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He Y.,University of Sichuan | Zhao L.,Test Center for Feed Quality Supervision and Inspection Chengdu | Yuan H.,University of Sichuan | Xu Z.,University of Sichuan | And 3 more authors.

In this paper, a fluorescein isothiocyanate (FITC) precolumn derivatization technique in conjunction with an HPLC-in-capillary optical fiber laser-induced fluorescence (HPLC-ICOF-LIF) detection method has been developed for determination of amino acids. The HPLC separation of FITC-labeled amino acids and the ICOF-LIF detection system are studied and optimized. Optimum separation conditions were obtained with a gradient elution program of acetonitrile and phosphate buffer (10 mM, pH 6.8). The ICOF-LIF detection system comprises a 530-μm capillary and a 380-μm optical fiber. The analyses of amino acids display excellent linear relationship between peak area and concentration with correlation coefficients greater than 0.999 and the method also provides good repeatability with RSD < 3%. The detection limits for FITC-tagged amino acids are very low and the lowest LOD for tyrosine is 51 pM. The proposed method has been successfully applied to determination of amino acids in human serum. Our developed HPLC-ICOF-LIF system is cheap, simple, stable, and sensitive which is potentially useful for the formulation analysis and bioanalysis. © 2011 Springer-Verlag. Source

Yang J.,Sichuan Agricultural University | Bai F.,Sichuan Agricultural University | Bai F.,Test Center for Feed Quality Supervision and Inspection Chengdu | Zhang K.,Sichuan Agricultural University | And 7 more authors.
Czech Journal of Animal Science

AFB1 is the most abundant aflatoxin in food and animal feed, generally occurring along with low levels of other aflatoxins. In this experiment, broilers were administered corn that was naturally contaminated with AFB1 and AFB2. We found that the broilers were more sensitive during the starter period and had a poor performance during the grower period. In addition, the broilers showed a significant reduction in feed intake when consuming material contaminated with 134.0 and 23.6 μg/kg of AFB 1 and AFB2, respectively. Our results also demonstrate that villus height and the ratio of villus height to crypt depth significantly decreased when the broilers were fed daily with diets contaminated with AFB 1 and AFB2. Furthermore, AFB1 residues in livers and breast muscles were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) at levels of 0.137 and 0.016 μg/kg, respectively. The AFM1 residue was also detected in livers at a level of 0.051 μg/kg but it was not detectable in breast muscles. Source

Bai X.,Sichuan Agricultural University | Bai F.,Sichuan Agricultural University | Bai F.,Test Center for Feed Quality Supervision and Inspection Chengdu | Zhang K.,Sichuan Agricultural University | And 5 more authors.
Journal of Agricultural and Food Chemistry

To investigate the deposition and elimination of melamine in hen eggs and tissues, 72 Roman laying hens were administrated with melamine at 8.6-140.9 mg per kilogram of body weight per day for 34 days. The crystals were found in one of three kidneys of hens treated with melamine at either 62.6 or 140.9 mg/kg. Furthermore, the melamine concentrations in egg, muscle, liver, kidney, stomach, duodenum, uterus, ovary, and blood plasma were determined by high-performance liquid chromatography-ultraviolet (HPLC-UV) methods. A higher dosage of melamine in the diet corresponded to higher concentrations in tissues and eggs. The concentrations of melamine in tissues were in the following ranges (μg/g): egg, 1.1-28.7; muscle, 0.4-9.3; liver, 0.5-6.9; kidney, 1.3-21.7; stomach, 0.4-7.3; duodenum, 0.3-2.8; uterus, 0.5-6.9; ovary, 0.5-9.1; and blood plasma, 0.8-7.6. When melamine was withdrawn from the diet of hens, the melamine concentration in hen tissues fell to below 2.5 μg/g by day 10 and no residues were detected in eggs or tissues at days 7 and 20, respectively. © 2010 American Chemical Society. Source

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