Application of Two-Dimensional Correlation UV-Vis Spectroscopy in Chinese Liquor Moutai Discrimination

Chinese liquor Moutai is the “National alcoholic drink” in China and plays a very important role of social activities in Chinese people’s life. In pursuit of high profits, some illegal counterfeit Moutai liquors have begun to appear in the market. Therefore, it is an urgent need for new techniques to discriminate the genuine and counterfeit Moutai liquor. In this work, the conventional Ultraviolet-Visible (UV-Vis) spectroscopy and two-dimensional correlation UV-Vis spectroscopy are applied to obtain the UV-Vis characteristic of Moutai liquor and counterfeit one, respectively. The experimental results reveal that the conventional UV-Vis spectra of the genuine and counterfeit Moutai liquor are similar. However, the two-dimensional correlation UV-Vis spectra of them are different and this method would be applied to differentiate the counterfeit Moutai liquor from the genuine Moutai liquor. Compared with conventional methods, this novel method has the advantages of easy operation, simple instrumentation and direct recognition, which make it a potential tool in the fields of food safety.

Sensitivity Enhancement in Uranium Determination by UV-Visible Spectroscopy Using Ion Imprinted Polymer

There is need to determination of uranium concentration at ppb level in environmental matrices.Due to low sensitivity of FAAS,UV-Visible Spectroscopy is generally used as measurement technique.In this study,ion-imprinted polymers(IIP)were prepared for uranyl ion(imprint ion)by formation of ternary(salicylaldoxime and 4-vinylpyridine)complex in 2-methoxy ethanol(porogen)following copolymerization with methacrylic acid(MAA)as a functional monomer and ethylene glycol dimethacrylate(EGDMA)as crosslinking monomer using 2,2-azobisisobutyronitrile as initiator.The synthesized polymers were characterized by FTIR and TGA analysis.ArsenazoⅢin 3M HClO_4 was used as complexing agent in the measurement step.The optimal pH for preconcentration was found to be between 3.5~6.5values.The developed method was applied to uranium(Ⅵ)determination in natural water samples.

UV-Vis Spectroscopy Study on Interaction between Microperoxidase-11 and Pr Ion Under Acid Rain Stress

Interaction between rare earth ion praseodymium (Pr(Ⅲ)) and MP11 with/without hydrogen ion (H +) in different media( aqueous, phosphate buffer, physiological condition) were studied by UV Vis spectroscopy. All the results indicate that Pr(Ⅲ) interacts with MP11, increasing the non planarity of porphyrin periphery, leading MP11 to form two conformations when titrated by Pr(Ⅲ). Excessive Pr(Ⅲ) acts as a contaminant in living organism. H + and Pr(Ⅲ) have antagonistic effect on MP11, suggesting that at suitable concentration under physiological conditions, Pr(Ⅲ) can be used as biomodulator in protecting plants from acid rain stress or in rehabilitating the harm.

Raman and UV-Vis Spectroscopy Applied to the Analysis of Liver Tissues from Rats with Myocardial Ischemia Induced by Isoproterenol

The application of the laser Raman spectroscopic（LRS） technique for the analysis of liver tissues from rats with myocardial ischemia induced by isoproterenol（ISO） was described.Animal model of myocardial ischemia was established for rats induced by ISO.Rats were randomly divided into four groups as normal group and myocardial ischemia groups.We observed the successful myocardial ischemia model via serum enzymes levels and hematoxylin-eosin（HE） staining,and detected the liver tissue of the rats from normal group and liver tissue of the rats from myocardial ischemia groups via UV-Vis spectroscopy（UV-Vis） and LRS,and the changes of the absorbance spectra were compared in the above four different groups.The results show that ISO can induce rat myocardial ischemia successfully.The spectrum of normal liver tissue supernatant exhibits a strong absorption band at 968 nm,but no absorption band appears in the spectra of liver tissue supernatant solutions from the rats with myocardial ischemia induction after 2,12 and 72 h presented at 968 nm.LRS results show that Raman intensities of the precipitates suffered from ISO-treatment after 2,12 and 72 h were obviously increased compared with that of the precipitate of the liver tissue of the normal rats suffered from 0.9 g/L normal saline（NS） treatment.These results indicate that LRS and UV-Vis can be harmless,nondestructive,rapid and effective methods for analyzing different pathological specimens of liver tissue from myocardial ischemia rats.

