysis, energy transfer radius calculation and emission decay lifetime comparison. A direct bonding mechanism between Cys and chemosensors with bonding stoichiometry of 1:1 was established by Job's plot experiment. Given the presence of Cys, chemosensor emission was increased, showing emission turn on effect. These two chemosensors showed good selectivity, improved photostability and linear sensing response towards Cys.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.009
      Issue No: Vol. 191 (2017)
       
  • Sodium deoxycholate mediated enhanced solubilization and stability of
           hydrophobic drug Clozapine in pluronic micelles
    • Authors: Pankaj Singla; Onkar Singh; Shruti Chabba; V.K. Aswal; Rakesh Kumar Mahajan
      Pages: 143 - 154
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Pankaj Singla, Onkar Singh, Shruti Chabba, V.K. Aswal, Rakesh Kumar Mahajan
      In this report, the solubilization behaviour of a hydrophobic drug Clozapine (CLZ) in micellar suspensions of pluronics having different hydrophilic lipophilic balance (HLB) ratios viz. P84, F127 and F108 in the absence and presence of bile salt sodium deoxycholate (SDC) has been studied. UV–Vis spectroscopy has been exploited to determine the solubilization capacity of the investigated micellar systems in terms of drug loading efficiency, average number of drug molecules solubilized per micelle (ns ), partition coefficient (P) and standard free energy of solubilization (∆ G °). The morphological and structural changes taking place in pluronics in different concentration regimes of SDC and with the addition of drug CLZ has been explored using dynamic light scattering (DLS) and small angle neutron scattering (SANS) measurements. The SANS results revealed that aggregation behaviour of pluronic-SDC mixed micelles gets improved in the presence of drug. The micropolarity measurements have been performed to shed light on the locus of solubilization of the drug in pure and mixed micellar systems. The compatibility between CLZ and drug carriers (pluronics and SDC) was confirmed using powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Among the investigated systems, P84-SDC mixed system was found to be highly efficient for CLZ loading. The long term stability data indicated that CLZ loaded P84-SDC mixed micellar formulation remained stable for 3months at room temperature. Further, it was revealed that the CLZ loaded P84-SDC mixed micelles are converted into CLZ loaded pure P84 micelles at 30-fold dilutions which remain stable up to 48-fold dilutions. The results from the present studies suggest that P84-SDC mixed micelles can serve as suitable delivery vehicles for hydrophobic drug CLZ.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.015
      Issue No: Vol. 191 (2017)
       
  • Hydrogen bond docking preference in furans: OH⋯π vs. OH⋯O
    • Authors: Xiaotong Jiang; Narcisse T. Tsona; Shanshan Tang; Lin Du
      Pages: 155 - 164
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Xiaotong Jiang, Narcisse T. Tsona, Shanshan Tang, Lin Du
      The docking sites of hydrogen bonds in complexes formed between 2,2,2-trifluoroethanol (TFE), furan (Fu), and 2-methyl furan (MF) have been investigated. Using density functional theory (DFT) calculations, gas phase and matrix isolation FTIR spectroscopies, the strengths of OH⋯O and OH⋯π hydrogen bonds in the complexes were compared to find the docking preference. Calculations suggest that the hydrogen bond donor, TFE, is more likely to dock onto the oxygen atom of the aromatic furans ring, and consequently, the OH⋯O type hydrogen bond is relatively stronger than the OH⋯π type. The FTIR spectrum in the OH-stretching fundamental range obtained at room temperatures has been compared with that obtained at extremely low temperatures in the matrix. The fundamental and the red shifts of OH-stretching vibrations were observed in both FTIR spectra, confirming the formation of hydrogen bonded complexes. By assessing the ability of furan and MF to participate in the formation of OH⋯O hydrogen bond, the effect of ring methylation has been highlighted. From the calculated geometric and thermodynamic parameters as well as the frequency shift of the OH-stretching vibrations in complexes, TFE–MF is found to be more stable than TFE–Fu, which suggests that the strength of the OH⋯O hydrogen bond in TFE–MF originates from the high activity of the furan molecule caused by the methylation of the aromatic ring. The present study furthers the knowledge of docking preference in heteroaromatic molecules and is helpful to understand the nature of intermolecular interactions between hydrogen bond donors and acceptors, including both electron-deficient atoms and π cloud.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.006
      Issue No: Vol. 191 (2017)
       
  • Electric field standing wave effects in internal reflection and ATR
           spectroscopy
    • Authors: Thomas G. Mayerhöfer; Jürgen Popp
      Pages: 165 - 171
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Thomas G. Mayerhöfer, Jürgen Popp
      We investigate electric field standing wave effects in the system semiinfinite incidence medium with high index of refraction/layer/vacuum, the latter being the semiinfinite exit medium. If the layer has a lower index of refraction than the incidence medium, then very strong resonances occur between the two critical angles of the system defined by the systems incidence medium/layer and incidence medium/vacuum, as the layer is then a cavity. In particular close to the lower critical angles, the evanescent fields extend strongly into the exit medium. Based on this effect we suggest two new spectroscopic modalities, namely interference-enhanced internal reflection Raman spectroscopy and interference-enhanced attenuated total reflection infrared spectroscopy.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.007
      Issue No: Vol. 191 (2017)
       
  • A relay identification fluorescence probe for Fe3+ and phosphate anion and
           its applications
    • Authors: Xu Tang; Yun Wang; Juan Han; Liang Ni; Lei Wang; Longhua Li; Huiqin Zhang; Cheng Li; Jing Li; Haoran Li
      Pages: 172 - 179
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Xu Tang, Yun Wang, Juan Han, Liang Ni, Lei Wang, Longhua Li, Huiqin Zhang, Cheng Li, Jing Li, Haoran Li
      A simple relay identification fluorescence probe for Fe3+ and phosphate anion with “on-off-on” switching was designed and synthesized based on the phenylthiazole and biphenylcarbonitrile. Probe 1 displayed highly selective and sensitive recognition to Fe3+ in HEPES aqueous buffer (EtOH/H2O=2:8, v/v, pH=7.4) solutions. The optimized structures and HOMO and LUMO of probe 1 and [1-Fe3+] complex were obtained by the density functional theory (DFT) calculations with B3LYP as the exchange and correlation functional using a suite of Gaussian 09 programs. The [1-Fe3+] complex solution also showed a high selectivity toward PO4 3−. The lower limits of detection of probe 1 to Fe3+ and [1-Fe3+] complex to PO4 3− were estimated to 1.09×10−7 M and 1.86×10−7 M. Besides, the probe 1 also was used to detected the target ions in real water sample and living cells successfully.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.018
      Issue No: Vol. 191 (2017)
       
