大气压固体分析探头离子源-串联质谱法快速检测蔬菜中多种农药残留

将大气压固体分析探头离子源(ASAP)与多级质谱耦合(ASAP-MS/MS), 在无需净化或浓缩等前处理及无需色谱分离的条件下, 建立了蔬菜中13种农药残留的乙腈提取直接质谱分析方法, 单个样品检测在数分钟内即可完成. 针对常压直接分析质谱易受环境影响和上样精度差的问题, 对ASAP电离源条件如脱溶剂气温度、电晕放电电流、样品溶液组成和进样模式等进行了优化; 采用多反应监测扫描(MRM), 通过产物离子丰度比进行定性, 用内标标准曲线法定量; 对韭菜、油菜和芹菜3种基质进行了考察, 结果表明存在明显的基质效应. 本方法在5.0~500 μg/L浓度范围内的线性相关系数均高于0.995, 检出限为0.04~0.89 μg/kg, 精密度(RSD, n=7)为5.1%~13.0%. 超高效液相色谱-电喷雾串联质谱法对实际样品的检测结果与ASAP-MS/MS的检测结果一致. 该方法分析速度快, 灵敏度高, 无需有机溶剂且结果可靠, 可应用于大批量农药残留的筛查和应急监测任务.

Rapid Quantification of 13 Pesticides in Vegetables by Atmospheric-Pressure Solids Analysis Probe(ASAP) Coupled to Tandem Mass Spectrometry

A rapid direct-analysis method using atmospheric pressure solids analysis probe coupled to tandem mass spectrometry(ASAP-MS/MS) was established for the detection of thirteen commonly used multi-class pesticides in vegetables, without cleanup, concentration or chromatographic separation, and a single run can be done in minutes. To compensate for the poor precision and instability in ambient ionization technique, ASAP source parameters of the corona discharge, desolvation gas temperature, sample solvent and sample-load mode were optimized. The target compound was identified by product ion abundance ratios in multiple reaction monitoring(MRM)mode and semi-quantified through internal standard calibration curves. The matrix effects of celery, leek and rape were analyzed, and had apparent influences. Under the optimal conditions, the linear range was 5.0—500 μg/L with a coefficient of above 0.995. The limit of quantification(LODs) of analytes were 0.04—0.89 μg/kg, with a precision of 5.1%—13.0%(n=7). The real sample determination shows that the results by ASAP-MS/MS were in accordance with those obtained by ultra performance liquid chromatography coupled to tandem mass spectrometry(UPLC-MS/MS). The proposed ASAP-MS/MS technique can be a powerful tool due to its convenience, rapid, reliable, low-cost and eco-friendly for pesticide screening and emergency monitoring.