Effectiveness of pressurized liquid extraction and solvent extraction for the simultaneous quantification of 14 pesticide residues in green tea using GC

Abstract

A simultaneous multiresidue method to determine 14 different pesticides, namely: flufenoxuron, fenitrothion, chlorfluazuron, chlorpyrifos, hexythiazox, methidathion, chlorfenapyr, tebuconazole, EPN, bifenthrin, cyhalothrin, spirodiclofen, difenoconazole, and azoxystrobin in green tea using pressurized liquid extraction (PLE) is described and compared with that of liquid-liquid extraction (LLE). For PLE, the extraction conditions were not optimized. Rather they were selected based upon previous successful investigations published by our laboratory. Analysis was performed by GC with electron capture detector (GC-ECD), and the pesticide identity of the positive samples was confirmed by GC-MS in a selected ion-monitoring (SIM) mode. Calibration curves showed an excellent linearity for concentrations ranging from 0.006 to 36.049 ppm, with r(2) >0.995. Green tea spiked at each of the two fortification levels, yielded average recoveries in the range of 87-112% and 71-109% for PLE and LLE, respectively. Precision values, expressed as RSDs, were below 6% at various spiking levels. With respect to the existing procedures, both methods gave LOQs that were lower than the maximum residue limits (MRLs) established by the Korea Food and Drug Administration (KFDA). Both methods have been successfully applied to the analysis of real samples, and bifenthrin was the only pesticide residue quantified in incurred green tea samples, with concentrations ranging from 0.093 ppm (LLE) to 0.1 ppm (PLE). These concentration levels were relatively low compared to KFDA-MRL (0.3 ppm). According to the validation data and performance characteristics, both methods are appropriate for multiresidue analysis of pesticide residues in green tea. PLE methodology showed superiority in recoveries of some pesticides, acceptable accuracy and precision while minimizing environmental concerns, time, and labor, and can be applied in routine analytical laboratories.

Simultaneous determination of pyrethroids from pesticide residues in porcine muscle and pasteurized milk using GC

“…Furthermore, the analytical methods used must be capable of measuring the residues at very low levels, as well as providing unambiguous evidence to confirm both the identity and the magnitude of any residues detected [4]. In recent years, new extraction techniques for the extraction of pesticide residues from food commodities have emerged including supercritical fluid extraction (SFE) [5,6], ASE [7,8], solid-phase microextraction (SPME) [9,10], and matrix solid-phase dispersion (MSPD) [11,12]. However, a LLE technique that uses organic solvents such as acetone, hexane, and ethyl acetate [13] is still the preferred method.…”

Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

“…Used for identification of a range of compounds, including Donovan et al, 1999;Kanrar et al , 2010;Steiniger et al , 2010;Xu et al, 2010;Tsumura et al 1994;Li et al 2004;Huang and Huang 2006;Cho et al, 2008;Schurek et al, 2008;Mo et al, 2009;Moinfar and Hosseini, 2009; Pesticides, Essential oils, volatile compounds, metabolic fingerprinting, acrylamides Hu, Liang et al, 2010;Clark and Bunch, 1997;Bilia, Flamini et al, 2002;Mizukami, Kohata et al, 2006;Pongsuwan, Fukusaki et al, 2007;Rawat, Gulati et al, 2007;Pongsuwan, Bamba et al, 2008;Ciecierska and Obiedzinski 2009; Rechner et al, 2002;Guillarme, Casetta et al , 2010;Bramati et al, 2002;Pelillo et al, 2002;Bramati et al, 2003;Pelillo et al, 2004;Yamauchi et al, 2008;Cordero et al, 2009;Lv et al, 2009 HPLC-ECD Selective determination of polyphenols, including catechins Sano et al, 2001;Novak et al, 2010 HPLC-FD Determination of (+)-catechin in tea Ho et al, 1995HPLC-MS Cathechins, Flavonoids, polyphenols Kuhnert, Clifford et al, 2010Kiehne and Engelhardt, 1996;Kiehne, Lakenbrink et al, 1997;…”

An quantificational method for 51 pesticide residues determination in Pu'er tea by LC-MS/MS

“…So far Various determination strategies and techniques for pesticides detection in tea have been published, including GC-electron capture detection (GC-ECD), GC-flame photometric detection (GC-FPD), GC with a flame ionization detector (GC-FID), HPLC-fluorescence detector (HPLC-FLD),GC-MS and LC-MS/MS etc [5][6][7][8][9][10][11][12][13][14][15][16] . Among the all the methods,Conventional liquid Chromatography high effective separation function coupled with MS a validated method to conformation compound is becoming a new routine pesticide residue determination programs, which exhibits higher sensitivity and specificity [17][18] .…”