  • A light-up probe targeting for Bcl-2 2345 G-quadruplex DNA with carbazole
           TO
    • Authors: Yingchun Gu; Dayong Lin; Yalin Tang; Xuening Fei; Cuihong Wang; Baolian Zhang; Jianguo Zhou
      Pages: 180 - 188
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Yingchun Gu, Dayong Lin, Yalin Tang, Xuening Fei, Cuihong Wang, Baolian Zhang, Jianguo Zhou
      As its significant role, the selective recognition of G-quadruplex with specific structures and functions is important in biological and medicinal chemistry. Carbazole derivatives have been reported as a kind of fluorescent probe with many excellent optical properties. In the present study, the fluorescence of the dye (carbazole TO) increased almost 70 fold in the presence of bcl-2 2345 G4 compared to that alone in aqueous buffer condition with almost no fluorescence and 10–30 fold than those in the presence of other DNAs. The binding study results by activity inhibition of G4/Hemin peroxidase experiment, NMR titration and molecular docking simulation showed the high affinity and selectivity to bcl-2 2345 G4 arises from its end-stacking interaction with G-quartet. It is said that a facile approach with excellent sensitive, good selectivity and quick response for bcl-2 2345 G-quadruplex was developed and may be used for antitumor recognition or antitumor agents.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.012
      Issue No: Vol. 191 (2017)
       
  • Highly selective and sensitive colorimetric determination of Cr3+ ion by
           4-amino-5-methyl-4H-1,2,4-triazole-3-thiol functionalized Au nanoparticles
           
    • Authors: Shima Shahrivari; Farnoush Faridbod; Mohammad Reza Ganjali
      Pages: 189 - 194
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Shima Shahrivari, Farnoush Faridbod, Mohammad Reza Ganjali
      In this work, a rapid, selective naked eyes colorimetric chemical probe for the detection of Cr3+ was developed based on functionalization of gold nanoparticles. For this purpose, surface of Au NPs was functionalized using 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol (AMTT). Through colorimetric studies, it was found that in the presence of Cr3+ ions, AMTT-Au NPs instantly aggregated and resulted in a color change of the solution from red to blue. The color change of AMTT-Au NPs due to the aggregation induced by Cr3+ can be seen with even naked eyes and also by UV–Vis spectroscopy with a detection limit of 1.8μM and 0.1μM, respectively. AMTT-Au NPs showed excellent selectivity toward Cr3+ compared to other cations tested, including K+, Na+, Cs+, Fe3+, Ni2+, Cu2+, Co2+, Zn2+, Ba2+, Ca2+, Mg2+, Cd2+, Pb2+, Hg2+ ions and especially all trivalent lanthanide ions. The absorbance ratio (A650/A525) was linear toward Cr3+ concentrations in the range of 0.6–6.1μM (R2 =0.996). The best response was achieved over a pH range of 3–5. Furthermore, the proposed colorimetric method based on AMTT-Au NPs was successfully used for Cr3+ ion detection in plasma sample and some water samples.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.09.064
      Issue No: Vol. 191 (2017)
       
  • Simultaneous determination of α-asarone and β-asarone in Acorus
           tatarinowii using excitation-emission matrix fluorescence coupled with
           chemometrics methods
    • Authors: Xue-Mei Bai; Tie Liu; De-Long Liu; Yong-Ju Wei
      Pages: 195 - 202
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Xue-Mei Bai, Tie Liu, De-Long Liu, Yong-Ju Wei
      A chemometrics-assisted excitation-emission matrix (EEM) fluorescence method was proposed for simultaneous determination of α-asarone and β-asarone in Acorus tatarinowii. Using the strategy of combining EEM data with chemometrics methods, the simultaneous determination of α-asarone and β-asarone in the complex Traditional Chinese medicine system was achieved successfully, even in the presence of unexpected interferents. The physical or chemical separation step was avoided due to the use of “mathematical separation”. Six second-order calibration methods were used including parallel factor analysis (PARAFAC), alternating trilinear decomposition (ATLD), alternating penalty trilinear decomposition (APTLD), self-weighted alternating trilinear decomposition (SWATLD), the unfolded partial least-squares (U-PLS) and multidimensional partial least-squares (N-PLS) with residual bilinearization (RBL). In addition, HPLC method was developed to further validate the presented strategy. Consequently, for the validation samples, the analytical results obtained by six second-order calibration methods were almost accurate. But for the Acorus tatarinowii samples, the results indicated a slightly better predictive ability of N-PLS/RBL procedure over other methods.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.011
      Issue No: Vol. 191 (2017)
       
  • Characterization of titanyl phthalocyanine (TiOPc) thin films by
           microscopic and spectroscopic method
    • Authors: R. Skonieczny; J. Makowiecki; B. Bursa; A. Krzykowski; M. Szybowicz
      Pages: 203 - 210
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): R. Skonieczny, J. Makowiecki, B. Bursa, A. Krzykowski, M. Szybowicz
      The titanyl phthalocyanine (TiOPc) thin film deposited on glass, silicon and gold substrate have been studied using Raman spectroscopy, atomic force microscopy (AFM), absorption and profilometry measurements. The TiOPc thin layers have been deposited at room temperature by the quasi-molecular beam evaporation technique. The Raman spectra have been recorded using micro Raman system equipped with a confocal microscope. Using surface Raman mapping techni que with polarized Raman spectra the polymorphic forms of the TiOPc thin films distribution have been obtained. The AFM height and phase image were examined in order to find surface features and morphology of the thin films. Additionally to compare experimental results, structure optimization and vibrational spectra calculation of single TiOPc molecule were performed using DFT calculations. The received results showed that the parameters like polymorphic form, grain size, roughness of the surface in TiOPc thin films can well characterize the obtained organic thin films structures in terms of their use in optoelectronics and photovoltaics devices.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.034
      Issue No: Vol. 191 (2017)
       
  • Investigation of the composition-structure-property relationship of
           AsxTe100−x films prepared by plasma deposition
    • Authors: Leonid Mochalov; Dominik Dorosz; Aleksey Nezhdanov; Mikhail Kudryashov; Sergey Zelentsov; Dmitry Usanov; Alexandr Logunov; Aleksandr Mashin; Daniela Gogova
      Pages: 211 - 216
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Leonid Mochalov, Dominik Dorosz, Aleksey Nezhdanov, Mikhail Kudryashov, Sergey Zelentsov, Dmitry Usanov, Alexandr Logunov, Aleksandr Mashin, Daniela Gogova
      AsxTe100−x amorphous films of different chemical content were prepared by Plasma-Enhanced Chemical Vapor Deposition (PECVD). For the first time the optical properties of As-Te chalcogenide materials have been measured in UV-VIS-IR ranges (from 0.2 to 25μm) for a very wide range of chemical compositions (20–80at.% As). As-Te films have been tuned from 0.80 to 1.10eV. The IR results obtained have been juxtaposed with the Raman spectroscopy findings to establish the correlation between optical and structural properties of the materials developed. Reversible and irreversible changes in the phase composition of the As-Te films under annealing of the surface by laser irradiation have been demonstrated and studied. In order to determine the potential areas of application of the prepared As-Te films the thermal and photo sensitivity has been also investigated.
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      PubDate: 2017-10-14T13:03:09Z
      DOI: 10.1016/j.saa.2017.10.038
      Issue No: Vol. 191 (2017)
       
