Residue Analysis of Mepronil Fungicide in Soil

Studies on the Residue of Mepronil Fungicide in Crops and Soils (Part 2)

Abstract

A highly sensitive method for analysis of mepronil in soil was established by ECD-gas chromatography. The method consisted of sequential procedures of extraction by refluxing soil samples, liquid-liquid partition, bromination, silicagel column chromatography, and determination. Extraction efficiency was investigated using soil samples prepared by allowing to stand under the submerged or the upland condition for a long time over 2 months after application of mepronil. A mixture of methanol and 12N potassium hydroxide (3+1, v/v) was the best solvent for extraction of mepronil among several solvents tested. Refluxing with the solvent raised the efficiency. Recovery was more than 90% for 5 soils under the flooded condition, when mepronil was added at concentrations from 0.03 to 6.0ppm, and above 80% for 4 soils under the unflooded condition, when added at concentrations from 0.6 to 6.0ppm. The lower detection limit of mepronil in soil is calculated as 0.005ppm.