Hydrophobic deep eutectic solvent based dispersive liquid-liquid microextraction for the preconcentration and HPLC analysis of five rice paddy herbicides in water samples

Herbicides are widely used in agricultural production, which causes serious pollution to the environment, especially the water environment, and increases the environmental burden. In the present study, a deep eutectic solvent-based dispersive liquid-liquid microextraction method (DES-DLLME) followed by high performance liquid chromatography (HPLC) was developed for the determination of five herbicides from water samples. The factors influencing of DES type, DES and sample volume, dispersant and salt were studied and optimized. Under the optimal experimental conditions, five herbicides had a good linear relationship (r(2) >= 0.998) within wide concentration ranges (100 similar to 250000 mu g L-1), and the inter-day and intra-day precision was between 0.04% and 7.11%; the mean extraction recoveries were ranging from 70.38 to 122.91%, and the range of the enrichment factors (EFs) were from 19.34 to 98.09. Finally, this method was successfully used to analyze 11 environmental water samples. All the experimental results showed that this is a simple, economical and environmentally friendly method for sample determination. Hydrophobic DES as the extractant exhibited good extraction efficiency to preconcentrate five herbicides commonly used in rice paddies for the first time, which provided a new approach for expanding the application of DES in the herbicides extraction in DLLME technology.

Automated summary

A new method based on a hybrid solvent was developed for the determination of five herbicides from water samples. The method showed good precision, recovery, and environmental friendliness, making it a simple and cost-effective approach for sample determination.