Submitted to: Journal of Food Additives & Contaminants
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/28/2010
Publication Date: 10/1/2010
Citation: Kmellar, B., Abranko, L., Fodor, P., Lehotay, S.J. 2010. Routine approach to qualitatively screen for 300 pesticides and quantify those frequently detected in fruits and vegetables using liquid chromatography tandem mass spectrometry. Journal of Chromatography A. 27(10):1415-1430. Interpretive Summary: The routine monitoring of hundreds of pesticide residues in foods is a challenging analytical task. Sample preparation and analysis techniques have improved greatly in recent years. However,the data processing, interpretation, and review of so much information generated using modern instruments in a rapid, efficient, and reliable manner have become the bottleneck. Any mistakes made can be either costly to the producer of the food which has been unjustly condemned or to the consumer who is exposed to violative pesticide residues. This work describes a process to streamline data handling and interpretation of results for 300 pesticide analytes in many types of fruits and vegetables, and how the method was implemented in a routine monitoring laboratory. The study describes the pros and cons of conducting a two step process in which the sample extracts are first screened for 300 residues and then those extracts found to be positive are analyzed by a second method for confirmation and quantification. Laboratories worldwide that conduct monitoring of pesticide residues for trade and other purposes will benefit from the information given in the paper.
Technical Abstract: This paper describes an efficient and effective analytical scheme to first screen for 300 pesticides in fruit and vegetables samples using liquid chromatography tandem mass spectrometry (LC-MS/MS) with a commercial enhanced product ion method. Then, the presumed positive extracts were analyzed using a quantitative and confirmatory LC-MS/MS method optimized for 55 pesticides. QuEChERS with acetate buffering (AOAC Official Method 2007.01) was used for sample preparation, which has been previously shown to yield high quality results for hundreds of pesticide residues in foods. The advantages and disadvantages of both the qualitative screening and quantitative/confirmatory methods and their combination are critically discussed. No false negatives for the 55 pesticides occurred above 10 ng/g for extracts analyzed by both LC-MS/MS methods, and the few false positives from the screening method were very likely eliminated by the second analysis. The monitoring scheme was applied during a one-year period on 200 fruit and vegetable samples from Hungarian markets. No pesticide residues were found in half of the samples, and 12 violations of European maximum residue limits were determined.