Immersed solvent microextraction and gas chromatography–mass spectrometric detection of s-triazine herbicides in aquatic media Original Research Article

An immersed solvent microextraction (SME) method was successfully developed for the trace enrichment of s-triazine herbicides from aquatic media. A microdrop of butyl acetate was applied as the extraction solvent. After extraction, the microdrop was introduced directly into a gas chromatography–mass spectrometry (GC–MS) injection port. Some important extraction parameters such as type of solvent, extraction time, stirring rate, and temperature were investigated and optimized. The highest possible microdrop volume of 3 μl, a sampling temperature of 60 °C, and use of butyl acetate are major parameters to obtain high enrichment factors. The enrichment factor and linearity was studied by preconcentration of 1 ml of HPLC-grade, rice farm water and river water, spiked with a standard solution of triazines at a concentration range of 0.1–100 μg l−1 (R.S.D. < 11%). The correlation coefficient was satisfactory (r2 > 0.98) for all the studied triazines. Detection limits were obtained using HPLC-grade and river water, i.e. 0.015–0.4 μg l−1. The effect of matrix on extraction efficiency was, also, studied using some real-life water samples.