Study on spatio-temporal sequences and exploring health risk assessment of emerging pollutants in tap water based on nontarget screening
Objective Based on ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-QTOF-MS/MS),a nontarget screening strategy was adopted in analyzing and identifying emerging pollutants(EPs)in tap water across the country,and studying its spatial and temporal distribution characteristics.Methods After extracting tap water samples by solid phase extraction,mobile phases(0.1%aqueous formic acid and methanol solutions)was used to elute the sample on a C18 chromatographic column.The nontarget screening strategy was used to acquire the MS information in full scan mode.We extracted and analyzed the chromatographic and mass spectral peaks,then searched the spectral library to compare the exact mass numbers,and the secondary MS/MS spectra fragment ion information was compared one by one.Finally,the retention time and the mass spectrum data of candidate EPs were identified and analyzed with the data of standard samples.then quantified by the internal standard method.Results A total of 135 EPs were initially screened from tap water across the country and 24 with high chromatographic peak response were finally selected and verified by standard products,including 6 pharmaceuticals,13 pesticides,3 industrial compounds and 2 food additives.Nine of them showed detection rates of more than 60%,such as canrenone,medroxyprogesterone,hydrocortisone acetate,etc.The concentrations of detected pollutants range from ND 422.63 ng/L.And the four contaminants with higher average concentrations were canrenone,medroxyprogesterone,hydrocortisone acetate and tris(2-butoxyethyl)phosphate.Conclusion In this study,a nontarget strategy based on UPLC-QTOF-MS/MS was adopted to screen potential unknown pollutants with no-standards,and explored the overall contamination status of tap water samples.This contributed to more comprehensive understanding of the EPs distribution,and provided technical support for monitoring the EPs in tap water.
Tap waterNontarget screeningEmerging pollutantsSpatial and temporal distributionRisk evaluation
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NSTL
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