GC-MS/MS Analysis of Pesticide Residues in Green Tea Extracted by QuEChERS with Acetonitrile as Final Solvent

QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) is a well known approach used for the extraction and clean-up of pesticide residues in various matrices. Typically, the final extraction solvent is acetonitrile. Direct injection of acetonitrile extracts can be problematic in GC-MS compared to LC-MS because of poor focusing of chromatographic peaks due to the high polarity of acetonitrile, limitations on injection volumes due to the high expansion coefficient of acetonitrile and contamination of the system by matrix co-extractives [1]. Here we present a simple and robust analytical method which employs low volume splitless injections of acetonitrile sample extracts and the selectivity of the Thermo Scientific™ TSQ™ 8000 triple quadrupole GC-MS/MS instrument. With this approach, pesticide target reporting limits of <0.01 mg/kg can be easily achieved. This also overcomes the problems associated with the thermal expansion of acetonitrile and reduces the amount of matrix injected.