Integrated LC–MS/MS assessment of cyprodinil and fludioxonil residues in greenhouse strawberries: Dissipation, dietary risk and washing removal under Saudi Arabian conditions

Abstract

Cyprodinil and fludioxonil are commonly applied fungicides in strawberry cultivation, but integrated information on their analytical determination, dissipation, terminal residues, dietary exposure, and post-harvest washing under Saudi greenhouse conditions remains limited. This study investigated the residue behavior of these fungicides in greenhouse-grown strawberries using a validated QuEChERS–LC–MS/MS method. Matrix-matched calibration showed excellent linearity for both analytes over 0.001–0.20 mg kg⁻ 1 , with coefficients of determination of 0.9999. Mean recoveries ranged from 91.78 to 97.82% for cyprodinil and from 90.26 to 94.46% for fludioxonil, with relative standard deviations within the SANTE acceptance criterion of ≤20%. The The limit of quantitation (LOQ) was 0.005 mg kg⁻ 1 for both compounds. Following application of a commercial 62.5% wettable granule (WG) formulation at 0.8 and 1.2 kg formulation ha⁻ 1 , both fungicides followed single first-order dissipation kinetics. Cyprodinil dissipated more rapidly than fludioxonil, with half-lives of 2.187–2.358 days and 2.565–2.606 days, respectively. Repeated applications maintained measurable terminal residues through day 10, with fludioxonil showing higher persistence than cyprodinil. Deterministic assessments of chronic and acute dietary risk, based on supervised trials median residue (STMR) and high residue (HR) values under Saudi intake scenarios, indicated low exposure. The highest chronic exposure reached 21.90% of the ADI for cyprodinil and 2.14% for fludioxonil, while the highest acute exposure reached 0.45% and 1.12% of the ARfD, respectively, all in children under the higher Saudi intake scenario. Washing efficacy was compound-dependent: cyprodinil removal was limited (20.96–42.41%), whereas fludioxonil removal was higher (65.10–94.22%). Under the most effective washing conditions, fludioxonil residues could be reduced below the MRL, whereas cyprodinil residues remained above the maximum residue limit (MRL). These findings support the combined use of validated residue monitoring, dissipation modeling, terminal-residue assessment, dietary exposure evaluation, and post-harvest mitigation studies to manage fungicide residues in protected strawberry cultivation.