Electrocatalytic Oxidation of Hypophosphite on Nickel Electrode ──In Situ UV-Vis Spectroscopic study

The electrocatalytic oxidation of hypophosphite on a nickel electrode has been studiedby means of in site UV-Vis subtractive reflectance spectroscopy. An absorbency band around 245um . which was ascribed to the formation of an intermediate, PHO2-, was observed in theelectrocatalytic oxidation process. Accordingly, the electrocatalytic oxidation of hypophosphitemight undergo a H abstraction of hypophosphite from the P-H bond to form the phosphoruscentred radical PHO2-, which is subsequently electrooxidized to the final product, phosphite.

Quality Control of Tramadol in Kisangani: Development, Validation, and Application of a UV-Vis Spectroscopic Method

Context: Substandard and falsified medicines are circulating in low-income countries mostly without any control. We availed a simple and not expensive UV-Vis spectroscopic method to evaluate the quality of tramadol in Kisangani before and during the Covid-19 period. Methods: For the analytical quantitative method, an experimental design was applied to set up the optimal levels of the selected factors, namely, pH of dissolution medium, type of cuvette, and wavelength. Taking into account the capsule pharmaceutical formulation within 80 - 120 μg·mL-1 concentration range, we analyzed 89 tramadol samples from pharmacies and hospitals of the six Kisangani municipalities. Results: pH showed a significant effect on absorbance, whereas quartz cuvette and wavelength did not. A typical 100 μg·mL-1 tramadol solution gave an absorbance of 0.64 at 272 nm. Validation highlighted a matrix effect observed with a 6% bias. A correction factor of 0.9372 allowed to improve the accuracy profile, which were then totally included within the 10% acceptance limits. Quality control revealed that 25 samples out of 89 were not compliant in terms of manufacturing license, registration status in DRC and content as well. Conclusion: This study showed that the strengthening of analytical strategy in Kisangani is a need.

The thermal and storage stability of bovine haemoglobin by ultraviolet-visible and circular dichroism spectroscopies

The effects of temperature,pH and long-term storage on the secondary structure and conformation changes of bovine haemoglobin（bHb） were studied using circular dichroism（CD） and ultraviolet-visible（UV-vis） spectroscopies.Neural network software was used to deconvolute the CD data to obtain the fractional content of the five secondary structures.The storage stability of bHb solutions in pH 6,7 and8 buffers was significantly higher at 4 ℃ than at 23 ℃ for the first 3 days.A complete denaturation of bHb was observed after 40 days irrespective of storage temperature or pH.The bHb solutions were also exposed to heating and cooling cycles between 25 and 65 ℃ and structural changes were followed by UVvis and CD spectroscopies.These experiments demonstrated that α-helix content of bHb decreased steadily with the increasing temperature above 35 ℃ at all pH values.The loss in a-helicity and gain in random coil conformations was pH-dependent and the greatest under alkaline conditions.Furthermore,there was minimal recovery of the secondary structure content upon cooling to 25 ℃.The use of bHb as a model drug is very common and this study elucidates the significance of storage and processing conditions on its stability.

Effect of Temperature on Optical Properties of Vegetable Oils Using UV-Vis and Laser Fluorescence Spectroscopy

UV-Vis absorption and fluorescence spectroscopy are used to test the quality and changes in the composition of extra virgin olive oil (EVOO) and canola oil (CO) with temperature. The increase of temperature caused a change in the molecular structures of both types of oils seen as a gradual decrease of intensity amplitudes of absorption and fluorescence signals. A significant alteration occurred at ≈200&#176C where almost the main spectra of pheophytin-a, b, carotenoids, lutein and vitamin E in EVOO and linoleic acid and oleic acid in CO disappeared. An independent experiment showed the output of laser changes linearly with the input in oil at constant temperature (i.e., room temperature) where the transmission values of ≈33% and ≈75% are determined for EVOO and CO respectively. However, the transmission through a heated oil exhibited a non-linear behaviour which indicates the molecular optical response to thermal changes. The effect of storage time and adulteration of oils were also evaluated.

