Determining pesticide residues in wheat flour by ultrahigh-performance liquid chromatography/quadrupole time-of-flight mass spectrometry with QuEChERS extraction

Pesticides are used to increase crop yields and preserve quality by protecting crops against pests; however, their overuse can adversely affect human health and the environment. Herein, we report the development of a multi-pesticide screening method using optimized QuEChERS coupled with liquid chromatography/quadrupole time-of-flight (QTOF) mass spectrometry for the analysis of 13 pesticides in wheat flour. Mass accuracies with errors of less than 2.4 ppm were obtained for all analysed pesticides, and the method provided satisfactory recovery and linearity. Repeatabilities of 0.3–12.7% and reproducibilities of 2.5–15.2% were observed in full-scan TOF mode. The performance of the developed full-scan TOF method was compared to that obtained in high-resolution multiple reaction monitoring (MRM-HR) mode. The limits of quantification for the full-scan TOF and MRM-HR modes ranged from 2 to 10, and 3 to 9 μg kg⁻¹, respectively. The two quantification methods exhibited high sensitivities (limit of detections: 1–3 μg kg⁻¹ in full-scan TOF, and 1–3 μg kg⁻¹ for MRM-HR mode). No pesticide residues were detected when the developed method was applied to 22 real wheat flour samples.

农药通过抵御虫害保护作物，以提升作物产量并维持品质；但过度使用农药会对人体健康与环境造成不利影响。本研究开发了一种基于优化QuEChERS前处理结合液相色谱/四极杆飞行时间（QTOF）质谱法的多农药筛查方法，用于分析小麦粉中的13种农药残留。所有被测农药的质量准确度误差均低于2.4 ppm，该方法具备良好的回收率与线性度。在全扫描飞行时间（TOF）模式下，方法的重复性相对标准偏差为0.3%~12.7%，重现性相对标准偏差为2.5%~15.2%。将所开发的全扫描TOF方法的性能与高分辨多反应监测（MRM-HR）模式下的性能进行了对比。全扫描TOF模式与MRM-HR模式的定量限分别为2~10 μg·kg⁻¹与3~9 μg·kg⁻¹。两种定量方法均具备较高灵敏度，全扫描TOF模式的检出限为1~3 μg·kg⁻¹，MRM-HR模式的检出限同样为1~3 μg·kg⁻¹。将该方法应用于22份实际小麦粉样品检测时，未检出任何农药残留。