Validation of a multiresidue method for the analysis of 86 multiclass pesticides in litchi fruit by gas chromatography⇓Tandem mass spectrometry

Abstract

Background: Although India is an important producer of litchi fruit, there is hardly any validated method available for its pesticide residue analysis. This strongly warrants the need to standardize a simple multiresidue analytical method for efficient analysis of multiclass pesticides with specificity, sensitivity, and accuracy in a single chromatographic run in combination with MS determination. Objective: The aim of this study was to develop and validate a rapid ethyl-acetate-based sample preparation method for a simultaneous determination of 86 pesticides in litchi fruit by using GC–tandem MS. Methods: The method involved ethyl acetate as an extracting solvent and a combined salt system comprising sodium chloride and sodium sulphate for the organic layer separation. To obtain satisfactory recovery percentage of each pesticide studied here, this combination was selected for further validation based on selectivity, sensitivity, linearity, precision, and accuracy values. Results: The correlation coefficient (r2) of studied pesticides ranged between 0.97 and 0.99 at six concentration levels from 5 to 250 ng/mL. Furthermore, the average recovery values were within 70 and 120%, with repeatability relative SD below 20% for all 86 pesticides at the LOQ level and with an appreciable Horwitz ratio distribution that ranged between 0.5 and 2. Conclusions: All data demonstrate that the proposed method is adequately linear, accurate, and repeatable. Therefore, it can be widely used in commercial laboratories for analyzing pesticide residues for both domestic and export purposes. The method is in support of protecting consumer health. Highlights: A large-scale multiresidue method is reported for simultaneous analysis of a wide range of pesticides in litchi. The method complies with the regulatory requirements in terms of sensitivity for maximum residue limit compliance. The performance of the method complied with the SANTE guidelines of analytical QC.