Rapid Analysis of Residues of 186 Pesticides in Hawk Tea Using Modified QuEChERS Coupled with Gas Chromatography Tandem Mass Spectrometry

Abstract

In this work, the QuEChERS method was modified and evaluated for the determination of 186 pesticides from caffeine-free and fatty hawk tea prior to their gas chromatography tandem mass spectrometry analysis for the first time. The results showed that the combination of MgSO4 + PSA + MWCNTs plus EMR-Lipid provided the lowest matrix effect and best recovery; 117 of 186 pesticides manifested weak matrix effects. Thus, for accurate quantification, it is necessary to use matrix-matched calibration curves to compensate for the matrix effect. At the spiked level of 0.1 mg/kg, the average recoveries of 184 pesticides were in the range of 70–120% and the RSDs were 0.3–14.4% by the modified method. Good linearity was shown for 186 analytes at concentration of 0.01 mg/L~0.4 mg/L, and the correlation coefficients exceeded 0.99 for 182 pesticides. The detection limits of 186 pesticides by the modified QuEChERS method were 0.001–0.02 mg/kg, and the limits of quantification (LOQ) were 0.005 mg/kg~0.05 mg/kg. The necessity of solvent exchange is also explained in this work. The successful application of the modified QuEChERS in real samples proved that this method could be one of the routine options for analysis of herbal tea.

Multivariate optimization and validation of 200 pesticide residues in the banana matrix by GC-MS/MS

“…However, it is significant to note that the authors validated and estimated their results using 1200 mg MgSO 4 , 400 mg PSA, and 200 mg MWCNTs which is much higher than the usage reported in the current study. 29 Hiago de O. Gomes et al analyzed three compounds, namely azoxystrobin, difenoconazole, and propiconazole, using a modified QuEChERS-dSPE-GC/MS method. Results obtained indicated LOD values of 0.018, 0.066, and 0.007, LOQ values of 0.054, 0.199, and 0.022, and r 2 values of 0.9985, 0.9966, and 0.9997, respectively.…”