LIF-HPCE法检测食品中的黄曲霉毒素B1

采用自行设计搭建的激光诱导荧光(LIF)- 高效毛细管电泳(HPCE)检测平台,建立LIF-HPCE 法对食品中的黄曲霉毒素B1(AFB1)进行高灵敏度检测。AFB1 在胶束电动毛细管电泳(MECC)模式下分离,LIF 检测,375nm 激光进行激发,检测波长440nm,操作电压15kV,电流104μA。AFB1 在0.5～50μg/kg 浓度范围内线性关系良好,r ＝ 0.9994;最低检出质量1.7 × 10-13g(S/N ＝ 3),最低定量限5.6 × 10-13g(S/N ＝ 10),方法精密度和重复性的相对标准偏差为5% 左右。测定食品中粮油等食品样品,加标回收率为84.1%～96.1%。所建立的方法无需进行衍生反应和荧光标记,快速灵敏,绿色环保,10min 左右完成分析,适用于食品中黄曲霉毒素的高灵敏度检测。     

Development of high‐performance liquid chromatography and non‐aqueous capillary electrophoresis methods for the determination of fenoxycarb residues in wheat samples

BACKGROUND: Practical methods for the analysis of fenoxycarb residues in wheat samples were developed using high‐performance liquid chromatography (HPLC) and non‐aqueous capillary electrophoresis (NACE). RESULTS: Fenoxycarb residues in wheat were extracted with acetone by ultrasonication, followed by a clean‐up procedure with liquid–liquid extraction with 5% NaCl/dichloromethane. The HPLC was developed using C18 as column, MeOH/water (6:4, v/v) as the mobile phase and 199 nm as the detection wavelength. The optimal NACE condition was established with the running buffer of 20.0 mmol L^?1 NH₄Ac in 95% MeOH (pH* 9.0), and the applied voltage of 30 kV over a capillary of 50 µm i.d. × 48.5 cm × 40 cm effective length. Both methods gave the relatively lower limits of detection (0.008 mg kg^?1 for HPLC and 0.024 mg kg^?1 for NACE) and the higher recoveries (>85.0%). They were successfully applied to the determination of fenoxycarb in wheat samples. CONCLUSION: The results showed that the fenoxycarb residue gradually reduced to trace amounts after about 3 years, which implied that the pharmacological actions of fenoxycarb could last for about 3 years. Meanwhile, more effort should be made to control and reduce fenoxycarb residues because of its potential health risks to consumers. Copyright © 2007 Society of Chemical Industry     

Analysis of tea catechins in vegetable oils by high‐performance liquid chromatography combined with liquid–liquid extraction

In this study, a method was developed for the determination of various tea catechins in vegetable oils. Firstly, vegetable oils including tea seed oil, sunflower seed oil and soya bean oil were extracted by methanol/water (40:60, v/v), and then, a high‐performance liquid chromatography (HPLC) method was developed for the simultaneous determination of GA, caffeine, EGC, EGCG, EC, ECG, GC, GCG, C and CG. For the compounds detected in tested vegetable oils, LODs were in the range of 0.05–1.65 ng, both intraday and interday relative standard deviations (RSDs) were <5.0%, and the recovery rates were in the range of 96.2–100.5% with RSD <3.7%. The results showed in vegetable oils which declared to had added tea catechins in, the concentrations of tea catechins were less than that showed in package label, and the content of EGCG was the highest in all samples. Therefore, the advancement made in our study will facilitate studies of tea catechins in oil industry.