  • A rapid, naked-eye detection of hypochlorite and bisulfite using a robust
           and highly-photostable indicator dye Quinaldine Red in aqueous medium
    • Authors: Tanoy Dutta; Falguni Chandra; Apurba L. Koner
      Pages: 217 - 220
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Tanoy Dutta, Falguni Chandra, Apurba L. Koner
      A “naked-eye” detection of health hazardous bisulfite (HSO3 −) and hypochlorite (ClO−) using an indicator dye (Quinaldine Red, QR) in a wide range of pH is demonstrated. The molecule contains a quinoline moiety linked to an N,N-dimethylaniline moiety with a conjugated double bond. Treatment of QR with HSO3 − and ClO−, in aqueous solution at near-neutral pH, resulted in a colorless product with high selectivity and sensitivity. The detection limit was 47.8μM and 0.2μM for HSO3 − and ClO− respectively. However, ClO− was 50 times more sensitive and with 2 times faster response compared to HSO3 −. The detail characterization and related analysis demonstrate the potential of QR for a rapid, robust and highly efficient colorimetric sensor for the practical applications to detect hypochlorite in water samples.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.037
      Issue No: Vol. 191 (2017)
       
  • Combination of hollow fluorescent carbon and gold nanoparticles: A
           super-catalyst
    • Authors: Kakali Santra; Pradipta Purkayastha
      Pages: 221 - 225
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Kakali Santra, Pradipta Purkayastha
      Hollow fluorescent carbon nanoparticles (HFCNs) have been combined with gold nanoparticles (AuNPs) to produce a special catalyst. The catalytic properties of HFCNs and AuNPs were exploited to conceptualize the new catalytic functionality. The AuNP-embedded-HFCNs produced in situ were found to massively enhance the rate of reduction of 4-nitrophenol (a model reaction) in presence of sodium borohydride. Comparison with functioning of other nanoparticulate catalysts on the same reaction proved our product to be an extremely efficient catalyst.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.028
      Issue No: Vol. 191 (2017)
       
  • Calorimetric and spectroscopic studies of the interaction between
           zidovudine and human serum albumin
    • Authors: Adrian Pîrnău; Mihaela Mic; Silvia Neamţu; Călin G. Floare; Mircea Bogdan
      Pages: 226 - 232
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Adrian Pîrnău, Mihaela Mic, Silvia Neamţu, Călin G. Floare, Mircea Bogdan
      A quantitative analysis of the interaction between zidovudine (AZT) and human serum albumin (HSA) was achieved using Isothermal titration calorimetry (ITC) in combination with fluorescence and 1H NMR spectroscopy. ITC directly measure the heat during a biomolecular binding event and gave us thermodynamic parameters and the characteristic association constant. By fluorescence quenching, the binding parameters of AZT-HSA interaction was determined and location to binding site I of HSA was confirmed. Via T1 NMR selective relaxation time measurements the drug-protein binding extent was evaluated as dissociation constants Kd and the involvement of azido moiety of zidovudine in molecular complex formation was put in evidence. All three methods indicated a very weak binding interaction. The association constant determined by ITC (3.58×102 M−1) is supported by fluorescence quenching data (2.74×102 M−1). The thermodynamic signature indicates that at least hydrophobic and electrostatic type interactions played a main role in the binding process.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.032
      Issue No: Vol. 191 (2017)
       
  • Determination of geographical origin and icariin content of Herba Epimedii
           using near infrared spectroscopy and chemometrics
    • Authors: Yue Yang; Yongjiang Wu; Weili Li; Xuesong Liu; Jiyu Zheng; Wentao Zhang; Yong Chen
      Pages: 233 - 240
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Yue Yang, Yongjiang Wu, Weili Li, Xuesong Liu, Jiyu Zheng, Wentao Zhang, Yong Chen
      Near infrared (NIR) spectroscopy coupled with chemometrics was used to discriminate the geographical origin of Herba Epimedii in this work. Four different classification models, namely discriminant analysis (DA), back propagation neural network (BPNN), K-nearest neighbor (KNN), and support vector machine (SVM), were constructed, and their performances in terms of recognition accuracy were compared. The results indicated that the SVM model was superior over the other models in the geographical origin identification of Herba Epimedii. The recognition rates of the optimum SVM model were up to 100% for the calibration set and 94.44% for the prediction set, respectively. In addition, the feasibility of NIR spectroscopy with the CARS-PLSR calibration model in prediction of icariin content of Herba Epimedii was also investigated. The determination coefficient (RP 2) and root-mean-square error (RMSEP) for prediction set were 0.9269 and 0.0480, respectively. It can be concluded that the NIR spectroscopy technique in combination with chemometrics has great potential in determination of geographical origin and icariin content of Herba Epimedii. This study can provide a valuable reference for rapid quality control of food products.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.019
      Issue No: Vol. 191 (2017)
       
  • DFT computations on: Crystal structure, vibrational studies and optical
           investigations of a luminescent self-assembled material
    • Authors: A. Kessentini; A. Ben Ahmed; T. Dammak; M. Belhouchet
      Pages: 241 - 248
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): A. Kessentini, A. Ben Ahmed, T. Dammak, M. Belhouchet
      The current work undertakes the growth and the physicochemical properties of a novel green-yellow luminescence semi-organic material, the 3-picolylammonium bromide abbreviated (Pico-Br). In this paper, we report the X-ray diffraction measurements which show that the crystal lattice consists of distinct 3-picolylammonium cations and free bromide anions connected via NH⋯Br and NH⋯N hydrogen bonds leading to form a two dimensional frameworks. Molecular geometry compared with its optimized counterpart shows that the quantum chemical calculations carried out with density functional method (DFT) well produce the perceived structure by X-ray resolution of the studied material. To provide further insight into the spectroscopic properties, additional characterization of this material have been performed with Raman and infrared studies at room temperature. Theoretical computations have been computed using the (DFT) method at B3LYP/LanL2DZ level of theory implemented within Gaussian 03 program to study the vibrational spectra of the investigated molecule in the ground state. Optical absorption spectrum inspected by UV–visible absorption reveals the appearance of sharp optical gap of 280nm (4.42eV) as well as a strong green photoluminescence emission at 550nm (2.25eV) is detected on the photoluminescence (PL) spectrum at room temperature. Using the TD/DFT method, HOMO–LUMO energy gap and the Mulliken atomic charges were calculated in order to get an insight into the material. Good agreement between the theoretical results and the experimental ones was predicted.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.035
      Issue No: Vol. 191 (2017)
       
