PMID- 22882823 OWN - NLM STAT- MEDLINE DCOM- 20121211 LR - 20191210 IS - 1873-4324 (Electronic) IS - 0003-2670 (Linking) VI - 743 DP - 2012 Sep 19 TI - Streamlining sample preparation and gas chromatography-tandem mass spectrometry analysis of multiple pesticide residues in tea. PG - 51-60 LID - 10.1016/j.aca.2012.06.051 [doi] AB - In this work, a new rapid method for the determination of 135 pesticide residues in green and black dry tea leaves and stalks employing gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) with a triple quadrupole was developed and validated. A substantial simplification of sample processing prior to the quantification step was achieved: after addition of water to a homogenised sample, transfer of analytes into an acetonitrile layer was aided by the addition of inorganic salts. Bulk co-extracts, contained in the crude organic extract obtained by partition, were subsequently removed by liquid-liquid extraction using hexane with the assistance of added 20% (w/w) aqueous NaCl solution. The importance of matrix hydration prior to the extraction for achieving good recoveries was demonstrated on tea samples with incurred pesticide residues. For most of the analytes, recoveries in the acceptable range of 70-120% and repeatabilities (relative standard deviations, RSDs)