Simultaneous Determination of Seven Pesticides and Metabolite Residues in Litchi and Longan through High-Performance Liquid Chromatography-Tandem Mass Spectrometry with Modified QuEChERS

This study established a QuEChERS high-performance liquid chromatography/tandem triple-quadrupole mass spectrometry method for determining azoxystrobin, pyraclostrobin, picoxystrobin, difenoconazole, chlorantraniliprole, imidacloprid, and cyantraniliprole and its metabolite (IN-J9Z38) in litchi and longan, and applied this method to the real samples. The residues in samples were extracted with acetonitrile and purified with nano-ZrO2, C-18, and PSA. The samples were then detected with multireactive ion monitoring and electrospray ionization in the positive ion mode and quantified using the external matrix-matched standard method. The results showed good linearities for the eight analytes in the range of 1-100 mu g/L, with correlation coefficients (r(2)) of >0.99. The limit of quantification was 1-10 mu g/kg, and the limit of detection was 0.3-3 mu g/kg. Average recovery from litchi and longan was 81-99%, with the relative standard deviation of 3.5-8.4% at fortified concentrations of 1, 10, and 100 mu g/kg. The developed method is simple, rapid, efficient, and sensitive. It allowed the rapid screening, monitoring, and confirming of the aforementioned seven pesticides and a metabolite in litchi and longan.

Automated summary

A QuEChERS high-performance liquid chromatography/tandem triple-quadrupole mass spectrometry method was established for the determination of several pesticides and their metabolite in litchi and longan. The developed method is simple, rapid, efficient, and sensitive, allowing for wide application in screening and monitoring of pesticide residues in agricultural products.