Comparison of three multiresidue methods to analyse pesticides in green tea with liquid and gas chromatography/tandem mass spectrometry

Abstract

The aim of the present work was to compare and choose the best method to extract pesticide residues from green tea. Three different multiresidue methods were tested on blank green tea samples fortified with 86 pesticides (insecticides, fungicides and herbicides) at the 100 μg kg(-1) level - modified QuEChERS (in order to limit the amount of coextractives, MgSO(4) was replaced with calcium chloride in the clean-up step); ethyl acetate extraction (not SweEt) and miniLuke. Due to matrix complexity, samples were diluted five times. The extracts were analysed by GC-MS/MS and LC-MS/MS. During the experiment recoveries, the precision and influence of coextracted compounds were compared. The study carried out on the three methods showed that the best results were achieved using QuEChERS. In terms of recoveries, QuEChERS showed the highest performance - successfully analysing 75 compounds (87% of the total number) with recoveries from 70 to 120% - whereas the miniLuke and ethyl acetate methods had 54 (63% of the total number) and 31 (36% of the total number), respectively. In addition, QuEChERS extracts contained the least amount of co-extracted matrix components. All three methods provided very good precision.

Miniaturisation and optimisation of the Dutch mini-Luke extraction method for implementation in the routine multi-residue analysis of pesticides in fruits and vegetables

“…Another critical point to check was the salts added to induce a water-acetone partitioning, which was investigated by Schenck, Callery, Gannett, Dast, and Lehotay (2002). Over recent years, only few specific papers about the mini-Luke method have been published (Díez, Traag, Zomer, Marinero, & Atienza, 2006;Hiemstra & de Kok, 2007 Rajski et al, 2013), even though this method has been widely used in routine analysis of vegetable crops and most of them compared the results obtained by mini-Luke method with other multi-residue methods, obtaining in the majority of the cases very similar results.…”

Application of QuEChERS based method for the determination of pesticides in nutraceutical products (Camellia sinensis) by liquid chromatography coupled to triple quadrupole tandem mass spectrometry

“…Concerning sample treatment, in the case of green tea, QuEChERS (acronym of quick, easy, cheap, effective, rugged and safe) is the extraction procedure most widely used by the revised literature (Chen et al, 2010;Kanrar, Mandal, & Bhattacharyya, 2010;Kittlaus, Schimanke, Kempe, & Speer, 2013;Lozano et al, 2012;Rajski et al, 2013;Zhao, Wang, Jiang, Zhang, & Pan, 2012). Other sample treatments used were solid phase extraction (SPE) (Gupta & Shanker, 2008;Huang et al, 2009;Inoue et al, 2013;Lu et al, 2010;Zhang et al, 2010), and solid phase microextraction (SPME) (Ishizaki, Sito, & Kataoka, 2010).…”

Determination of pesticide multi-residues in green tea using a modified QuEChERS extraction and liquid chromatography tandem mass spectrometry technique

“…To get the moisture content of around 80%, the water to sample ratio was set at 5:1 (w/w). The sample then was left for 30 min to ensure a complete hydration without further investigation of the amount of water and the soaking duration (STEINIGER et al, 2010;CHEN et al, 2011;RAJSKI et al, 2013).…”

“…Pesticide multi-class, multi-residue determination relies on the QuEChERS extraction combined to LC-MS/MS and/or GC-MS(/MS) instrumentation could be used to identify a few hundreds of pesticides in one single test (LEHOTAY et al, 2005;NGUYEN et al, 2010;DAI et al, 2011). Its applications have also spread to other matrices like tea, herb, rice, and other grains (STEINIGER et al, 2010;CHEN et al, 2011;FAN et al 2013;GUAN et al, 2013;RAJSKI et al, 2013).…”

“…These methods, however, are time-and labour-consuming and require large volumes of various kinds of solvents. Recently, QuEChERS method has been applied to extract pesticides from tea (STEINIGER et al, 2010;CHEN et al, 2011;LOZANO et al, 2012;GUAN et al, 2013;RAJSKI et al, 2013;SHOEIBI et al, 2013). To deal with the matrix effect problem, many techniques have been tried including a sample dilution, matrix calibration, various types and amounts of sorbent addition, or SPE cleanup (STAHNKE et al, 2012;FAN et al, 2013;GUAN et al, 2013;RAJSKI et al, 2013;WANG et al, 2013).…”