Bin Chen

Northwest University, Ch’ang-an, Shaanxi, China

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Publications (8)20.91 Total impact

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    ABSTRACT: The simultaneous determination of two binding parameters for metal ions on immobilized metal affinity chromatography column was performed by frontal chromatography. In this study, the binding parameters of Cu(2+) to l-glutamic acid were measured, the metal ion binding characteristics of the complex ligand were evaluated. The linear correlation coefficients were all greater than 99%, and the relative standard deviations of two binding parameters were 0.58 and 0.059%, respectively. The experiments proved that frontal chromatography method was accurate, reproducible, could be used for determining the metal binding parameters of the affinity column. The effects of buffer pH, type and concentration on binding parameters were explored by uniform design experiment. Regressing, matching and residual analyses of the models were performed. Meanwhile, the optimum binding conditions of Cu(2+) on the l-glutamic acid-silica column were obtained. Under these binding conditions, observation and regression values of two parameters were similar, and the observation values were the best. The results demonstrated that high intensity metal affinity column could be effectively prepared by measuring and evaluating binding parameters using frontal chromatography combined with a uniform design experiment. The present work provided a new mode for evaluating and preparing immobilized metal affinity column with good metal binding behaviors. This article is protected by copyright. All rights reserved.
    No preview · Article · Dec 2015 · Journal of Separation Science
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    ABSTRACT: During pretreatment process for oil sample, charring and ashing processes of oil in AOCS Official Method Ca 12-55 were improved. Oil was pretreated with concentrated sulfuric acid and potassium hydroxide instead of zinc oxide. As a result, soluble phosphate was obtained in a short time, the subsequent steps were also simplified. Firstly, phosphorus contents were measured, then the equivalent phosphatide contents in oil samples were calculated, RSD (relative SD) was only 1.03%. According to the spiking experiments at low, middle and high concentration levels, recoveries were between 97.03 and 100.99%, RSD were all less than 1.57% (n = 5). The method was applied for determining the equivalent phosphatide content of different types of oils. Compared with AOCS Official Method Ca 12-55, the improved method can provide a more effective means for detecting and analyzing the phosphorus or the equivalent phosphatide content in vegetable oils.Practical applications: In theory, the applicable scope of the improved method should be consistent with that of AOCS Official Method Ca 12-55, that is, the method is also suitable for detecting phosphorus or the equivalent phosphatide content in crude, degummed and refined vegetable oils. However, the promotion of the method should be based on more experimental data from various vegetable oils.
    No preview · Article · May 2014 · European Journal of Lipid Science and Technology
  • Bin Chen · Wusheng Wang · Xiaoxun Ma · Chen Wang · Rong Li
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    ABSTRACT: The mechanisms of glycerol adsorption from biodiesel onto the sulfonated resins in both the hydrogen form (1180H) and sodium form (1180Na) were investigated. 1180H displayed higher adsorption capacity of glycerol in comparison to 1180Na. Parameters from the four isotherm models indicated that the adsorption process for 1180H was non-ideal, physical, and endothermic but exothermic for 1180Na. The values of Gibbs free energy change (ΔG0) and entropy change (ΔS0) suggested that the adsorption processes for both 1180H and 1180Na occurred spontaneously with an increase in randomness of the system. The isosteric heats of adsorption (ΔHX) for glycerol on both 1180H and 1180Na implied that interactions between the glycerol molecules and these modified resins were dominated by strong hydrogen bonding and that there existed an adsorbate–adsorbate mutual attractive interaction. The existence of hydrogen bonding was also confirmed by infrared spectra.
    No preview · Article · Oct 2012 · Energy & Fuels
