SALLE combined with LD-DLLME for pesticides analysis in sugar and soil samples

Abstract

In this study, a modified salting-out-assisted liquid-liquid extraction (SALLE) combined with low density dispersive liquid-liquid microextraction (LD-DLLME) has been developed for quantitative determination of multiclass pesticide residues (atrazine, diazinon, ametryn, terbutryn, chlorpyrifos, dimethametryn, 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE), 4,4'-dichlorodiphenyldichloroethane (4,4'-DDD) and 4,4'-dichloro- diphenyltrichloroethane (4,4'-DDT)) levels in sugar and soil samples coupled with gas chromatography–mass spectrometry (GC-MS) detection. The extract was enriched after combining SALLE to LD-DLLME and enrichment factor obtained ranged 30-121. Under the optimum conditions, the linearity of the method was in the range of 6.25–100 ng g-1 for atrazine, ametryn, terbutryn, dimethametryn and 4,4'-DDT, and in the range of 2.5–100 ng g-1 for diazinon, chlorpyrifos and 4,4'-DDD, and in the range of  1–100 for 4,4'-DDE with correlation coefficient of  0.992 or better. The limits of detection (LODs) ranged from 0.01–0.25 ng g-1. The precisions as %RSD, were below 10% for both matrices. The recoveries obtained from spiked sugar and soil samples at 5 and 50 ng g-1 ranged from 79 to 111%. The method was subsequently applied to real sugar and soil samples. All the pesticides investigated were not detected in the sugar sample. The soil sample was contaminated by atrazine and ametryn at concentration level of 0.3 and 0.2 ng g-1, respectively.                     KEY WORDS: SALLE, LD-DLLME, Extraction, Pesticide residues, Sugar, Soil   Bull. Chem. Soc. Ethiop. 2021, 35(1), 1-16. DOI: https://dx.doi.org/10.4314/bcse.v35i1.1