Development and validation of analytical method for acidic pesticide residues determination in water using LC-MS/MS: a one year surveillance program for two Egyptian governorates

Abstract

ABSTRACT An applicable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is developed to enable the efficient residue detection of fifteen acidic pesticides in water (drinking, ground, irrigating, and agricultural drainage water). The extraction and sample concentration were accomplished using the solid-phase extraction (SPE) technique. The developed method was fully validated according to the EU validation guidelines. The accuracy and precision calculations were evaluated by sample fortifications at concentrations of 0.1–1.0 µg/L. Acceptable recoveries and precisions were obtained of 70–120% and below 20%, respectively. The method showed good linearity ≥0.995. The developed method’s quantitation limit was 0.1 µg/L for most studied pesticides. The uncertainty measurement, expressed as expanded uncertainty, in terms of relative standard deviation (at 95% confidence level) is within the range of ±44%. A survey study was successfully conducted by collecting 108 water samples from different water sources in Egypt during the period between June 2020 and May 2021. The obtained results showed the absence of residue for most of the acidic pesticides in the collected samples, except for bentazone which was present in 33% of the collected samples with a concentration range of 0.1 to 0.29 µg/L.