In-situ UV-Vis Spectroscopy of Trisulfur Radicals in Lithium-Sulfur Batteries

Here we employ in-situ UV-Vis spectroscopy to monitor the sulfur redox reaction with oxygen-containing molecules as an additive,for example,biphenyl-4,4′-dicarboxylic acid(BDC).Furthermore,Raman spectrum,electron paramagnetic resonance(EPR),and electrospray ionization-mass spectrometry(ESI-MS)measurements reveal that the formation of BDC-S_(3)•^(‒)complexes can establish the long-term stability of polysulfide radicals,change the kinetics of sulfur redox reaction,and then generate decent capacity retention and rate capability.According to the density functional theory(DFT)analysis,S_(3)•^(‒)radicals are the underlying product of S_(6)^(2‒)cleavage,owing to the decreased chemical energy and the increased stability of S_(3)•^(‒)radicals through Lewis acid-base interaction.The assembled Li-S batteries with BDC additive deliver a high reversible capacity of 420 mA·h·g^(−1)over 200 cycles with over 98%Coulombic efficiency,under the current density of 0.2 C.

Crystal Growth of Cu6(Ge,Si)6O18·6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates

Low-dimensional quantum spin systems with the Cu2+ central ion are still in the focus of experimental and theoretical research. Here is reported on growth of mm-sized single-crystals of the low-dimensional S = 1/2 spin compound Cu6(Ge,Si)6O18·6H2O by a diffusion technique in aqueous solution. A route to form Si-rich crystals down to possible dioptase, the pure silicate, is discussed. Motivated by previously reported incorrect assignments of UV-VIS spectra, the assignment of dd excitations from such spectra of the hexahydrate and the fully dehydrated compound is proposed in comparison to dioptase and selected Cu(II) oxo-compounds using bond strength considerations. Non-doped cuprates as layer compounds show higher excitation energies than the title compound. However, when the antiferromagnetic interaction energy as Jz·ln(2) is taken into account for cuprates, a single linear relationship between the Dqe excitation energy and equatorial Cu(II)-O bond strength is confirmed for all compounds. A linear representation is also confirmed between 2A1g energies and a function of axial and equatorial Cu-O bond distances if auxiliary axial bonds are used for four-coordinated compounds. The quotient Dt/Ds of experimental orbital energies deviating from the general trend to smaller values indicates the existence of H2O respectively Cl−axial ligands in comparison to oxo-ligands, whereas larger Dt/Dqe values indicate missing axial bonds. The quotient of the excitation energy 2A1g by 2·2Eg-2B2g allows checking for correctness of the assignment and to distinguish between axial oxo-ligands and others like H2O or Cl−.

Investigation of Hexavalent Chromium Reduction in Strong Saline and Acidic Nitro-Phosphate Solutions

Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO2 concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .

Spectroscopic Analysis of Organophosphorus Pesticides Using Colorimetric Reactions

The UV-Vis and infrared(IR)absorption spectra of organophosphorus(OP)pesticides have been studied.A correlation in spectra was developed to optimize the OP pesticides in the environments.The spectroscopic(UV-Vis and IR)spectrum of OP pesticides like methyl parathion,malathion and parathion has been interpreted in detail.A complete calculation of the normal frequencies and absolute intensities of UV-Vis and IR absorption bands are interpreted with the help of corresponding experimental data.In the colorimetric reactions,the bands appear at 2 077,1 637,1 455,1 015,655cm^(-1) for malathion;2 081,1 639,1 316,1 015,794,683cm^(-1) for parathion;2 078,1 632,1 032,794cm^(-1) for methyl parathion were used for quantitative or qualitative analysis.All these IR spectra were acquired by averaging 100 scans at a resolution of 4cm^(-1).It is determined experimentally in the region 200~450nm for UV-Vis absorption bands and in the region 400~4 000cm^(-1) for IR absorption bands.It is concluded that the mainly optically active groups(P—OH, C=O,P=O, C—O—C,P—O—C, P=S, —OH)present in pesticides which are responsible in change in significant data for quantitative and qualitative analysis.The various optical properties like wavelength,band energy,wave number,and frequency,also are calculated.

Spectroscopic analysis of the interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl)-substituted aluminum(Ⅲ)phthalocyanines and serum albumins

The binding interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl)-substituted aluminum(Ⅲ)phthalocyanine(AIPc),and two-serum albumins(bovine serum albumin(BSA)and human serum albumin(HSA))has been investigated.AlPc could quench the intrinsic fuorescence of BSA and HSA through a static quenching process.The primary and secondary binding sites of AlPc on BSA were domainⅠandⅢof BSA.The primary binding site of AIPc on HSA was domainⅠ,and the secondary binding sites of AlPc on HSA were found at domainsⅠandⅡ.Our results suggest that AIPc readily interact with BSA and HSA implying that the amphiphilic substituents AIPc may contribute to their transportation in the blood.

