Development and validation of a generic nontarget method based on liquid chromatography – high resolution mass spectrometry analysis for the evaluation of different wastewater treatment options

Abstract

AbstractA comprehensive workflow for using nontarget approaches as process evaluation tools was implemented, including data acquisition based on a LC–HRMS (QTOF) system using direct injection and data post-processing for the peak recognition in “full scan” data. Both parts of the approach were not only developed and validated in a conventional way using the suspected analysis of a set of spiked known micropollutants but also the nontarget analysis of a wastewater treatment plant (WWTP) effluent itself was utilized to consider a more environmental relevant range of analytes. Hereby, special focus was laid on the minimization of false positive results (FPs) during the peak recognition. The optimized data post-processing procedure reduced the percentage of FPs from 42% to 10–15%. Furthermore, the choice of a suitable chromatography for biological treated wastewater systems was also discussed during the method development. The workflow paid also attention to differences in the performance levels of the LC–HRMS system by implementation of an adaption system for intensity variations comparing different measurements dates or different instruments. The application of this workflow on wastewater samples from a municipal WWTP revealed that more than 91% compounds were eliminated by the biological treatment step and that the received effluent contained 55% newly formed potential transformation products