Determination of 8 Aniline Herbicides in Oil Crops by Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was developed for the simultaneous determination of 8 aniline herbicides in oil crops by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). The samples were ultrasonically extracted with acetonitrile,and then purified with N-propyl ethylenediamine(PSA)and anhydrous magnesium sulfate. The target compounds were separated on a ZORBAX Eclipse Plus C₁₈column(2.1 mm×100 mm,1.8 μm)by gradient elution using methanol(containing 1% acetonitrile)and 5 mmol/L ammonium acetate solution(containing 0.1% formic acid)as mobile phase at a flow rate of 0.3 mL/min. Qualification was achieved by positive electro-spray ionization using multiple reaction monitoring(MRM),and the external standard method was used for quantitation. The calibration curves for 8 aniline herbicides were linear in their corresponding range(2.0~200 μg/L for pendimethalin,butralin and metosulam,5.0~200 μg/L for isopropalin,0.5~200 μg/L for nitralin,diethatyl ethyl,chlorpropham and chlorbufam)with their correlation coefficients(r)all above 0.999. The recoveries for 8 aniline herbicides at three different spiked levels were in the range of 69.5%~97.5% with relative standard deviations(RSD)of 0.5%~9.5%(n=5). The limits of detection(S/N=3)and quantitation(S/N=10)of the method were 0.07~1.20 and 0.23~4.00 μg/kg,respectively. Owing to high efficiency and sensitivity,the method was suitable for rapid and simultaneous analysis of aniline herbicides in oil crops.