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Liu W.,Liaoning University of Traditional Chinese Medicine | Liu W.,Peking University | Wu H.-J.,Peking University | Wu H.-J.,Inner Mongolia University for Nationalities | And 9 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2013

In this study, we modified the preparation of barium fluoride fine particles by a reaction between sodium fluoride and barium chloride. However, the experimental result turned out that the yield of BaF2 is rather low. By inductive coupled plasma(ICP) and X-ray diffraction(XRD) analysis, we found barium fluorochloride was produced with barium fluoride in the reaction. During the washing of precipitates, barium fluorochloride was dissolved in water with low concentration of Cl- and F-, leading to the lost of barium ions and low yield of BaF2. To solve the problem, aqueous solution of NaF was used to wash the product of the reaction between barium chloride and sodium fluoride. Both XRD and ICP results confirmed that barium fluorochloride converted into barium fluoride. Hence, the yield of barium fluoride increases significantly. The average diameter of the BaF2 particles is around 100 nm by SEM and nanometer particle size analyzer. We used settlement volatilization method to prepare TLC plate without using polymeric adhesive. TLC experiments prove that the TLC plate using BaF2 fine particles as stationary phase can separate the mixture of Rhodamine B and Malachite green. FTIR analysis confirms that the FTIR spectra of the separated Rhodamine B and Malachite green spots are in good agreement with the FTIR spectra of pure Rhodamine B and Malachite green. Source


Zhu Q.,Liaoning University of Traditional Chinese Medicine | Zhu Q.,Peking University | Su X.,Linyi Product Quality Supervision and Inspection of Shandong Province | Wu H.-J.,Peking University | And 6 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use AgI fine particles as stationary phase of TLC plate. The reasons are as follows: Silver iodide fine particles have no absorbance in an IR region between 4000 and 800 cm -1, therefore, the interference caused by IR absorption of stationary phase can be removed. Moreover, silver iodide is stable and insolvable in water and organic solvents and thus it will not be destroyed by mobile phase or react with samples during the TLC separation. To improve TLC separation efficiency and quality of FTIR spectra during the TLC/FTIR analysis, the size of AgI particles should be below 500 nm. We used orthogonal design approach to optimize the experimental condition to AgI particles so that the average size of AgI particles is around 100 nm. No absorption of impurity or adsorbed water were observed in FTIR spectrum of the AgI particles the authors used "settlement volatilization method" to prepare TLC plate without using polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using AgI fine particles as stationary phase can separate mixtures of rhodamine B and bromophenol blue successfully. Applications of silver iodide fine particles as stationary phase have bright perspective in the development of in-situ TLC/FTIR analysis techniques. Source


Zhang J.,Liaoning University of Traditional Chinese Medicine | Zhang J.,Peking University | Guo R.,Peking University | Kang T.-G.,Liaoning University of Traditional Chinese Medicine | And 6 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

In the present work, computer simulation was performed on a model chemical system where two solutes (denoted as P and Q, respectively) are dissolved in the same solution. Under intermolecular interaction between P and Q, part of P undergoes subtle structural variation and converts into U while part of Q converts into V. The strength of intermolecular interaction can be characterized by the corresponding equilibrium constant K. Our preliminary studies indicate that the S/N ratio of cross peak increases considerably as n increases. Moreover, the S/N ratio of the cross peak from the asynchronous spectra can be improved significantly when the suitable concentrations of P and Q are adopted. This work is helpful for a selection of suitable concentration sequence to maximize S/N ratio of cross peaks in the 2D asynchronous spectra generated by using the DAOSD approach proposed in our previous study so that weak intermolecular interaction can be probed. ©, 2015, Science Press. All right reserved. Source


Zhang X.,Liaoning University of Traditional Chinese Medicine | Zhang X.,Peking University | He A.-Q.,Peking University | Kang T.-G.,Liaoning University of Traditional Chinese Medicine | And 4 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014

The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol·L-1 acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease comparedwith pure 2-deoxy-ribose and fructose. In the XPS spectra, the 1s peaks of 2-deoxy-ribose, strong sub peak at 286.05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C 1s peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1600 cm-1, indicating that C=C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency. Source


Guo L.,Liaoning University of Traditional Chinese Medicine | Guo L.,Peking University | Huang K.,CAS Institute of Process Engineering | Guo R.,Peking University | And 8 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

We reported a new super-concentrated hydrochloric acid system prepared by using tri-n-butyl phosphate (TBP)-constructed reversed micelles at ambient temperature and pressure. According to the titration result, the molar ratio of H+ to H2O (denoted as nH+/nH2O) in the super-concentrated HCl range from 0.50 to 1.50 which are higher than that in saturated aqueous HCl bulk solution (0.28). Significant a moment of hydrochloric acid is confined in W/O reversed micelles. Therefore, the behavior and status of HCl are different from those of conventional bluk solution. FTIR spectroscopic results demonstrate that a significant amount of HCl remains in the molecular form rather than being ionized into H+ and Cl-. Thus, super-concentrated HCl provides an extraordinary chemical environment which may have significant influence on certain substances. We found that the color of the solution is reddish brown when copper ion is dissolved in super-concentrated HCl, while the color of the saturated HCl aqueous solution (37 Wt%) containing copper ion is green. That is to say, the copper ions exist in a special state under the unique chemical environment of super-concentrated HCl. UV-Vis-NIR spectra indicate that both d-d transition band and charge transfer transition band of copper ions in super-concentrated HCl solution underwent significant variations. In addition, copper ions also have obvious influence on the hydrogen bond network among HCl in the super-concentrated HCl solution. Remarkable variation is introduced in the H-Cl stretching band in FTIR spectra. ©, 2015, Science Press. All right reserved. Source

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