Evaluation of dilute-and-shoot and solid-phase extraction methods for the determination of S-metolachlor and metolachlor-OA in runoff water samples by liquid chromatography tandem mass spectrometry

Abstract

In this study, two fast methods, i.e., the dilute-and-shoot one and the solid-phase extraction (SPE) procedure, were evaluated for the determination of S-metolachlor and metolachlor-OA in runoff water samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). The limits of quantification of both analytes were 2 μg L⁻¹ and 0.02 μg L⁻¹, by dilute-and-shoot and SPE, respectively. Good accuracy (86–114%) and precision (≤20%) were found. Besides, these methods were statistically similar. Thus, firstly, dilute-and-shoot is a promising alternative to analyzing samples with high levels of both analytes. Secondly, samples with low levels of both analytes can be submitted to SPE. Both methods were successfully employed, since they enabled the determination of S-metolachlor and metolachlor-OA in runoff water samples at concentrations between 0.082 and 267 μg L⁻¹.