UPLC-MS/MS analysis of Sudan I, butylated-hydroxytoluene and its major metabolites from sampling sites along the Nile River-Egypt: Environmentally evaluated study

摘要

The environmental analysis of butylated-hydroxytoluene (BHT), a widely used synthetic phenolic antioxidant, and its metabolites, have attracted wide attention due to their increasing levels and high toxicities. Sudan I, a carcinogenic azo-dye, has also presented itself as an emerging pollutant in environmental samples. A method based on ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in electrospray ionization mode has been developed for the analysis of Sudan I, BHT and its metabolites, 2,6-di-tertbutyl-1,4-benzoquinone (BHT-Q) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH), in Nile River water samples. A modified dispersive liquid-liquid extraction technique was employed and optimised for the extraction of the target analytes. The method detection limits ranged from 0.31 ng mL(-1) and up to 4.79 ng mL(-1) . The total recoveries varied from 89.25% to 115.19%, with relative standard deviations (n = 5) less than 3.60% at different spiking levels. The optimized method was applied to the river water samples from 2 sites, where samples from the river bank and from the midstream were collected and analysed. In general, it was observed that concentrations of the 4 analytes varied in the range of 11.01-1351.19 ng mL(-1) . River banks also showed higher concentration levels than midstream samples, which could be due to the high hydrophobicities of the analytes that led to their sorption to suspended matters and sediment. The greenness of the proposed method was evaluated, and it was found to be more environmentally acceptable than other LC-MS/MS studies reported for the same target analytes in the literature.