  • A combined experimental (IR, Raman and UV–Vis) and quantum chemical
           study of canadine
    • Authors: Bhawani Datt Joshi; Anubha Srivastava; Poonam Tandon; Sudha Jain; A.P. Ayala
      Pages: 249 - 258
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Bhawani Datt Joshi, Anubha Srivastava, Poonam Tandon, Sudha Jain, A.P. Ayala
      Plant based natural products cover a major sector of the medicinal field, as such focus on plant research has been increased all over the world. As an attempt to aid that research, we have performed structural and spectroscopic analysis of a natural product, an alkaloid: canadine. Both ab initio Hartree-Fock (HF) and density functional theory (DFT) employing B3LYP using 6-311++G(d,p) basis set were used for the calculations. The calculated vibrational frequencies were scaled and compared with the experimental infrared and Raman spectra. The complete vibrational assignments were made using potential energy distribution. The structure-activity relation has also been interpreted by mapping electrostatic potential surface and evaluating the reactivity descriptors, which are valuable information for quality control of medicines and drug-receptor interactions. Natural bond orbital analysis has also been performed to understand the stability and hyperconjugative interactions of the molecule. Furthermore, UV–Vis spectra have been recorded in an ethanol solvent (EtOH) and the electronic property has been analyzed employing TD-DFT for both gaseous and solvent phase. The HOMO and LUMO calculation with their energy gap show that charge transfer occurs within the molecule. Additionally, the nonlinear optical properties of the title compound have been interpreted that predicts it's the best candidate for the NLO materials.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.008
      Issue No: Vol. 191 (2017)
       
  • Deciphering the complexation process of a fluoroquinolone antibiotic,
           levofloxacin, with bovine serum albumin in the presence of additives
    • Authors: Amandeep Kaur; Imran Ahmd Khan; Parampaul Kaur Banipal; Tarlok Singh Banipal
      Pages: 259 - 270
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Amandeep Kaur, Imran Ahmd Khan, Parampaul Kaur Banipal, Tarlok Singh Banipal
      The current work aims to explore the thermodynamic and conformational aspects for the binding of fluoroquinolone antibacterial drug, levofloxacin (LFC), with bovine serum albumin (BSA) using calorimetric, spectroscopic (UV–visible, fluorescence, circular dichroism, and 1H NMR), dynamic light scattering (DLS) and computational methods (molecular docking). The binding of LFC with BSA at two sequential sites with higher affinity (~103 M−1) at the first site has been explored by calorimetry whereas the binding at a single site with affinity of the order of ~104 M−1 has been observed from fluorescence spectroscopy. The calorimetric study in the presence of additives along with docking analysis reveals the significant role of electrostatic, hydrogen bonding, and hydrophobic interactions in the association process. The slight conformational changes in protein as well as the changes in the water network structure around the binding cavity of protein have been observed from spectroscopic and DLS measurements. The LFC induced quenching of BSA fluorescence was observed to be initiated mainly through the static quenching process and this suggests the formation of ground state LFC-BSA association complex. The stronger interactions of LFC in the cavity of Sudlow site I (subdomain IIA) of protein have been explored from site marker calorimetric and molecular docking study.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.017
      Issue No: Vol. 191 (2017)
       
  • Label-free aptamer-based sensor for specific detection of malathion
           residues by surface-enhanced Raman scattering
    • Authors: Yonghui Nie; Yuanjie Teng; Pan Li; Wenhan Liu; Qianwei Shi; Yuchao Zhang
      Pages: 271 - 276
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Yonghui Nie, Yuanjie Teng, Pan Li, Wenhan Liu, Qianwei Shi, Yuchao Zhang
      A novel label-free aptamer surface-enhanced Raman scattering (SERS) sensor for trace malathion residue detection was proposed. In this process, the binding of malathion molecule with aptamer is identified directly. The silver nanoparticles modified with positively charged spermine served as enhancing and capture reagents for the negatively charged aptamer. Then, the silver nanoparticles modified by aptamer were used to specifically capture the malathion. The SERS background spectra of spermine, aptamer, and malathion were recorded and distinguished with the spectrum of malathion–aptamer. To enhance the characteristic peak signal of malathion captured by the aptamer, the aggregate reagents (NaCl, KCl, MgCl2) were compared and selected. The selectivity of this method was verified in the mixed-pesticide standard solution, which included malathion, phosmet, chlorpyrifos-methyl, and fethion. Results show that malathion can be specifically identified when the mixed-pesticide interferences existed. The standard curve was established, presenting a good linear range of 5×10−7 to 1×10−5 mol·L−1. The spiked experiments for tap water show good recoveries from 87.4% to 110.5% with a relative standard deviation of less than 4.22%. Therefore, the proposed label-free aptamer SERS sensor is convenient, specifically detects trace malathion residues, and can be applied for qualitative and quantitative analysis of other pesticides.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.030
      Issue No: Vol. 191 (2017)
       
  • Photolysis study of octyl p-methoxycinnamate loaded microemulsion by
           molecular fluorescence and chemometric approach
    • Authors: Danielle Silva Nascimento; Matías Insausti; Beatriz Susana Fernández Band; Marcos Grünhut
      Pages: 277 - 282
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Danielle Silva Nascimento, Matías Insausti, Beatriz Susana Fernández Band, Marcos Grünhut
      Octyl p-methoxycinnamate (OMC) is one of the most widely used sunscreen agents. However, the efficiency of OMC as UV filter over time is affected due to the formation of the cis-isomer which presents a markedly lower extinction coefficient (εcis =12,600L mol−1 cm−1 at 291nm) than the original trans-isomer (εtrans =24,000L mol−1 cm−1 at 310nm). In this work, a novel carrier for OMC based on an oil-in-water microemulsion is proposed in order to improve the photostability of this sunscreen. The formulation was composed of 29.2% (w/w) of a 3:1 mixture of ethanol (co-surfactant) and decaethylene glycol mono-dodecyl ether (surfactant), 1.5% (w/w) of oleic acid (oil phase) and 69.2% (w/w) of water. This microemulsion was prepared in a simple way, under moderate stirring at 25°C and using acceptable, biocompatible and accessible materials for topical use. OMC was incorporated in the vehicle at a final concentration of 5.0% (w/w), taking into account the maximum permitted levels established by international norms. Then, a photolysis study of the loaded formulation was performed using a continuous flow system. The direct photolysis was monitored over time by molecular fluorescence. The recorded spectra data between 370 y 490nm were analyzed by multivariate curve resolution-alternating least squares algorithm. The kinetic rate constants corresponding to the photolysis of the trans-OMC were calculated from the concentration profiles, resulting in 0.0049s−1 for the trans-OMC loaded microemulsion and 0.0131s−1 for the trans-OMC in aqueous media. These results demonstrate a higher photostability of the trans-OMC when loaded in the proposed vehicle with respect to the free trans-OMC in aqueous media.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.025
      Issue No: Vol. 191 (2017)
       
