Determination of Multiresidue Pesticides in Green Tea by Using a Modified QuEChERS Extraction and Ion-Trap Gas Chromatography/Mass Spectrometry

Abstract

The pesticide residues in exported and imported tea products must not exceed the maximum residue limits (MRLs) regulated by the import countries. Tea is a complex matrix that obfuscates the determination of pesticide residues. Many available methods for multiresidue pesticide analysis of tea are time-consuming and require many cleanup steps. The objective of this study was to develop a simple multiresidue method by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ion-trap GC/MS/MS, which can identify, confirm, and quantify pesticides in complex matrixes. A tea product was homogenized with water, and the pesticides were extracted with acetonitrile containing 1 acetic acid. The extract was subjected to centrifugation, initial cleanup with dispersive SPE (dSPE), solvent exchange, and final cleanup with dSPE. Diethyl-d10-parathion and triphenyl phosphate were used as the internal standard and surrogate, respectively. The final extract was injected into an ITQ 700 gas chromatograph/mass spectrometer. Quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient of >0.9930 for the 22 pesticides selected for the study. The recoveries of the 22 pesticides ranged from 78 to 115, except those for diazinon (130) and malathion (122), with an average RSD of 8.7. The LOD values of all of the pesticides, except for terbufos, were below the MRLs set by the European Union and Japan.

Chromatographic Determination of Pesticides in Foods and Food Products

“…The recoveries ranged from 78 to 115% except for diazinon (130%) and malathion (122%). Average RSD was 8.7%, the LOD values except for terbufos were below the MRL limit set by EU and Japan [32]. Pyrethroid residues have also been determined in tea samples.…”

Analysis of pesticide residues in tea using accelerated solvent extraction with in-cell cleanup and gas chromatography tandem mass spectrometry

“…The LOQ and LOD values obtained in this study are lower and comparable from a previous study. 11,16,17 The differences of LOD and LOQ values from component to component originate from the noise, the response factor of instruments and matrix interference. This extraction method has a good purication effect and therefore, resulting in a better detection and quantication by GC-MS/MS.…”

“…16 The combination of the dispersive SPE clean up method utilising primary secondary amine (PSA) and octadecyl (C 18 ) adsorbents could solve the purication problems and provide high recovery of the analyte. [17][18][19][20] Gas chromatography-mass spectrometry (GC-MS) has the advantages of a high separation power and identication capability and it has been widely applied in the analysis of pesticides in various food samples. Another advantage of MS/ MS is that it can be operated in selected reaction monitoring (SRM), which is benecial for the accurate quantication of the analyte.…”

“…It eliminates the confusion with similar compounds and thus obtains reliable identication and conrmation of the pesticide residues in samples. 17 To the best of our knowledge, no procedures have been reported on the use of ASE with in-cell cleanup for the purpose of simultaneous extraction of multiple classes of pesticide residues in tea. In this study, ve analytes which include organochlorine, pyrethroid or organophosphate pesticides, in 10 commercial tea samples were extracted using ASE with in-cell cleanup and analysed by GC-MS/MS.…”

Application of gas and liquid chromatography coupled to time‐of‐flight mass spectrometry in pesticides: Multiresidue analysis

“…Chromatographic techniques such as gas chromatography (GC) and liquid chromatography (LC) hyphenated with mass spectrometry (MS) using different analyzers have been commonly used. GC–MS, with various analyzers such as single quadrupole (Mladenova & Shtereva, ; Park et al, ; Yang, Wang, et al, ; Yang, Wang, et al, ), ion trap (Steiniger, Lu, Butler, Phillips, & Fintschenko, ) or triple quadrupole (QqQ) (Camino‐Sánchez et al, ; Cervera et al, ; Mladenova & Shtereva, ; Qu, Zhang, Zhu, Yang, & Aboul‐Enein, ) detection have been regularly used. Ion trap detection and QqQ analyzers are commonly utilized under tandem mass spectrometry (MS/MS) mode, contributing remarkable advantages in sensitivity and selectivity.…”