Simultaneous Determination of Low Molecule Benzotriazoles and Benzotriazole UV Stabilizers in Wastewater by Ultrasound-Assisted Emulsification Microextraction Followed by GC-MS Detection

Abstract

A rapid, sensitive, economically and ecologically friendly method based on one-step ultrasound-assisted emulsification microextraction (USAEME) and in situ derivatization followed by gas chromatography-mass spectrometry (GC-MS) for simultaneous determination of low molecular benzotriazoles (LMBTs) and benzotriazole-based ultraviolet filters (BUVs) was developed. The optimized method allow quantification of benzotriazole (BT), 4-methylbenzotriazole (4MBT), 5-methylbenzotriazole (5MBT); 5-chlorobenzotriazole (5ClBT), 2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzortriazole (UV326) and 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole (UV329) in municipal and industrial (dairy) wastewater. The method was validated using real influent and effluent wastewater and samples at various stages of the purification process. Obtained relative recoveries were between 77 and 137%, limits of detection (LoDs) from 0.001 to 0.035 µg/L, the repeatability expressed by the coefficient of variation (CV) did not exceed 12%. The use of the method for the determination of the tested compounds in municipal and industrial wastewater showed their presence in most of the tested samples, in concentrations from LoD to 6.11 µg/L. The conducted studies of samples from municipal wastewater treatment plant (WWTP) located in north-eastern Poland showed that the effectiveness of benzotriazole removal by this plant is from 29 to 84%. The load of tested compounds released into the environment by this facility ranges from 2 to 269 mg/day/1000 inhabitants.