  • The electric field standing wave effect in infrared transflection
           spectroscopy
    • Authors: Thomas G. Mayerhöfer; Jürgen Popp
      Pages: 283 - 289
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Thomas G. Mayerhöfer, Jürgen Popp
      We show that an electric field standing wave effect is responsible for the oscillations and the non-linear dependence of the absorbance on the layer thickness in thin layers on a reflective surface. This effect is connected to the occurrence of interference inside these layers. Consequently, the absorptance undergoes a maximum electric field intensity enhancement at spectral positions close to those where corresponding non-absorbing layers on a metal show minima in the reflectance. The effect leads to changes of peak maxima ratios with layer thickness and shows the same periodicity as oscillations in the peak positions. These peculiarities are fully based on and described by Maxwell's equations but cannot be understood and described if the strongly simplifying model centered on reflectance absorbance is employed.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.033
      Issue No: Vol. 191 (2017)
       
  • A novel surface plasmon resonance biosensor based on the PDA-AgNPs-PDA-Au
           film sensing platform for horse IgG detection
    • Authors: Ning Wang; Di Zhang; Xinyu Deng; Ying Sun; Xinghua Wang; Pinyi Ma; Daqian Song
      Pages: 290 - 295
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Ning Wang, Di Zhang, Xinyu Deng, Ying Sun, Xinghua Wang, Pinyi Ma, Daqian Song
      Herein we report a novel polydopamine-silver nanoparticle-polydopamine-gold (PDA-AgNPs-PDA-Au) film based surface plasmon resonance (SPR) biosensor for horse IgG detection. The PDA-AgNPs-PDA-Au film sensing platform was built on Au-film via layer-by-layer self-assembly. Ag ion was reduced in situ to AgNPs in presence of PDA. The top PDA layer can prevent AgNPs from being oxidized and connect with antibody via Schiff alkali reaction directly. The morphology and thickness of the modified gold film were characterized using scanning electron microscope and Talystep. Experimental results show that the PDA-AgNPs-PDA-Au film sensing platform is stable, regenerative and sensitive for horse IgG detection. The detection limit of horse IgG obtained with the present biosensor is 0.625μgmL−1, which is 2-fold and 4-fold lower than that obtained with biosensor based on PDA modified Au film and conventional biosensor based on MPA, respectively. Furthermore, when challenged to real serum samples, our sensor exhibited excellent specificity to horse IgG, suggesting its potential for industrial application.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.039
      Issue No: Vol. 191 (2017)
       
  • Quantitative determination of additive Chlorantraniliprole in Abamectin
           preparation: Investigation of bootstrapping soft shrinkage approach by
           mid-infrared spectroscopy
    • Authors: Hong Yan; Xiangzhong Song; Kuangda Tian; Yilin Chen; Yanmei Xiong; Shungeng Min
      Pages: 296 - 302
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Hong Yan, Xiangzhong Song, Kuangda Tian, Yilin Chen, Yanmei Xiong, Shungeng Min
      A novel method, mid-infrared (MIR) spectroscopy, which enables the determination of Chlorantraniliprole in Abamectin within minutes, is proposed. We further evaluate the prediction ability of four wavelength selection methods, including bootstrapping soft shrinkage approach (BOSS), Monte Carlo uninformative variable elimination (MCUVE), genetic algorithm partial least squares (GA-PLS) and competitive adaptive reweighted sampling (CARS) respectively. The results showed that BOSS method obtained the lowest root mean squared error of cross validation (RMSECV) (0.0245) and root mean squared error of prediction (RMSEP) (0.0271), as well as the highest coefficient of determination of cross-validation (Qcv 2) (0.9998) and the coefficient of determination of test set (Q2 test) (0.9989), which demonstrated that the mid infrared spectroscopy can be used to detect Chlorantraniliprole in Abamectin conveniently. Meanwhile, a suitable wavelength selection method (BOSS) is essential to conducting a component spectral analysis.
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      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.08.067
      Issue No: Vol. 191 (2017)
       
  • Relationship between protein molecular structural makeup and metabolizable
           
    • Authors: Saman Abeysekara; Nazir A. Khan; Peiqiang Yu
      Pages: 303 - 314
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Saman Abeysekara, Nazir A. Khan, Peiqiang Yu
      Protein solubility, ruminal degradation and intestinal digestibility are strongly related to their inherent molecular makeup. This study was designed to quantitatively evaluate protein digestion in the rumen and intestine of dairy cattle, and estimate the content of truly metabolizable protein (MP) in newly developed cool-season forage corn cultivars. The second objective was to quantify protein inherent molecular structural characteristics using advance molecular spectroscopic technique (FT/IR-ATR) and correlate it to protein metabolic characteristics. Six new cool-season corn cultivars, including 3 Pioneer (PNR) and 3 Hyland (HL), coded as PNR-7443R, PNR-P7213R, PNR-7535R, HL-SR06, HL-SR22, HL-BAXXOS-RR, were evaluated in the present study. The metabolic characteristics, MP supply to dairy cattle, and energy synchronization properties were modeled by two protein evaluation models, namely, the Dutch DVE/OEB system and the NRC-2001 model. Both models estimated significant (P<0.05) differences in contents of microbial protein (MCP) synthesis and truly absorbable rumen undegraded protein (ARUP) among the cultivars. The NRC-2001 model estimated significant (P<0.05) differences in MP content and degraded protein balance (DPB) among the cultivars. The contents MCP, ARUP and MP were higher (P<0.05) for cultivar HL-SR06, resulting in the lowest (P<0.05) DPB. However, none of the cultivars reached the optimal target hourly effective degradability ratio [25gNg/kg organic matter (OM)], demonstrating N deficiency in the rumen. There were non-significant differences among the cultivars in molecular-spectral intensities of protein. The amide I/II ratio had a significant correlation with ARUP (r =−0.469; P<0.001) and absorbable endogenous protein (AECPNRC) (P<0.001; r =0.612). Similarly, amide-II area had a weak but significant correlation (r =0.299; P<0.001) with RUP and ARUP, and with AECPNRC (P<0.001; r =0.411). Except total digestible nutrients and AECPNRC, the amide-I area did not show significant correlations with DVE/OEB and NRC predicted protein fractions. This study shows that molecular spectroscopy can be potentially used as a rapid tool to quantify protein molecular makeup and screen the protein nutritive value of forage corn.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.022
      Issue No: Vol. 191 (2017)
       
