液相微萃取——高效液相色谱法测定水稻中的吡虫啉

研究了基于中空纤维的动态三相液相微萃取(LPME),并首次将其应用到稻谷、稻叶、田水和土壤中吡虫啉农药残留的快速分离富集。实验采用磷酸二氢钾作接受液,以高效液相色谱(HPLC)为检测手段,系统地优化了LPME技术的有机溶剂、搅拌速率和萃取时间等条件。最佳色谱条件为:SB-Phenyl C18(250mm×4.6mm,5μm)液相色谱柱,以甲醇–水–三乙胺(80∶20∶1,v/v)为流动相,流速0.8mL/min,270nm波长下检测。得到方法的线性范围0.001～10μg/mL,最低检出限为1ng/mL,加标回收率92.50%～110%,富集倍数19.2倍。结果表明该方法是一种简单、快速、准确、环境友好的农药残留检测方法。

Determination of Imidacloprid in Rice Based on Three-phase Hollow Fiber Liquid Phase Micro-extraction-High Performance Liquid Chromatography

A novel method for fast separate and enrichment imidacloprid in paddy, leaf, water and soil was established by using high performance liquid chromatography （HPLC） coupled with a three-phase hollow fiber based liquid phase micro-extraction （TP-HF-LPME） technique for sample preparation. Parameters related to TP-HF-LPME （organic solvent, stirring speed, pH of donor and acceptor phase, extraction time） were also optimized experimentally. The method was developed using an SB-Phenyl C18（250mm×4.6mm,5μm） column, methanol - water - triethylamine （80：20：1, v/v） as mobile phase and detection at 270 nm. It has been demonstrated to be a very fast, effective and virtually ‘green＇ sample preparation technique, which provided a good linear range （0.001 to 10μg/mL） with r^2=0.9997 （standard working curves）, a low detection limit （1ng/mL, S/N =3） and the addition recovery was obtained in the range of 92.50% to 110%. The proposed method integrates extraction, enrichment and clean-up into a single step, which is a simple, effective, veracious and environmental friendly method for detecting pesticide residue.