基于分散固相萃取-超高效液相色谱串联质谱法同时测定蔬菜中多种除草剂残留的方法

【目的】研究吸附填料不同添加量对除草剂回收率的影响,以建立蔬菜中24种除草剂残留的分散固相萃取-超高效液相色谱串联质谱(UPLC-MS/MS)检测方法。【方法】蔬菜样品加入乙腈振荡提取,将净化填料N-丙基乙二胺(PSA)(不同添加量0.05 g、0.10 g、0.20 g)加入提取液中净化。采用UPLC-MS/MS测定,对液相色谱柱、流动相条件和质谱条件(锥孔电压、碰撞能量)进行优化,电喷雾电离,多反应监测模式检测。【结果】以0.1%的甲酸水-乙腈为流动相进行梯度洗脱,各化合物峰形尖锐,灵敏度高,UPLC-MS/MS上机10 min内完成了24种除草剂的检测。添加0.10 g和0.20 g PSA时,三氟羧草醚、2,4-滴、唑嘧磺草胺、噻吩磺隆、苯磺隆、氯嘧磺隆6种除草剂回收率明显降低;其余除草剂随着PSA添加量的增加回收率没有明显的变化,在75.5%—114.7%之间;吸附填料PSA添加量为0.05 g时,24种除草剂回收率为65.6%—114.7%。24种除草剂在1.0—250μg·L~(-1)质量浓度范围内线性关系良好,相关系数为0.9946—0.9998。蔬菜中24种除草剂的方法检出限在1.2—160.8μg·kg~(-1),定量限在4.0—536.0μg·kg~(-1),可以满足定量分析的要求。在空白蔬菜样品中添加50、100、200μg·kg~(-1)3个质量分数的24种除草剂的混合标准溶液,24种除草剂的回收率在66.5%—116%,相对标准偏差在2.3%—9.7%。采用建立的测定方法,对38份蔬菜样本进行检测发现,所有蔬菜样品中仅检出阿特拉津残留,检出率为57.9%,检出范围为未检出—0.84μg·kg~(-1),其余23种除草剂均未检出。【结论】该方法简便、快速、节省溶剂、灵敏度高,可用于大批量蔬菜中除草剂残留快速检测。

Simultaneous Determination of Multi Herbicides Residues in Vegetables by Dispersive Solid Phase Extraction and Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

【Objective】 To study the purification efficiency of different amount of absorption on the recovery of the herbicides, the ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with dispersive solid phase extraction method was developed for the determination of 24 herbicides in vegetables．【Method】 The vegetable samples were extracted with acetonitrile and purified by primary-secondary amine (PSA) with different dosage of 0.05 g, 0.10 g and 0.20 g. UPLC-MS/MS method was performed with electrospray ionization (ESI) source under the multiple reaction monitoring (MRM) mode．【Result】0.1% formic acid water-acetonitrile was chosen as mobile phase in gradient elution, and the peaks of all the compounds were sharp with high sensitivity under this conditions. 24 kinds of herbicides were detected by UPLC-MS/MS within 10 min. Adding 0.10 g and 0.20 g PSA, the recovery rate of acifluorfen, 2,4-Dicholrophenoxyacetic acid, flumetsulam, thifensulfuron methyl, tribenuron methyl, and chlorimuron ethyl was decreased significantly, and the rest of the herbicides recovery did not change significantly, ranging from 75.5% to 114.7%. When adding 0.05 g PSA, 24 herbicides recovery rate was 65.6%-114.7%. Standards concentration ranged from 1.0 µg·L^-1 to 250 µg·L^-1 had a good linear relationship, and the correlation coefficient was 0.9946-0.9998. Limits of detection of 24 herbicides in vegetables ranged from 1.2 to 160.8 µg·kg^-1, and limit of quantitative between 4.0 and 536.0 µg·kg^-1, which can satisfy the requirement of quantitative analysis. The mixed standard solution of 24 herbicides were spiked in the blank vegetable samples at three levels 50, 100, 200 µg·kg^-1, and the recovery of 24 kinds of herbicides at the rate of 66.5%-116%, the relative standard deviation between 2.3%-9.7%, which can meet the requirements. Using the established determination method, 38 vegetable samples were detected, and only atrazine was detected in all vegetable samples with the detection rate of 57.9% and the detection range from not detected to 0.84 µg·kg^-1. The other remaining 23 kinds of herbicides were not detected.【Conclusion】The UPLC-MS/MS method is simple, rapid, solvent saving and sensitive, which is suitable for the determination of herbicides in a large number of vegetable samples.