Multiresidue pesticide analysis in nutraceuticals from green tea extracts by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

A new analytical method was developed and validated for simultaneous analysis of 423 pesticides, isomers, and pesticide metabolites in nutraceutical products obtained from green tea (Camellia sinensis) extract. Response surface methodology was employed to optimize a generic extraction method. The automated extraction procedure was achieved in a simple disposable pipet extraction. Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry was used for the separation and detection of all the analytes. The method was validated by taking into consideration the guidelines specified in European SANCO/12571/2013 Guideline 2013 and Commission Decision 2002/657/EC. The extraction recoveries were in a range of 81.6-113.0%, with coefficient of variation <6.4%. The limits of decision for the analytes are in the range 0.04-4.15 μg kg−1. The detection capabilities for the analytes are in the range 0.07-6.92 μg kg−1. The 423 compounds behave dynamic in the range 0.1-200 μg kg−1 concentration, with correlation coefficient >0.99. This validated method has been successfully applied on screening of pesticide residues in one hundred and twenty-four different commercial nutraceutical products from green tea extract, and methamidophos, resmethrin, propoxur, tridemorph, ethiofencarb, flamprop isopropyl, furalaxyl, bifenthrin and fenpropathrin were detected in a few samples tested in this study.