Magnetic Deep Eutectic Solvent-Based Single-Drop Microextraction for the Determination of Triazine Herbicides in Environmental Waters

A magnetic deep eutectic solvent-based single-drop microextraction technique coupled with high-performance liquid chromatography (MDES-SDME-HPLC) was established for the determination of five triazine herbicides in environmental water samples. MDES, used as the extraction solvent, was composed of heptanoic acid, methyltrioctylammonium chloride, and iron chloride. This pretreatment method requires only 50 μL of MDES, thereby avoiding the use of large volumes of toxic organic solvents. The MDES containing the target triazine herbicides was rapidly separated from the aqueous matrix by applying an external magnetic force, thus eliminating the need for centrifugation or additional reagents to achieve phase separation. The method demonstrated a linear range of 0.2–20 μg L−1, with a limit of detection of 0.06 μg L−1. Recoveries obtained from different environmental water matrices ranged from 75.5% to 102.4%. The greenness of the method was confirmed using five independent green analytical assessment tools. This approach represents a green and efficient analytical technique for detecting triazine herbicides in environmental water samples.