Hunan Entry Exit Inspection and Quarantine Bureau

Changsha, China

Hunan Entry Exit Inspection and Quarantine Bureau

Changsha, China

Time filter

Source Type

Wang L.,Hunan Entry Exit Inspection and Quarantine Bureau
Chinese Journal of Chromatography (Se Pu) | Year: 2011

A new method for the determination of antioxidants, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and tertiary butylhydroquinone (TBHQ) in plastic food package by gas chromatography-electron capture detection (ECD) was developed. The antioxidants were extracted by cyclohexane with ultrasonic extraction; separated by an HP-50 + chromatographic column (30 m × 0. 53 mm × 1 μm) and quantified by external standard method with an ECD detector. The average recoveries of antioxidants were 88% - 93%, 92% - 101% and 83% - 97% for BHT, BHA and TBHQ, respectively, at the spiking levels of 3. 00 - 10.0 mg/kg. The corresponding relative standard deviations (RSDs, n = 5) were 2.01% - 2. 89%, 2. 11% - 3. 19% and 2. 99% - 4. 02%, respectively. The limits of detection (S/N = 3) were 0. 5, 0. 5 and 0. 8 mg/kg for BHT, BHA and TBHQ, respectively. The proposed method has been applied to the analysis of 5 kinds of polymer food package. The results indicated that all the above antioxidants were found in the practical polymer food package samples. Plastic food package contained BHT and BHA with the concentrations varying from 6. 3 to 7. 8 mg/kg and rubber food package contained all the three antioxidants with the concentrations varying from 9. 3 to 28. 4 mg/kg. This method is accurate, sensitive, highly reproducible and suitable for the analysis of residual antioxidants in polymer food package.

Liang M.,Tianjin University | Su R.,Tianjin University | Qi W.,Tianjin University | Yu Y.,Tianjin University | And 2 more authors.
Journal of Materials Science | Year: 2014

A novel functional bio-nanocomposite was prepared by deposition of Ag nanoparticles onto the surface of natural eggshell membrane fibers. Practically, the functional groups exposed on the fiber surface can provide locations to anchor Ag ions when immersed into metal precursor solution. The synthesized small-sized Ag nanoparticles with uniform distribution is well decorated on the surface of interwoven fibers of eggshell membrane. The effectiveness of the as-prepared AgNPs/ESM composites as a solid phase heterogeneous catalyst has been evaluated, for the first time, on the well-known 4-nitrophenol reduction to 4-aminophenol in the presence of excess borohydride. Moreover, the kinetics of the reduction reaction was investigated at different temperatures to determine the activation energy. This work provides an important example in the introduction of natural membranes for the fabrication of functional hybrid nanocomposites which could be very useful in varying fields. © 2013 Springer Science+Business Media New York.

Liang M.,Tianjin University | Liu R.,Tianjin University | Qi W.,Tianjin University | Su R.,Tianjin University | And 3 more authors.
Food Chemistry | Year: 2013

The interaction of procyanidins with proteins has aroused extensive attention due to its important relationship with the bioavailability and astringent property of polyphenols. In the present work, we have investigated the interactions of lysozyme with procyanidin dimer (B3) using various biophysical approaches, which aims to provide insights into the mechanism of protein/polyphenol aggregation. Procyanidin B3 spontaneously binds lysozyme, inducing the multilevel structural changes in lysozyme and the formation of insoluble complexes. The relationship between lysozyme aggregation and the loss of enzymatic activity was monitored using dynamic light scattering and fluorescence quenching. The influences of two carbohydrates (gum arabic and sucrose) on lysozyme/B3 aggregation were also studied. Gum arabic effectively inhibited the formation of insoluble aggregates, but was unable to restore the fluorescence and activity of lysozyme. However, sucrose concomitantly decreased the aggregate size with the recovery of fluorescence and lysozyme activity. These results proposed two probable mechanisms by which these two carbohydrates inhibit protein/polyphenol aggregation. © 2012 Elsevier Ltd. All rights reserved.

