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

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

【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。

【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.