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Quzhou, China

Lu Q.,Chenguang Biotech
Journal of Agricultural and Food Chemistry | Year: 2012

Recently, rhodamine B (RhB) in paprika and chilli has attracted much attention. Almost all the literature has deemed that the detectable RhB was attributed to malicious intents in the fabrication process. However, the occurrence of increasing cases with ultratrace levels of RhB was difficult to understand on the basis of that statement. Here, we report on the discovery of environmental RhB contamination in paprika during its vegetation process. Samples including paprika, soils, and stems collected from seven fields in the Xinjiang Region, China, were detected by ultraperformance liquid chromatography-tandem mass spectrometry. Far from any anthropogenic addition, the ultratrace RhB concentrations in all the paprika samples provided unambiguous evidence that environmental RhB contamination in paprika had really occurred over its growth period. Further illation suggests that the soil contaminated by RhB is one of the major contamination sources and that there may be a degradation of RhB in paprika during the late maturation stage. The discovery has significant implications for re-evaluating the origin of the RhB in paprika- and chilli-containing products. © 2012 American Chemical Society. Source

Yan H.,Hebei University | Han Y.,Hebei University | Du J.,Chenguang Biotech
Analytical Methods | Year: 2012

A new solid-phase extraction and dispersive liquid-liquid microextraction (SPE-DLLME) method coupled with gas chromatography electron capture detection (GC-ECD)was established for the detection of cypermethrin and permethrin in river water. The samples were firstly extracted using a large-volume SPE procedure and the eluents of SPE were further purified and enriched by the following DLLME. Good linearity was observed in the range of 0.015-3.87 μg L -1 for cypermethrin and 0.065-16.2 μg L -1 for permethrin with the correlation coefficient (r) ≥ 0.9995. The limits of detection based on S/N = 3 were 0.48 and 3.81 ng L -1 for cypermethrin and permethrin, respectively. Under optimized conditions, the enrichment factors for cypermethrin and permethrin were 1545- and 2138-fold, respectively. The developed method was successfully used to detect the two pyrethroid residues in river water samples. This journal is © The Royal Society of Chemistry 2012. Source

Qiao F.,Baoding University | Du J.,Chenguang Biotech
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2013

A simple and selective molecularly imprinted matrix solid-phase dispersion (MI-MSPD) method coupled with high performance liquid chromatography (HPLC) ultraviolet detection was developed for rapid screening of clenbuterol hydrochloride (CH) in chicken samples. The new molecularly imprinted microspheres (MIM) were synthesized by using butylamine and chloroaniline as dummy template with aqueous suspension polymerization and revealed good affinity to CH in aqueous solution. The application of the obtained MIM as sorbent of matrix solid-phase dispersion (MSPD) improved the selectivity of extraction procedure and avoided the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity of CH was obtained in a range of 0.059-18.30μgmL-1 with the correlation coefficient (R) of 0.9996. The recoveries of CH at three spiked levels were ranged from 92.0 to 99.1% with the relative standard deviation less than 4.0% (n=3). The presented MI-MSPD-HPLC method combined the superiority of MIM and MSPD, and therefore could be potentially applied for the determination of CH in complicated biological samples. © 2013 Elsevier B.V. Source

Wu N.-Y.,Shangqiu Normal University | Gao W.,Chenguang Biotech | He X.-L.,South China Normal University | Chang Z.,Shangqiu Normal University | Xu M.-T.,Shangqiu Normal University
Biosensors and Bioelectronics | Year: 2013

A direct electrochemical DNA biosensor based on zero current potentiometry was fabricated by immobilization of ssDNA onto gold nanoparticles (AuNPs) coated pencil graphite electrode (PGE). One ssDNA/AuNPs/PGE was connected in series between clips of working and counter electrodes of a potentiostat, and then immersed into the solution together with a reference electrode, establishing a novel DNA biosensor for specific DNA detection. The variation of zero current potential difference (ΔEzcp) before and after hybridization of the self-assembled probe DNA with the target DNA was used as a signal to characterize and quantify the target DNA sequence. The whole DNA biosensor fabrication process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy with the use of ferricyanide as an electrochemical redox indicator. Under the optimized conditions, ΔEzcp was linear with the concentrations of the complementary target DNA in the range from 10nM to 1μM, with a detection limit of 6.9nM. The DNA biosensor showed a good reproducibility and selectivity. Prepared DNA biosensor is facile and sensitive, and it eliminates the need of using exogenous reagents to monitor the oligonucleotides hybridization. © 2012 Elsevier B.V.. Source

Chenguang Biotech | Date: 2011-12-31

Disclosed a process for preparing a xanthophyll crystal, comprising: dissolving the plant extract containing a xanthophyll ester in n-hexane, then filtering the mixture; adding acetone to the filtrate, filtering and collecting a filter cake; mixing the filter cake with soybean oil and ethanol uniformly; saponifying the mixed solution with alkaline aqueous solution; then adding an acidic solution thereto until the mixed solution becomes acidic, concentrating under reduced pressure to obtain a pasty substance; adding n-hexane to the pasty saponified product, standing still and then conducting a solid-liquid separation; washing the resulting solid substance with deionized water; adding a mixed solvent to the washed solid substance, dissolving it with stirring; and then adding n-hexane thereto and standing still to recrystallize. According to the application, organic solvents are used to treat the plant extract and remove non-xanthophyll ester compounds in order to improve the efficiency of the saponification reaction; the saponified solution is concentrated under acidic condition at reduced pressure, then extracted with an organic solvent for saving water; purifying a xanthophyll crystal with a mixed solvent in order to significantly increase the purity of a xanthophyll crystal and proportion of trans-xanthophyll.

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