  • Nonadiabatic dynamics simulation of photoisomerization mechanism of the
           second stablest isomer of N-salicilydenemethylfurylamine
    • Authors: Aihua Gao; Jianpeng Li; Dehua Wang; Xiaoguang Ma; Meishan Wang
      Pages: 315 - 324
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Aihua Gao, Jianpeng Li, Dehua Wang, Xiaoguang Ma, Meishan Wang
      The photoisomerization processes of the second stablest isomer in the aromatic Schiff base, N-salicilydenemethylfurylamine, in the gas phase have been studied by static electronic structure calculations and surface-hopping dynamics simulations based on the Zhu-Nakamura theory. Various stable structures are obtained in the optimization because of different orientations of methyl-furyl part with respect to the salicylaldimine part and different orientations of hydroxy group with respect to the benzene ring. Upon photoexcitation into the first excited state, bond isomerization in the salicylaldimine part is completely suppressed until the strong excited-state hydrogen bond is broken. The decay pathway involves two excited-state minima, one in cis-enol form and the other in cis-keto form. After the excited-state proton transfer, twists of bonds lead to a conical intersection between the ground and excited states. After internal conversion around a conical intersection, the molecule is stabilized in cis- or trans-keto form. If the reverse hydrogen transfer process occurs in the ground state, the molecule will finally end up in the cis-enol region. The cis-keto and trans-keto isomers are observed as photoproducts. According to our full-dimensional nonadiabatic dynamics simulations, we find the excited-state intramolecular proton transfer and torsions of three single bonds in the chain to be responsible for photoisomerization of the second stablest isomer of N-salicilydenemethylfurylamine.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.041
      Issue No: Vol. 191 (2017)
       
  • Structural, photophysical, and theoretical studies of imidazole-based
           excited-state intramolecular proton transfer molecules
    • Authors: Sivaraman Somasundaram; Eswaran Kamaraj; Su Jin Hwang; Sanghyuk Park
      Pages: 325 - 335
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Sivaraman Somasundaram, Eswaran Kamaraj, Su Jin Hwang, Sanghyuk Park
      Imidazole-based excited state intramolecular proton transfer (ESIPT) blue fluorescent molecules, 2-(1-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Cl) and 2-(1-(4-bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Br) were designed and synthesized by Debus-Radziszewski method through a one-pot multicomponent reaction in high yield. The synthesized compounds were fully characterized by 1H NMR, 13C NMR, FT-IR, FT-Raman, GC-Mass, and elemental analysis. The molecular structures in single crystal lattice were studied by X-ray crystallographic analysis. Because of the intramolecular hydrogen bonding, hydroxyphenyl group is planar to the central imidazole ring, while the other phenyl rings gave distorted conformations to the central heterocyclic ring. BHPI-Cl and BHPI-Br molecules showed intense ESIPT fluorescence at 480nm, because the two twisted phenyl rings on 4- and 5-positions have reduced intermolecular interaction between adjacent molecules in each crystal through a head-to-tail packing manner. Quantum chemical calculations of energies were carried out by (TD-)DFT using B3LYP/6-31G(d, p) basis set to predict the electronic absorption spectra of the compounds, and they showed good agreement between the computational and the experimental values. The thermal analyses of the synthesized molecules were also carried out by TGA/DSC method.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.023
      Issue No: Vol. 191 (2017)
       
  • Enhanced Sensitivity to Detection Nanomolar Level of Cu2+ Compared to
           Spectrophotometry Method by Functionalized Gold Nanoparticles: Design of
           Sensor Assisted by Exploiting First-order Data with Chemometrics
    • Authors: Zolaikha Rasouli; Raouf Ghavami
      Pages: 336 - 344
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Zolaikha Rasouli, Raouf Ghavami
      A simple, sensitive and efficient colorimetric assay platform for the determination of Cu2+ was proposed with the aim of developing sensitive detection based on the aggregation of AuNPs in presence of a histamine H2-receptor antagonist (famotidine, FAM) as recognition site. This study is the first to demonstrate that the molar extinction coefficients of the complexes formed by FAM and Cu2+ are very low (by analyzing the chemometrics methods on the first order data arising from different metal to ligand ratio method), leading to the undesirable sensitivity of FAM-based assays. To resolve the problem of low sensitivity, the colorimetry method based on the Cu2+-induced aggregation of AuNPs functionalized with FAM was introduced. This procedure is accompanied by a color change from bright red to blue which can be observed with the naked eyes. Detection sensitivity obtained by the developed method increased about 100 fold compared with the spectrophotometry method. This sensor exhibited a good linear relation between the absorbance ratios at 670 to 520nm (A670/520) and the concentration in the range 2–110nM with LOD=0.76nM. The satisfactory analytical performance of the proposed sensor facilitates the development of simple and affordable UV–Vis chemosensors for environmental applications.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.027
      Issue No: Vol. 191 (2017)
       
  • A molecularly imprinted dual-emission carbon dot-quantum dot mesoporous
           hybrid for ratiometric determination of anti-inflammatory drug celecoxib
    • Authors: Mohammad Amjadi; Roghayeh Jalili
      Pages: 345 - 351
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Mohammad Amjadi, Roghayeh Jalili
      We report on a ratiometric fluorescent sensor based on dual-emission molecularly imprinted mesoporous silica embedded with carbon dots and CdTe quantum dots (mMIP@CDs/QDs) for celecoxib (CLX) as target molecule. The fluorescence of the embedded CDs is insensitive to the analyte while the green emissive QDs are selectively quenched by it. This effect is much stronger for the MIP than for the non-imprinted polymer, which indicates a good recognition ability of the mesoporous MIP. The hybrid sensor also exhibited good selectivity to CLX over other substances. The ratio of the intensity at two wavelengths (F550/F440) proportionally decreased with the increasing of CLX concentration in the range of 0.08–0.90μM. A detection limit as low as 57nM was achieved. Experimental results testified that this sensor was highly sensitive and selective for the detection of CLX in human serum samples.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.026
      Issue No: Vol. 191 (2017)
       