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    ABSTRACT: The adsorption isotherm data of glycerol from biodiesel (FAME, fatty acid alkyl esters) onto the sulfonated adsorbent were obtained via batch equilibrium tests at different temperatures in the range of 303–323 K. Subsequently, these data were fitted by four isotherm models. Freundlich isotherm model was the best fitted (r2 > 0.98), and the model parameter 1/n implied that the adsorption process was favorable. For the Dubinin–Radushkevich (D-R) isotherm model, the model parameter QD decreased with increasing temperature, and the mean free energy of sorption (E) was less than 8 kJ mol–1. The results of QD and E reflected the exothermic and physical properties of the adsorption process, respectively. The negative values of Gibbs free energy change (ΔG0) and enthalpy change (ΔH0) indicated that the adsorption occurs spontaneously with an exothermic nature, while the positive values of entropy change (ΔS0) suggested the increase in randomness at the solid–liquid interface during adsorption. The isosteric heat of adsorption (ΔHX) suggested that strong hydrogen bonding between glycerol and the −SO3– groups of the sulfonated adsorbent dominated the adsorption process and that there existed adsorbate–adsorbate mutual attractive interaction. Furthermore, the existence of hydrogen bonding was also confirmed by infrared spectra.
    No preview · Article · Sep 2012 · Industrial & Engineering Chemistry Research
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    ABSTRACT: The chromatographic behaviors of proteins on iminodiacetic acid (IDA) column with and without immobilized metal ion were examined in detail. Comparing the effects of pI, solution pH, and salt concentration on retention of proteins in cation-exchange chromatography (CEC) and metal chelate affinity chromatography (MCAC), the retention mechanism of proteins was investigated in MCAC. By aid of observing the retention characteristics of proteins on naked IDA and metal chelate columns in high concentration salt-out salt solution, the hydrophobic interaction in MCAC and the influence of metal ion on it were proved. In terms of the comparison of the thermodynamics of proteins in CEC and MCAC, the thermostability, the conformational change entropy Δ(ΔS0) and enthalpy Δ(ΔH0), compensation temperature β, the driving force and caloritic effect of proteins in MCAC were discussed. The identity of retention mechanism at protein thermal denaturation in CEC and MCAC was demonstrated by using the compensation relationship between ΔH0 and ΔS0.
    Preview · Article · Apr 2011
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    ABSTRACT: An aminocarboxy aspartic acid-bonded silica (Asp-Silica) stationary phase was synthesized using L-aspartic acid as ligand and silica gel as matrix. The standard protein mixtures were separated with prepared chromatographic column. The effects of solution pH, salt concentration and metal ion on the retention of proteins were examined, and also com-pared with traditional iminodiacetic acid-bonded silica (IDA-Silica) column. The results show that Asp-Silica column exhibited an excellent separation performance for proteins. The retention of proteins on Asp-Silica stationary phase was consistent with electrostatic characteristic of cation-exchange. The stationary phase displayed typical metal chelate property after fixing copper ion (II) on Asp-Silica. Under competitive eluting condition, protein mixtures were effec-tively isolated. Asp ligand showed better ion-exchange and metal chelating properties as compared with IDA ligand.
    Preview · Article · Feb 2011 · Bulletin- Korean Chemical Society
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    ABSTRACT: A novel silica-based metal chelate stationary phase, L-glutamic acid-copper(II) (L-Glu-Cu(II)), was synthesized. Effects of the immobilized metal ion, the pH of the solution, and competitive agents on chromatographic behavior of proteins were investigated on prepared chelate column. The coordination role of proteins on L-Glu-Cu(II) column was demonstrated. Optimal separation conditions for proteins on L-Glu-Cu(II) column were discussed. According to the established chromatographic conditions, protein mixtures were effectively separated. Separation performance of proteins and the leakage of Cu2+ on L-Glu-Cu(II) column were discussed and compared with the traditional iminodiacetic acid-copper(II) (IDA-Cu(II)) column. Separation performance of L-Glu-Cu(II) column for proteins was superior to that of the IDA-Cu(II) column. Under a proper eluting condition, a less amount of Cu2+ was leaked from the L-Glu-Cu(II) column as compared with IDA-Cu(II) column.
    No preview · Article · Jan 2011 · Separation Science and Technology
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    ABSTRACT: Candida antarctica lipase was immobilized by an adsorption and cross-linking method with NW-ZT2 and by modification-coupled method with a silica-PEG gel. The final product silica-PEG-lipase was confirmed by IR spectra. The optimum pH value, the optimum temperature, the thermo-stabilities and operational stabilities for two kinds of immobilized lipase were also determined. Results show that the silica-PEG-lipase gel was superior to the lipase immobilized by adsorption and cross-linking, however both are viable for use in transesterification reactions.
    No preview · Article · Sep 2010 · Biotechnology advances