Residue Dynamic of Pyrimorph on Tomatoes, Cucumbers and Soil under Greenhouse Trails

Abstract

A modified QuEChERS method for analysis of pyrimorph residue in tomatoes, cucumbers and soil was developed and validated. Residue dynamics and final residues in greenhouse vegetables and soil were studied. At fortification levels of 0.05, 0.1 and 1 mg kg⁻¹ in tomatoes, cucumbers and soil, the method got recoveries ranged from 86.1% to 99.3% with relative standard deviations of 1.0%–7.7%, in agreement with directives for method validation in residue analysis. The limit of determination in tomatoes, cucumbers and soil was 0.05 mg kg⁻¹. The proposed method was successfully employed for the determination of pyrimorph residue levels and dissipation rates in vegetables and soil. At six experimental sites, pyrimorph residues in tomatoes and cucumbers showed relatively fast dissipation rates, with half-lives of 5.8–7.7 days and 5.7–7.1 days respectively. Half-lives of pyrimorph in soil were 8.5–11.0 days. The final residues of pyrimorph in tomatoes ranged from 0.19 to 3.66 mg kg⁻¹, 0.18 to 4.35 mg kg⁻¹ in cucumbers and 0.22 to 16.5 mg kg⁻¹ in soil with pre-harvest interval of 3–7 days. 5 mg kg⁻¹ was proposed as the MRL of pyrimorph in tomatoes and cucumbers.