  • Dielectric spectroscopy study of water hyacinth collected from different
           media
    • Authors: Ragab Mahani; Fatma Atia; Mohammed M. Al Neklawy; Amin Fahem
      Pages: 352 - 356
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Ragab Mahani, Fatma Atia, Mohammed M. Al Neklawy, Amin Fahem
      X-ray fluorescence (XRF) study has been shown that the water hyacinth plant is an effective tool for the removals of heavy metals (As, Ba, Cr, Cu, Ni, Pb, Rb, Sr, Zn and Zr) and metal oxides (SiO2, K2O, CaO, Al2O3, Fe2O3, MgO, Na2O, MnO, P2O5, SO3 and TiO2) from agriculture (media 1) and agriculture wastewaters drainage polluted with municipal wastewater (media 2). As a general description, the heavy metals and metal oxides were found at higher levels in the plant collected from media 1 than those in the plant collected from media 2. Similarly, these pollutants were found at higher levels in the plant roots than those in the plant shoots. The dielectric properties were investigated for the plant samples before (control) and after treating by microwave heating power. They were found at higher values in the control roots than those in the control shoots. Furthermore, the properties were found at relatively higher values in the control roots collected from media 1 (ε′=13 at 103 Hz) than those in the control roots collected from media 2 (ε′=9 at 103 Hz). The electrical conductivity of the microwave treated samples remarkably increased due to appearance of OH group through which the plant interacts with heavy metals. Accordingly, the pollutants removing ability could be enhanced upon treating the plant by microwave heating power. The plant-pollutant mixture behaves like highly conductive disordered polymers. The conductivity and dielectric properties of all plant samples are dominated by the media and concentration of pollutants.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.024
      Issue No: Vol. 191 (2017)
       
  • Optical limiting properties of 3,5-dipyrenylvinyleneBODIPY dyes at 532nm
    • Authors: Gugu Kubheka; Kayode Sanusi; John Mack; Tebello Nyokong
      Pages: 357 - 364
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Gugu Kubheka, Kayode Sanusi, John Mack, Tebello Nyokong
      The optical limiting (OL) properties of 3,5-dipyrenylvinyleneBODIPY dyes that contain both electron withdrawing and donating moieties have been investigated by using the z-scan technique at 532nm in the nanosecond pulse range. The extension of the π-conjugation at the 3,5-positions with pyrenylvinylene groups results in a ca. 200nm red shift of the main BODIPY spectral band to ca. 700nm, so there is relatively weak absorbance at 532nm under ambient light conditions. Reverse saturable absorbance (RSA) profiles are observed in response to incident pulsed laser light that is consistent with a two photon absorption-assisted excited state absorption (ESA) mechanism in CH2Cl2 solution and when the dyes are embedded in poly(bisphenol carbonate A) (PBC) polymer thin films. This demonstrates that 3,5-divinyleneBODIPY dyes are potentially suitable for use in OL applications, since limiting threshold fluence (Ilim) values of below 0.95Jcm−2 are observed when thin films are prepared.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.021
      Issue No: Vol. 191 (2017)
       
  • Application of wavelet and Fuorier transforms as powerful alternatives for
           derivative spectrophotometry in analysis of binary mixtures: A comparative
           study
    • Authors: Said A. Hassan; Sherif A. Abdel-Gawad
      Pages: 365 - 371
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Said A. Hassan, Sherif A. Abdel-Gawad
      Two signal processing methods, namely, Continuous Wavelet Transform (CWT) and the second was Discrete Fourier Transform (DFT) were introduced as alternatives to the classical Derivative Spectrophotometry (DS) in analysis of binary mixtures. To show the advantages of these methods, a comparative study was performed on a binary mixture of Naltrexone (NTX) and Bupropion (BUP). The methods were compared by analyzing laboratory prepared mixtures of the two drugs. By comparing performance of the three methods, it was proved that CWT and DFT methods are more efficient and advantageous in analysis of mixtures with overlapped spectra than DS. The three signal processing methods were adopted for the quantification of NTX and BUP in pure and tablet forms. The adopted methods were validated according to the ICH guideline where accuracy, precision and specificity were found to be within appropriate limits.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.08.039
      Issue No: Vol. 191 (2017)
       
  • A turn-on supramolecular fluorescent probe for sensing benzimidazole
           fungicides and its application in living cell imaging
    • Authors: Qing Tang; Jing Zhang; Tao Sun; Cheng-Hui Wang; Ying Huang; Qingdi Zhou; Gang Wei
      Pages: 372 - 376
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Qing Tang, Jing Zhang, Tao Sun, Cheng-Hui Wang, Ying Huang, Qingdi Zhou, Gang Wei
      A cucurbit[8]uril-based turn-on supramolecular fluorescent probe between cucurbit[8]uril (Q[8]) and pyronine Y (PyY) (designated 2PyY@Q[8]) in acidic aqueous solution showed a remarkable fluorescence ‘turn-on’ response to benzimidazole fungicides such as thiabendazole, fuberidazole and carbendazim. The 2PyY@Q[8] fluorescent probe can be used to detect benzimidazole fungicides with high sensitivity and selectivity with a detection limit of ~10−8 mol/L. A good linear relationship of emission intensity at ~580nm for benzimidazole fungicides at concentrations of 0.4–5.0μmol/L was observed. The proposed sensing mechanism was investigated using 1H NMR spectroscopy combined with density functional theory calculations at the B3LYP/6-31G(d) level. The cell imaging study showed that the 2PyY@Q[8] complex could be used to image benzimidazole fungicide in prostate cancer (PC3) cells, which may help to elucidate relevant biological processes at the molecular level.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.042
      Issue No: Vol. 191 (2017)
       
  • Spectroscopic investigation on structure and pH dependent Cocrystal
           formation between gamma-aminobutyric acid and benzoic acid
    • Authors: Yong Du; Jiadan Xue; Qiang Cai; Qi Zhang
      Pages: 377 - 381
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Yong Du, Jiadan Xue, Qiang Cai, Qi Zhang
      Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00≤pH≤7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.036
      Issue No: Vol. 191 (2017)
       
  • DFT calculations for anharmonic force field and spectroscopic constants of
           YC2 and its 13C isotopologues
    • Authors: Yanliang Zhao; Meishan Wang; Chuanlu Yang; Xiaoguang Ma; Jing Li
      Pages: 382 - 388
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Yanliang Zhao, Meishan Wang, Chuanlu Yang, Xiaoguang Ma, Jing Li
      The construction of the complete third and the semi-diagonal quartic force fields including the anharmonicity of the ground state ( X ˜ 2 A 1 ) for yttrium dicarbide (YC2) is carried out employing the vibrational second-order perturbation theory (VPT2) in combination with the density functional theory (DFT). The equilibrium geometries optimization, anharmonic force field and vibrational spectroscopic constants of YC2 are calculated by B3LYP, B3PW91 and B3P86 methods. Aug-cc-pVnZ (n=D, T, Q) and cc-pVnZ-PP (n=D, T, Q) basis sets are chosen for C and Y atoms, respectively. The calculated geometry parameters of YC2 agree well with the corresponding experimental and previous theoretical results. The bonding characters of YC2 or CC are discussed. Based on the optimized equilibrium geometries, the spectroscopic constants and anharmonic force field of YC2 are calculated. Comparing with the spectroscopic constants of YC2 derived from the experiment, the calculated results show that the B3PW91 and B3P86 methods are superior to B3LYP for YC2. The Coriolis coupling constants, cubic and quartic force constants of YC2 are reasonably predicted. Besides, the spectroscopic constants and anharmonic force field of Y13C2 ( X ˜ 2 A 1 ) and Y13CC ( X ˜ 2 A ′ ) are calculated for the first time, which are expected to guide the high resolution experimental work for YC2 and its 13C isotopologues.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.016
      Issue No: Vol. 191 (2017)
       
