QuEChERS-气相色谱法测定土壤中砜吡草唑残留量

Determination of pyroxasulfone residue in soil by QuEChERS-gas chromatography

[目的]为砜吡草唑的安全高效应用提供技术支撑,拟采用QuEChERS-气相色谱法,建立简便、快速、准确测定砜吡草唑在土壤中残留的分析方法。[方法]土壤中砜吡草唑经乙腈提取,PSA净化,离心后取上清液氮吹至干,加入正己烷-丙酮(体积比90∶10)复溶、过滤后经气相色谱μECD检测器检测,以外标法定量。通过对色谱条件、前处理方法优化,选择最合适的检测方法。[结果]在0.002~1 mg/L范围内,线性关系良好,相关系数(r)大于0.99。0.01~1 mg/kg添加水平下,砜吡草唑在空白土壤样品中的平均加标回收率为97.0%~102.0%,相对标准偏差为1.1%~6.8%。该方法定量限(LOQ)为0.01 mg/kg,最小检出限0.003 mg/kg。[结论]该检测分析方法操作流程简便、检测速度快、灵敏度高、重现性好,适用于土壤中砜吡草唑残留量的快速测定。

[Aims]In order to provide a technical support for the safe and efficient application of pyroxasulfone,Quechers-gas chromatography is proposed to establish a simple,rapid and accurate analysis method for the determination of sulfoxyprazole residues in soil.[Methods]The pyroxasulfone in soil was extracted by acetonitrile,purified by PSA,and centrifuged.The supernatant was nitrogen-blown to dryness,dissolved with n-hexane+acetone(90∶10,by vol),filtered and detected by gas chromatography with aμECD detector,and quantified by external standard method.The most suitable detection method was selected by optimizing the chromatographic conditions and pretreatment methods.[Results]In the range of 0.002-1 mg/L,the linearity was good and the correlation coefficient(r)was greater than 0.99.The average recoveries of pyroxasulfone in soil at the spiked levels of 0.01-1 mg/kg in the blank samples were in the range of 97.0%-102.0%.The relative standard deviations ranged from 1.1%to 6.8%.The limit of quantification(LOQ)was 0.01 mg/kg,and the minimum limit of detection(LOD)was 0.003 mg/kg.[Conclusions]The analytical method is straightforward,rapid,sensitive and highly reproducible,making it ideally suited for the quick detection of pyroxasulfone residues in soil.