UPLC-MS/MS法测定水稻及其环境中的草酮和苯噻酰草胺残留量

Determination of Oxadiazon and Mefenacet Residues in Rice and Its Environment by UPLC-MS/MS

[目的]建立测定稻田水、土壤、植株、水稻中草酮和苯噻酰草胺的UPLC-MS/MS测定方法。[方法]水样以乙酸乙酯为萃取溶剂,液液分配净化;土壤样品用硅藻土混合分散,以丙酮-二氯甲烷(体积比1∶1)为萃取剂,经ASE萃取富集,N-丙基乙二胺(PSA)、C_(18)、无水Mg SO_4净化;植株及水稻样品经乙腈提取,Carbon/NH_2固相萃取柱净化。用C_(18)色谱柱分离,以0.1%甲酸水溶液和0.1%甲酸甲醇溶液作为流动相进行梯度洗脱,电喷雾正离子模式(ESI^+)电离,多反应监测模式(MRM)检测,基质匹配标准溶液外标法定量。[结果]2种农药在0.5~100μg/L范围内线性关系良好(r>0.999),方法的检出限在0.08~0.4μg/kg之间,定量限(S/N=10)在0.2~1μg/kg之间,添加水平为1、2、50μg/kg时,2种农药的回收率在75.06%~99.95%之间,相对标准偏差在2.05%~9.92%之间。[结论]该方法灵敏度高、定量准确,用基质配制标准溶液能够有效准确地校正基质效应,可用于环境中草酮和苯噻酰草胺残留量的检测。

[Aims]The UPLC-MS/MS method for determination of oxadiazon and mefenacet in paddy water,soil,rice straw and rice was established.[Methods]The water sample was extracted with ethyl acetate as solvent and purified by liquid-liquid distribution.The soil samples were mixed and dispersed with diatomite,the mixture of acetone and carrene（1∶1,by vol）was used as the extractant,which was enriched by ASE,dehydrated with anhydrous magnesium sulfateand cleaned up by primary secondary amine（PSA）and octadecyl bonded silica gel（C18）;the rice straw and rice samples were extracted with acetonitrile and purified with Carbon/NH2solid phase extraction.The target samples were separated by C18column with gradient elution using 0.1%formic acid aqueous solution and 0.1%formic acid methanol solution as mobile phases.The compounds were ionized under electrospray positive ion mode（ESI^＋）,detected under multiple reaction monitoring mode（MRM）,and quantified by matrix matching standard solution external standard method.[Results]The linear range of the 2 pesticides ranged from 0.5 to 100μg/L with the correlation coeffiients of more than0.999.The limits of detection of the method were in the range of 0.08 to 0.4μg/kg and the limits of quantitation（S/N=10）were in the range of 0.2 to 1.0μg/kg.When the addition level was 1,2 and 50μg/kg,the average recoveries ranged from 75.06 to 99.95%and the relative standard deviations（RSD）ranged from 2.05 to 9.92%.[Conclusions]The method has high sensitivity and accurate quantification,preparation of standard solution with matrix can correct matrix effect effectively and accurately,it can be used for the determination of oxadiazon and mefenacet residues inenvironment.