气相色谱-四极杆飞行时间质谱准确鉴定常见水果蔬菜中的农药残留

建立了一种新型农药多残留检测方法。采用气相色谱-四极杆飞行时间质谱（GC-QTOF MS）结合Carbon NH₂柱固相萃取净化可对不同类别的152种农药残留进行准确的鉴定。一级（MS¹）精确质量数据库评价3~5个特征离子，以3个及以上特征离子检出且离子丰度比（Q/q_i）合适作为一级质谱定性依据。对部分特征离子数不足及特征离子检出情况不符合条件的农药进行二级（MS²）确证，应用二级谱图库检索及镜像结果对比分析实现疑似农药确证。本文对梨、甘蓝、番茄3种代表性果蔬在5.0和10.0 μg/kg 2个添加水平的152种农药进行测定，回收率在70%~120%范围的比例分别为甘蓝91.45 %、94.08%，番茄88.20%、88.80%，梨86.84%、92.10%。本方法为常见果蔬中农药残留的准确判断提供了可靠依据，扩大了分析范围。

Identification of pesticide residues in common fruits and vegetables by gas chromatography-quadrupole time-of-flight mass spectrometry

A new screening method was developed for the determination of 152 pesticide multi-residues in different chemical species with a Carbon NH₂ column using solid-phase extraction (SPE) coupled with gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF MS). In the first stage (MS¹) accurate mass database, up to three-five ions of the pesticides were monitored. The presence of at least three ions and the accomplishment of the intensity ratio (Q/q_i) within the established tolerances were used as the confirmation of intensity criteria. The pesticides which have less characteristic ions or the peaks of the characteristic ions detected were up the tolerance were determined in the second stage (MS²) and the spectral difference was evaluated using MS² library for the identified. Cabbage, tomato, pear were selected as typical fruits and vegetables to spike and detected all the 152 pesticides at two concentration levels of 5.0 and 10.0 μg/kg. The recoveries in the range of 70%-120% at two concentration levels were 91.45% and 94.08% for cabbage, 88.20% and 88.80% for tomato, 86.84% and 92.10% for pear respectively. Using the established 152 pesticide MS² library some suspected pesticides were identified, and at the same time the analysis scope was expanded.