Modified QuEChERS method for the determination of s-Triazine herbicide residues in soil samples by high performance liquid chromatography-diode array detector

Abstract

A modified QuEChERS method has been proposed for the quantitative determination of four s-triazine herbicides including atrazine, secbumetone, aziprotryne and terbutryn by high performance liquid chromatography with diode array detector (HPLC–DAD) from soil samples collected from different localities in Ethiopia. Different parameters affecting the chromatographic separations and extraction efficiency of the target analytes were studied and optimum conditions were obtained. Under the optimum conditions wide linearity range, i.e., from 7.2–200 ng g^-1, with coefficients of determinations of 0.995 or better were obtained. The limits of detections (LODs) and quantifications (LOQs) determined as 3 and 10 times the signal-to-noise ratio (S/N) were in the range of 2.2–8.3 ng g^-1 and 7.2–27.8 ng g^-1, respectively. Intra- and inter-day precision studies of the proposed method, expressed as relative standard deviations (RSD) were in the range of 1.0–6.8% and 2.0–8.1%, respectively. The recoveries of the spiked soil samples collected from four different localities including Teji River, Ziway Lake, Atsebela River and Hawassa Lake area agricultural farmland soil samples, were in the range of 71–100% with the corresponding RSD ranging from 1.7–9.9%. The results of the study demonstrated that the developed method involves efficient sample preparation allowing the extraction of the target analytes, followed by the use of HPLCDAD for quantitative analysis.

Keywords: Modified QuEChERS; s-Triazine herbicides; Soil samples; HPLC-DAD