在线柱后衍生-荧光检测-高效液相色谱法测定果蔬中残留氨基甲酸酯农药

HPLC Determination of Residual Carbamate Pesticides in Fruits and Vegetables with On-line Post-column Derivatization and Fluorescence Detection

提出了具有在线柱后衍生流路及荧光检测器的高效液相色谱法测定了果蔬中6种氨基甲酸酯类农药。果蔬样品经匀浆后用乙腈萃取，经固相萃取柱纯化。用甲醇及二氯甲烷（1＋99）混合溶剂作淋洗剂，淋出液经氮吹蒸干后用甲醇溶解，所得溶液供高效液相色谱分析。采用Carba-mate Analysis柱（3．9mm×150mm，5μm）作为固定相，并用不同比例配制的甲醇和水的溶液作为流动相进行梯度淋洗。在线柱后衍生化系在-反应器中进行，0．05mol．L^-1氢氧化钠溶液及衍生化试剂邻苯二甲醛溶液均以0．5mL·min^-1速率引入于反应器中。采用339nm及445nm分别作为荧光检测的激发波长和发射波长，测得6种农药的线性范围均在0．01～2．5mg·L^-1之间，其检出限（3S／N）在0．5～3．0gg·kg^-1之间。用标准加入法测得方法的回收率在86．4％～103．0％之间。

Six residual carbamate pesticides in fruits and vegetables were determined by HPLC with orrline post-column derivatization and fluorescence detection. The sample was pounded, homogenized and extracted with acetonitrile, and purified by SPE column. The mixed solvent of methanol and dichloromethane（1＋99） was used as eluant, and the eluates were collected and evaporated to dryness by N2-blowing. The residue was taken up with methanol and used for HPLC analysis. The Carbamate Analysis column （3. 9 mm× 150 mm, 5μm） was used as stationary phase and mixtures of methanol and H2O with various ratios were used as mobile phase in gradient elution. On-line post-column derivatization was carried out in the reactor into which 0.05 mol · L^-1 NaOH solution and derivatizing agent, OPA solution were introduced at a flow-rate of 0. 5 mL ·min^-1. Fluorescence detection was made at wavelengths of 339 um （λex） and 445 nm （λcm）. Ranges of linearity for the 6 pesticides were found between 0. 01--2. 5 mg· L^-1, with detection limits （3S/N） in the range of 0. 5--3. 0ug·kg^-1. Results of recovery test obtained were in the range of 86. 4%-103. 0%.