A MIL-53-PVDF mixed-matrix membrane for dispersive membrane solid-phase extraction of phenoxycarboxylic acid...

A MIL-53-PVDF mixed-matrix membrane was prepared for the enrichment of four phenoxycarboxylic acid herbicides (2,4-D, MCPA, 2,4-DP, and 2,4-DB) in environmental water samples, and the enriched analytes were determined by high performance liquid chromatography (HPLC). Several variables affecting the extraction efficiency were systematically investigated. Under optimized conditions, the linear ranges of 2,4-D, MCPA, and 2,4-DB were 0.1-50 µg L^-1, while that of 2,4-DP was 0.4-50 µg L^-1. The correlation coefficients (r) were all greater than 0.9993. The method detection limits (MDLs) ranged from 0.132 to 0.363 µg L^-1, and the limits of quantitation (LOQs) ranged from 0.528 to 1.452 µg L^-1. The intra-day and inter-day precisions (relative standard deviation, n = 6) at three spiked levels were 1.36-13.10% and 1.77-13.63%, respectively. For the established method, the recoveries of tap water samples spiked at high, medium, and low concentrations were 72-125%, while those of surface water and seawater samples were 84-116% and 77-122%, respectively. The proposed method is simple and easy to operate, can sensitively determine phenoxycarboxylic acid herbicides in water, and exhibits practicability.