Clean-up Procedure Development and Method Validation for Pesticide Residues Analysis in Carrots

In this work, a method was developed, validated, and applied to determination of ten pesticide residues (trifluralin, carbofuran, chlorothalonil, pendimethalin, captan, tebuconazole, pyraclostrobin, difenoconazole, deltamethrin, and azoxystrobin), from seven distinct classes, in carrot samples, employing a QuEChERS procedure for the analyte extraction and gas chromatography coupled to mass spectrometry (GC-MS) for quantification. The dispersive clean-up step was optimized using different sorbents at different concentrations and mixings. The method proved to be efficient and robust, showing recoveries in the range 72-117%, and RSD ranging from 4.9 to 16.6% (except for chlorothalonil and captan) at fortification levels of 45, 90, 180, and 450gkg(-1) with seven replicates analyzed for each level (n=28). Chlorothalonil and captan could not be validated due to analyte stability problems. Detection limits were between 15 and 45gkg(-1), and the quantification limits were between 45 and 90gkg(-1). The method was successfully applied to real samples.