Submitted to: Journal of Chromatography A
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2009
Publication Date: 1/22/2010
Citation: Lehotay, S.J., Son, K.A., Kwon, H., Koesukwiwat, U., Fu, W., Mastovska, K., Hoh, E. 2010. Comparison of QuEChERS sample preparation methods for the analysis of pesticide residues in fruits and vegetables. Journal of Chromatography A. 1217:2548-2560. Interpretive Summary: Pesticide residue analysis must be done for a variety of reasons, and the most effective and efficient analytical method should be used to achieve the best results in the fastest and most cost-effective manner. The “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) approach to pesticide residue analysis meets the needs of the application, but the concept is so flexible that three different versions are commonly used by different laboratories. This paper describes a study that is designed to answer the question, “Which version of QuEChERS is best?” The results show that all three QuEChERS methods perform very well, but AOAC Official Method 2007.01 was found to give better overall results. It is also somewhat more practical than the European Standard Method EN 15662, which uses more reagents and takes a bit longer. Based on this study, more labs are expected to use the AOAC official version of QuEChERS, and it will simplify the marketing of QuEChERS products by several vendors.
Technical Abstract: This article describes the comparison of different versions of an easy, rapid, and low-cost sample preparation approach for the determination of pesticide residues in fruits and vegetables by concurrent use of gas and liquid chromatography (GC and LC) coupled to mass spectrometry (MS) for detection. The sample preparation approach is known as QuEChERS, which stands for “quick, easy, cheap, effective, rugged, and safe.” The three compared versions include the original unbuffered method, which was first published in 2003, and two interlaboratory validated versions: AOAC Official Method 2007.01, which uses acetate buffering, and European Committee for Standardization (CEN) Standard Method EN 15662, which calls for citrate buffering. LC-MS/MS and GC-MS analyses using each method were tested from 50-1000 ng/g in apple-blueberry sauce, peas, and limes spiked with 32 representative pesticides. As expected, the results were excellent (overall average of 98% recoveries with 10% RSD) using all 3 versions, except the buffered methods gave improved recoveries for the few pH-dependent pesticides. The different methods worked equally well for all matrices tested with equivalent amounts of matrix co-extractives measured, matrix effects on quantification, and chemical noise from matrix in the chromatographic backgrounds. The AOAC version gave higher and more consistent recoveries for pymetrozine than the CEN method in all 3 matrices and for thiabendazole in limes.