Liang M.,Tianjin University | Wang L.,Hunan Entry Exit Inspection and Quarantine Bureau | Su R.,Tianjin University | Qi W.,Tianjin University | And 3 more authors.
Catalysis Science and Technology | Year: 2013

For the first time, we demonstrated the fabrication of silver nanoparticles (NPs) in cross-linked protein crystal hybrid material with catalytic properties using a facile chemical reduction method. The macroscopic porous lysozyme crystals can be used as excellent templates for the incorporation of Ag nanoparticles. The resulting AgNP-in-lysozyme crystal composites exhibited a good catalytic activity toward nitrophenol reduction. Notably, these catalysts could be easily recovered and reused for at least five successive cycles with almost constant activity and conversion efficiency. This journal is © 2013 The Royal Society of Chemistry.

Yu Y.,Tianjin University | Su R.,Tianjin University | Wang L.,Hunan Entry Exit Inspection and Quarantine Bureau | Qi W.,Tianjin University | He Z.,Tianjin University
Medicinal Chemistry Research | Year: 2010

Dibenzo [c,h]-[1,6] naphthyridin-6-one (ARC-111) and its analogues can exhibit potent topoisomerase I targeting and antitumor activities. Quantitative structure-activity relationship (QSAR) studies on the antitumor activity of 22 ARC-111 analogues to RPMI 8402 (expressed as pIC50) were performed by using electronic, spatial, thermodynamic, and topological descriptors based on different chemometric tools including stepwise multiple linear regression (stepwise MLR), partial least squares (PLS), and artificial neural network (ANN). QSAR equations were examined using a training set of 18 compounds and an external test set of four compounds, which was divided by cluster analysis. The ANN model was the most powerful, with a square of predictive correlation coefficient R pred 2 of 0.963 for the test set; the R pred 2 values for stepwise MLR and PLS were 0.780 and 0.729, respectively. The results obtained with these models indicated that the antitumor activity of ARC-111 analogues depends strongly on electronic factors (such as sum of E-state of H-bond acceptors, dipole moment as debyes, and total energy). © 2009 Birkhäuser Boston.

Wang G.M.,Chongqing University | Dai H.,Hunan Entry Exit Inspection and Quarantine Bureau | Li Y.G.,Chongqing University | Li X.L.,Chongqing Entry Exit Inspection and Quarantine Bureau | And 4 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2010

Trichlorfon is a thermally unstable insecticide that can be easily decomposed to dichlorvos at high temperatures. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of the residues of trichlorfon and dichlorvos in animal tissues. Trichlorfon and dichlorvos in animal tissues were extracted with dichloromethane, homogenized/shaken, concentrated, and determined by LC-MS/MS. The two insecticides can be effectively separated and individually determined. The limits of detection (LODs) of trichlorfon and dichlorvos were 0.04 and 0.07mg kg 1, respectively; the limits of quantification (LOQs) of the two insecticides were both 5 mgkg 1. The average recoveries for three spiked blank samples at 10,20 and 40mg kg 1 were in the range 85-106%, with relative standard deviations (RSDs) below 10.6%, which falls in a reasonable range for the analysis of the two insecticides in animal-derived foods. The method is fit-for-purpose for the simultaneous determination of residues of trichlorfon and dichlorvos in animal tissues. © 2010 Taylor & Francis.

