LC–MS/MS analysis of seven strobilurin fungicides in grape berries, raisins, and grape leaves: occurrence, compliance, and dietary risk assessment

Résumé fourni par la source

Abstract A matrix-adapted QuEChERS/LC–MS/MS workflow was validated for seven strobilurin fungicides in grape berries, grape leaves, and raisins and applied to 200 retail samples marketed as domestically produced in Najran, Saudi Arabia: 100 grape berry, 50 grape leaf, and 50 raisin samples. The method showed satisfactory selectivity and matrix-matched linearity (R² = 0.9948–0.9995). Verified LOQs were 1–5 µg/kg in grape berries, 10–50 µg/kg in grape leaves, and 1–10 µg/kg in raisins. Recoveries ranged from 80.6% to 102.1%, with RSDs of 4.0%–13.8%. Target fungicides were detected in 88.0% of grape berry samples, 100.0% of grape leaf samples, and 82.0% of raisin samples. Grape leaves had the highest observed detection frequency and greatest comparative residue-limit concern, although positive concentration distributions of the four detected fungicides did not differ significantly among commodities. EU limits for grape leaves were used only as external comparative reference values because no applicable SFDA or Codex MRLs were identified for this commodity; therefore, these comparisons were not interpreted as formal Saudi non-compliance. In grape berries, one kresoxim-methyl result slightly exceeded the Saudi MRL directly, but no sample remained non-compliant after applying 50% expanded measurement uncertainty. In raisins, trifloxystrobin, pyraclostrobin, and kresoxim-methyl were below the applicable SFDA MRLs, whereas azoxystrobin in raisins was reported descriptively because no applicable SFDA or Codex MRL was identified for this compound–commodity combination. All chronic exposure estimates were below 0.35% of the corresponding ADIs. Pyraclostrobin in grape berries reached 179.1% of the ARfD for children, while all other acute estimates remained below 100% under the stated direct or surrogate assumptions. The findings apply only to the sampled Najran retail market.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.