Molecular interactions between anticancer drugs and iodinated contrast media: An in vitro spectroscopic study

Purpose: The purpose of this study is to assess molecular interactions between several anticancer drugs and an iodinated contrast medium by Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-Vis). Materials and Methods: Iopamidol (IPM) was used as an iodinated contrast medium, and mitomycin C (MTI), epirubicin hydrochloride (EPI), cisplatin (CDDP), 5-fluorouracil (5FU), irinotecan hydrochloride (CPT11), gemcitabine hydrochloride (dFdC), carboplatin (CBDCA), oxaliplatin (1OHP), paclitaxel hydrochloride (TAX) and docetaxel trihydrate (TXT) were used as anticancer drugs. For FT-IR, the purified IPM was mixed stoichiometrically with each anticancer drug as well as with a combination of MTI and EPI. After measuring each separated sample and the mixtures, the spectra of the mixtures were compared with the spectra of the sum of pure samples or the combination. For UV-Vis, IPM and anticancer drugs were dissolved in pure water;subsequently for the titration experiments, the mixtures were prepared by varying the molar ratio. IR absorption corresponds to stretching vibrations between atoms having covalent bonding, whereas UV-Vis spectra depend on molecular dynamics and shapes. Both UV-Vis and IR spectra change when there are molecular interactions such as aromatic ring stacking and hydrogen bonding. Result: IPM exhibited molecular interactions with MTI, EPI, CDDP, dFdC, CBDCA, 1OHP, TAX and TXT, as well as with the combination of MTI and EPI on FT-IR. However, molecular interactions were not observed on UV-Vis. Conclusion: Several anticancer drugs have molecular interactions with IPM, which could be clinically utilized for superselective intraarterial infusion chemotherapy.

Study of second-order nonlinear hyperpolarisability of all-trans-β-carotene in solutions by linear spectroscopic technique

This paper demonstrates the second-order nonlinear hyperpolarisability γ of all-trans-β-carotene in different solvents by linear spectroscopic technique that is based on resonance Raman scattering and UV-VIS （Ultraviolet-visible） absorption spectroscopy. Owing to the two-level model well describing the link that exists between the resonance Raman scattering and stimulated Raman scattering, the stimulated Raman polarisability αR can be calculated through the two-photon resonance system. The value of γ of all-trans-β-carotene in carbon bisulfide solution is 6.435×10^-33 esu （1 esu of resistance = 8.98755×10^11Ω） that is close to the true value, because the solution of all-trans-β-carotene in carbon bisulfide satisfies the rigid resonance Raman scattering condition. This method is expected to be worthy of applications to measure the second-order nonlinear hyperpolaxisability of a conjugate organic molecule.

Electrochemical and Spectroscopic Studies on Interaction between Complex of Copper(Ⅱ) with Schiff Base Ligand and DNA

The crystal structure of ([CuL(H_2O)_2](ClO_4)_2·2H_2O, CuL)(L=N-(5-sulfosalicylidene)-4′-bromoaniline) was determined by means of X-ray crystallography. The interaction between CuL and salmon sperm DNA in a 0.1 mol/L HOAc-NaOAc buffer solution(pH 5.10) was investigated by cyclic voltammetry and UV-Vis spectroscopy. A couple of redox peaks of CuL in the cyclic voltammograms(CV) can be seen at the glassy carbon electrode. It was found that the peak current of CuL decreased significantly with a negative shift of the peak potential in the presence of DNA compared with that in the absence of DNA. In addition, the decreased absorbance of CuL was observed with increasing the concentration of DNA; the absorption spectrum of an ethidium bromide(EB)-DNA system in the presence of CuL confirms that the binding mode of CuL to DNA is different from the intercalation of EB with DNA. All the experimental results indicate that CuL can bind to DNA by electrostatic binding and form a 1∶1 association complex with a binding constant of 2.72×10 4 L/mol.