Liang M.,Tianjin University | Wang L.,Hunan Entry Exit Inspection and Quarantine Bureau | Liu X.,Tianjin University | Qi W.,Tianjin University | And 4 more authors.
Nanotechnology | Year: 2013

Bio-nanomaterials fabricated using a bioinspired templating technique represent a novel class of composite materials with diverse applications in biomedical, electronic devices, drug delivery, and catalysis. In this study, Au nanoparticles (NPs) are synthesized within the solvent channels of cross-linked lysozyme crystals (CLLCs) in situ without the introduction of extra chemical reagents or physical treatments. The as-prepared AuNPs-in-protein crystal hybrid materials are characterized by light microscopy, transmission electron microscopy, x-ray diffraction, and Fourier-transform infrared spectroscopy analyses. Small AuNPs with narrow size distribution reveal the restriction effects of the porous structure in the lysozyme crystals. These composite materials are proven to be active heterogeneous catalysts for the reduction of 4-nitrophenol to 4-aminophenol. These catalysts can be easily recovered and reused at least 20 times because of the physical stability and macro-dimension of CLLCs. This work is the first to use CLLCs as a solid biotemplate for the preparation of recyclable high-performance catalysts. © 2013 IOP Publishing Ltd.

Liu Y.,Hunan University | Wu H.,Hunan University | Zhu S.,Hunan Entry Exit Inspection and Quarantine Bureau | Kang C.,Hunan University | And 4 more authors.
Chinese Journal of Chemistry | Year: 2012

A novel methodology that combines high performance liquid chromatography with photodiode-array detector (HPLC-DAD) coupled with second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm was used in determination of the effective constituents such as costunolide and dehydrocostuslactone, in plasma sample and Chinese patent medicine Xiang Sha Yang Wei (XSYW) capsule. Complicated systems such as plasma and Chinese patent medicine which have intricate components are tedious to isolate and purify. The problem that chromatographic peaks are heavily overlapped among the analytes and interferents from the background matrices can be resolved, and the satisfactory quantification results have been gained with the help of the ATLD algorithm which utilized "mathematical separation" instead of partial "physical or chemical separation". Meanwhile, HPLC-MS/MS method was used to validate the accuracy of the proposed determination method. © 2012 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yu Y.-J.,Hunan University | Wu H.-L.,Hunan University | Shao S.-Z.,Hunan University | Kang C.,Hunan University | And 4 more authors.
Talanta | Year: 2011

A novel strategy that combines the second-order calibration method based on the trilinear decomposition algorithms with high performance liquid chromatography with diode array detector (HPLC-DAD) was developed to mathematically separate the overlapped peaks and to quantify quinolones in honey samples. The HPLC-DAD data were obtained within a short time in isocratic mode. The developed method could be applied to determine 12 quinolones at the same time even in the presence of uncalibrated interfering components in complex background. To access the performance of the proposed strategy for the determination of quinolones in honey samples, the figures of merit were employed. The limits of quantitation for all analytes were within the range 1.2-56.7 μg kg -1. The work presented in this paper illustrated the suitability and interesting potential of combining second-order calibration method with second-order analytical instrument for multi-residue analysis in honey samples. © 2011 Elsevier B.V. All rights reserved.

Liang M.,Tianjin University | Jin F.,Tianjin University | Liu R.,Tianjin University | Su R.,Tianjin University | And 4 more authors.
Journal of Materials Science | Year: 2013

Inexpensive, non-toxic, and biocompatible materials that can disperse multiwall carbon nanotubes (MWCNTs) in aqueous solutions through a non-covalent approach while retaining their unique electronic and photonic properties are highly preferred. In this article, we introduce the use of an amphiphilic dipeptide derivative, aspartame, as an effective dispersing agent in preparing highly stable suspensions under ultrasonication. The results demonstrate that aspartame was absorbed by the nanotube surface possibly because of non-covalent π-π stacking between the aromatic group of aspartame and the CNT backbone. In addition, the resulting MWCNT/aspartame composites remained stably dispersed over a wide range of pH values. The chronoamperometric measurements of MWCNT/aspartame composite-coated electrodes for hydrogen peroxide demonstrated better electrochemical detection performance, as characterized by significantly enhanced step current, higher sensitivity, and reduced potential compared with bare electrodes. © 2013 Springer Science+Business Media New York.

Loading Hunan Entry Exit Inspection and Quarantine Bureau collaborators
Loading Hunan Entry Exit Inspection and Quarantine Bureau collaborators