Development and validation of a multiresidue method for determination of 37 pesticides in soil using GC-NPD

In this study, a multiresidue analytical method for the detection of 37 pesticides in a soil matrix was developed and validated. The soil sample was fortified with a known quantity of pesticides at two different concentration levels (0.1 and 0.01 µg/g) and the analytes were extracted via a liquid-solid extraction method. The pesticides were separated on an HP5 capillary column and were analyzed with a gas chromatograph coupled to a nitrogen-phosphorous detector (GC-NPD). Method validation was accomplished with good linearity (r(2) = 0.994-0.999) within a considerable range of concentrations. Satisfactory recoveries (70.5-110.4%) were obtained with 32 pesticides at both spiking concentration levels, whereas five pesticides-dimepiperate, buprofezin, prometryn, pirimicarb, and fludioxonil-were recovered at relatively low levels (43.6-61.8%). The applicability of the method was demonstrated by analyzing field samples collected from 24 different sites around Yeongsan and Sumjin rivers in the Republic of Korea. No residues of the selected pesticides were detected in any of the samples. The developed method could be employed as a simple and cost-effective method for the routine detection and analysis of 37 pesticides in soil samples.