  • Experimental conditions affecting the kinetics of aqueous HCN
           polymerization as revealed by UV–vis spectroscopy
    • Authors: Margarita R. Marín-Yaseli; Miguel Moreno; José L. de la Fuente; Carlos Briones; Marta Ruiz-Bermejo
      Pages: 389 - 397
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Margarita R. Marín-Yaseli, Miguel Moreno, José L. de la Fuente, Carlos Briones, Marta Ruiz-Bermejo
      HCN polymerization is one of the most important and fascinating reactions in prebiotic chemistry, and interest in HCN polymers in the field of materials science is growing. However, little is known about the kinetics of the HCN polymerization process. In the present study, a first approach to the kinetics of two sets of aqueous HCN polymerizations, from NH4CN and NaCN, at middle temperatures between 4 and 38°C, has been carried out. For each series, the presence of air and salts in the reaction medium has been systematically explored. A previous kinetic analysis was conducted during the conversion of the insoluble black HCN polymers obtained as gel fractions in these precipitation polymerizations for a reaction of one month, where a limit conversion was achieved at the highest polymerization temperature. The kinetic description of the gravimetric data for this complex system shows a clear change in the linear dependence with the polymerization temperature for the reaction from NH4CN, besides a relevant catalytic effect of ammonium, in comparison with those data obtained from the NaCN series. These results also demonstrated the notable influence of air, oxygen, and the saline medium in HCN polymer formation. Similar conclusions were reached when the sol fractions were monitored by UV–vis spectroscopy, and a Hill type correlation was used to describe the polymerization profiles obtained. This technique was chosen because it provides an easy, prompt and fast method to follow the evolution of the liquid or continuous phase of the process under study.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.003
      Issue No: Vol. 191 (2017)
       
  • Two novel self-assemblies of supramolecular solar cells using
           N-heterocyclic-anchoring porphyrins
    • Authors: Qian Zhang; Fang-Yuan Wu; Jia-Cheng Liu; Ren-Zhi Li; Neng-Zhi Jin
      Pages: 398 - 404
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Qian Zhang, Fang-Yuan Wu, Jia-Cheng Liu, Ren-Zhi Li, Neng-Zhi Jin
      Two novel N-substituted anchoring porphyrins (ZnPAtz and ZnPAim) have been devised and synthesized. Moreover, these two anchoring porphyrins were linked to the TiO2 semiconductor through carboxyl groups and then a zinc porphyrin ZnP was bound to the anchoring porphyrin using a zinc-to-ligand axial coordination approach. The different performances of these assemblies were compared with single anchoring porphyrin devices ZnPAtz and ZnPAim. The photoelectric conversion efficiency of the new supramolecular solar cells sensitized by ZnP-ZnPAx (x=tz, im) has been improved. The ZnP-ZnPAtz-based DSSCs provided the highest photovoltaic efficiency (1.86%). Fundamental studies showed that incorporation of these assemblies promote light-harvesting efficiency.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.046
      Issue No: Vol. 191 (2017)
       
  • Structural changes of wood during hydro-thermal and thermal treatments
           evaluated through NIR spectroscopy and principal component analysis
    • Authors: Carmen-Mihaela Popescu; Parviz Navi; María Inés Placencia Peña; Maria-Cristina Popescu
      Pages: 405 - 412
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Carmen-Mihaela Popescu, Parviz Navi, María Inés Placencia Peña, Maria-Cristina Popescu
      Spruce wood samples were subjected to different conditions of thermal and hydro-thermal treatment by varying the temperature, relative humidity and period of exposure. The obtained treated samples were evaluated using near infrared spectroscopy (NIR), principal component analysis (PCA) and hierarchical cluster analysis (HCA) in order to evidence the structural changes which may occur during the applied treatment conditions. Following this, modification in all wood components were observed, modifications which were dependent on the temperature, amount of relative humidity and also the treatment time. Therefore, higher variations were evidenced for samples treated at higher temperatures and for longer periods. At the same time, the increase in the amount of water vapours in the medium induced a reduced rate of side chains and condensation reactions occurring in the wood structure. Further, by PCA and HCA was possible to discriminate the modifications in the wood samples according to treatment time and amount of relative humidity.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.045
      Issue No: Vol. 191 (2017)
       
  • Validated spectroscopic methods for determination of anti-histaminic drug
           azelastine in pure form: Analytical application for quality control of its
           pharmaceutical preparations
    • Authors: Amal A. El-Masry; Mohammed E.A. Hammouda; Dalia R. El-Wasseef; Saadia M. El-Ashry
      Pages: 413 - 420
      Abstract: Publication date: 15 February 2018
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 191
      Author(s): Amal A. El-Masry, Mohammed E.A. Hammouda, Dalia R. El-Wasseef, Saadia M. El-Ashry
      Two simple, sensitive, rapid, validated and cost effective spectroscopic methods were established for quantification of antihistaminic drug azelastine (AZL) in bulk powder as well as in pharmaceutical dosage forms. In the first method (A) the absorbance difference between acidic and basic solutions was measured at 228nm, whereas in the second investigated method (B) the binary complex formed between AZL and Eosin Y in acetate buffer solution (pH3) was measured at 550nm. Different criteria that have critical influence on the intensity of absorption were deeply studied and optimized so as to achieve the highest absorption. The proposed methods obeyed Beer's low in the concentration range of (2.0–20.0μg·mL−1) and (0.5–15.0μg·mL−1) with % recovery±S.D. of (99.84±0.87), (100.02±0.78) for methods (A) and (B), respectively. Furthermore, the proposed methods were easily applied for quality control of pharmaceutical preparations without any conflict with its co-formulated additives, and the analytical results were compatible with those obtained by the comparison one with no significant difference as insured by student's t-test and the variance ratio F-test. Validation of the proposed methods was performed according the ICH guidelines in terms of linearity, limit of quantification, limit of detection, accuracy, precision and specificity, where the analytical results were persuasive.
      Graphical abstract image

      PubDate: 2017-10-26T12:52:35Z
      DOI: 10.1016/j.saa.2017.10.049
      Issue No: Vol. 191 (2017)
       
 
 
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