Determination of perfluorinated compounds， antibiotics and pesticides in drinking water by automated solid phase extraction with ultra-performance liquid chromatography-tandem mass spectrometry

Emerging organic contaminants in drinking water, characterized by biological toxicity and environmental persistence. Developing effective strategies for monitoring and controlling these contaminants in drinking water has become an urgent need to ensure drinking water safety. However， the current detection technologies for emerging organic contaminants in drinking water mainly focus on analyzing a single type of pollutant， which increases in detection costs and fails to meet the urgent demand for rapid， multi-analyte screening in water quality monitoring. This study established a novel analytical method， which was based on the automatic solid phase extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry method （SPE-UPLC-MS/MS）， enabling the simultaneous detection of 30 contaminants with diverse physicochemical properties in drinking water. The 30 contaminants included perfluorinated compounds （PFCs）， antibiotics and pesticides. The water samples were pretreated automatically by an automatic solid phase extraction instrument， and then purified and enriched through an OASIS HLB solid phase extraction column. The 30 contaminants were separated on an ACQUITY UPLC HSS T3 column （100 mm×2.1 mm， 1.7 μm） with a gradient mobile phase consisting of 5 mmol/L ammonium acetate （containing 0.1% formic acid） and acetonitrile. The samples were analyzed and determined by the positive/negative switching mode of the electrospray ionization source， and quantified by the external standard method. The results showed that the 30 compounds had good linear relationships within the mass concentration ranges of 0.10-200.0 μg/L， and the correlation coefficients （r） greater than 0.990. The limits of detection were 0.01-1.0 ng/L， and the limits of quantification were 0.03-3.0 ng/L. The 30 compounds exhibited recoveries in the range of 70.2%-120.0% at three levels （0.20， 1.0， 10.0 μg/L）， and the relative standard deviations （RSDs， n=6） were 3.2%-9.6%. Water samples from nine counties and districts in Hunan Province were analyzed using the developed method. The 16 compounds were detected， with the mass concentration range of 0.1-9.9 ng/L. Among these， atrazine was the most frequently detected， whereas the highest concentration observed was chlorantraniliprole. According to the control requirements specified in GB 5749-2022 Standards for Drinking Water Quality， the contents of perfluorooctanoic acid， 2，4-dichlorophenoxyacetic acid， atrazine， carbofuran， and bentazone were significantly lower than the national standard limits， indicating a low health risk associated with these compounds in the source water of the studied regions. This method is efficient， rapid， and cost-effective， which is suitable for the simultaneous determination of PFCs， antibiotics， and pesticides in drinking water. This method provides strong technical support for the control and treatment of new contaminants in drinking water.