Analysis of triazine herbicides using an up-and-down-shaker-assisted dispersive liquid–liquid microextraction coupled with gas chromatography–mass spectrometry

In dispersive liquid–liquid microextraction, a few hundred microliters to a few milliliters of water-miscible dispersive solvent are commonly used to assist emulsification in aqueous samples. In the present study, a consistent and automatic up-and-down-shaker-assisted dispersive liquid–liquid microextraction (UDSA-DLLME) that does not require a dispersive solvent was developed. The enrichment factors (EFs) of the targets obtained using the automatic shaker were 361–1391 for UDSA-DLLME, 51–77 for ultrasonication, and 298–922 for vortexing. The linearity of the method was in the range 0.2–200 μg L−1, and its limit of detections was within 0.02–0.04 μg L−1. The intraday and interday relative standard deviations ranged from 5.7 to 10.0% and 5.5 to 10.3%, respectively. The relative recoveries of river and lake samples spiked with 2.0 μg L−1 of triazines were 94.2–102.2% and 98.5–104.1%, respectively. The technique provided high repeatability and recovery. No matrix interference from river and lake water was observed. The method also achieved high EFs compared with those obtained through other emulsification methods such as vortexing and ultrasonication. UDSA-DLLME is an alternative sample preparation technique with good performance.