Determination of Dichlorodiphenyltrichloroethane from Soil Using Solid-liquid Extraction and Gas Chromatography–Electron Capture Detector

Abstract

Dichlorodiphenyltrichloroethane (DDT) pesticide has been banned around the world due to their adverse effect towards human health and environment. Most of the method development for the analysis of DDT is based on water matrices. Therefore, in this study, soil has been proposed as an alternative matrix in this study. The solid-liquid extraction (SLE) method was utilized to extract DDT from soil and analysis using optimized conditions of gas chromatography and electron capture detector (GC-ECD). N-hexane: deionized water containing 10 % NaCl with solvent ratio 1:9 was used in this study. The optimized method was validated by evaluating calibration curve, linearity, limit of detection (LOD), limit of quantification (LOQ), percentage recovery and intra-assay and inter-assay precision accuracy. From the calibration curve (0.20-5.00 ppm), good coefficient of determination was obtained at R2 = 0.9980. Limit of detection (LOD) and limit of quantification (LOQ) were obtained at 0.23 ppm and 0.78 ppm respectively. From intra and inter-assay lower coefficient variance (intra: 2.22 - 5.37 %; inter: 0.19 - 2.03 %) and lower percentage error were attained (intra: 7.36 - 8.68 %; inter: 5.66 - 9.89 %). A mean recovery of 93.24 % with good coefficient of variance (CV = 7.51 %) were also acquired. However, from the stability study (30 days) the decreasing pattern of recovery was obtained. The study showed that the analysis of DDT in soil is robust, hence it can be used as an alternative matrix for this analysis.