Determination of Salbutamol Sulfate Content by Molecular Spectroscopy with Cu2+ as a Medium

Salbutamol sulfate was coordinated with Cu2+ when pH was 10, and the characteristic absorption peak of the complex was generated at 334 nm. The absorption intensity of the complex was in linear relation with the concentration of salbutamol sulfate. The regression equation was A=0.011 ρsalbutamol sulfate-0.123 0, correlation coefficient r=0.999 5, and the detection limit was 4.6 μg/ml. It was used for the determination of salbutamol sulfate samples successfully. The recovery rate was 100.5%-103.0%, and the RSD was 1.5%.

Spectroscopic, Kinetic Studies of Polyaniline-Flyash Composite

Polyaniline-fly ash (PANI-FA) composites were prepared by oxidative polymerization of aniline with fly ash in presence of ammonium persulphate (APS). The PANI-FA composites were prepared with different concentrations of fly ash to aniline ratio. The composites, so prepared, were characterized by UV-vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The thermal stability was studied by TGA and total weight loss of PANI, FA and PANI-FA composites having FA composition of 0.02%, 0.1%, 0.5% and 1.0% were found to be 82%, 39.%, 67% 65%, 62% and 61%, respectively. The UV-vis spectroscopy of the PANI-FA polymeric composite shows absorption maxima at 315 and 350 nm (due to π-π* transition of the benzenoid rings), and 578-712 nm (due to charge transfer excitations of the quinoid structure), which are characteristic of emeraldine base. FTIR spectra of the PANI-FA composite is similar to that of pure polyaniline (PANI) but with the bands for C=N, C=C and C-N shifted to lower wave numbers, i.e., 1585, 1494, 1327 and 1113 cm?1 due to strong interaction of Fe2O3 and PANI matrix. SEM shows the complexation of metal oxide with emaraldine base of PANI, significantly changing the aggregate state of polymeric molecular chain.

Spectroscopic Studies of Nanocomposites Based on PEO/PVDF Blend Loaded by SWCNTs

Novel nanocomposites of PEO/PVDF loaded by different contents of SWCNTs were prepared. From UV-Vis spectra, the estimated values of absorption edge, absorption coefficient, energy of tail and extinction coefficient were calculated. The exponential decay tail at low energy is due to the presence of localized states in the energy band gap. The shift of Raman spectra indicates the possibility of SWCNTs to be attached with OH group in the side chain of polymer molecules. The X-ray measurements indicate that the addition of SWCNTs is a rich amorphous region in polymeric matrices and complete complexation between PEO/PVDF blend and SWCNTs. The SEM images show smooth surface of PEO/PVDF and they become rough with single rod with a good distribution within surface region in polymeric matrices after loading SWCNTs. TEM images showed that SWCNTs were dispersed well in polymeric matrices. The broken ends of nanotubes were showing that the SWCNTs were broken apart rather than from at the fracture surface. The films show some defects like rags on the tube walls. There are some black regions in TEM images attributed to amorphous nature carbon. The prepared nanocomposites are very useful in technical application.

Analysis of Spectroscopic, Optical and Magnetic Behaviour of PVDF/PMMA Blend Embedded by Magnetite (Fe₃O₄) Nanoparticles

In the present work, magnetite (Fe3O4) nanoparticles have been prepared by a simple chemical method. Polymer nanocomposites based on the blend between poly vinylamine fluoride (PVDF) and (methyl methacrylate) (PMMA) doped with different concentrations of Fe3O4 nanoparticles have been prepared. The structural, optical, and magnetization properties of the nanocomposite samples were studied using suitable techniques. The X-ray study reflected that the cubic spinal structure of pure Fe3O4 crystal. No small peaks or ripples were found in the X-ray spectra, conforming to good dispersion of Fe3O4 within PVDF/PMMA matrices. The FT-IR analysis demonstrated the miscibility between the PVDF and PMMA blend with the interaction between the polymer blend and Fe3O4. The values of the band gap from UV-Vis study were decreased up to 4.21 eV, 3.01 eV for direct and indirect measurements, respectively. The magnetization was measured as a function of the applied magnetic field in the range of −2000 - 2000 Oersted. The curves of the magnetization indicated a paramagnetic behavior of pure Fe3O4 nanoparticles and PVDF/PMMA-Fe3O4 nanocomposites. The values of saturation magnetization for pure Fe3O4 are nearly 75 emu/g, exhibiting a paramagnetic behavior, and it is decreased with the increase of Fe3O4 content.