A data-independent acquisition approach based on HRMS to explore the biodegradation process of organic micropollutants involved in a biological ion-exchange drinking water filter

• Published in: Chemosphere (Oxford) 2021-08, Vol.277, p.130216, Article 130216
• Main Authors: Solliec, Morgan, Roy-Lachapelle, Audrey, Storck, Veronika, Callender, Katrina, Greer, Charles W., Barbeau, Benoit
• Format: Article
• Language: English
• Subjects: Data-independent acquisition; High-resolution mass spectrometry; Non-target screening; Organic micropollutants removal; Water treatment
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.130216

Drinking water producers continuously develop innovative treatment processes to effectively remove organic micropollutants from raw water. Biological ion-exchange (BIEX) water treatment is one of these new techniques under development and showing great potential. In order to investigate if biodegradation is highly involved in such a removal technique, cultures were prepared with microorganisms sampled on the resins of a BIEX filter. Then, organic micropollutants were spiked into these cultures and their (bio)degradation was followed over 30 days by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). The purpose of this study was firstly to develop an analytical method using UHPLC-HRMS able to monitor the degradation of three spiked organic micropollutants in culture. Beyond quantification, this method allowed the simultaneous recording of fragmentation information via the use of a data-independent acquisition approach to perform a non-exhaustive search of transformation products related to the spiked micropollutants in culture aliquots. Secondly, a data treatment approach was developed to process raw spectral data generated by aliquots analysis by optimizing the precursor isolation mass windows, the accurate mass tolerance, peak intensity thresholds and choice of database. The use of this new method with a post-data acquisition treatment approach completed by the exhaustive study of fragmentation spectra allowed the tentative identification of 11 transformation products related to the spiked compounds. Finally, 16S rRNA gene amplicon sequencing revealed that bacterial genera known for their ability to degrade the spiked micropollutants were present in the microbial community of the BIEX drinking water filter. [Display omitted] •Cultures containing microorganisms taken from a water filter were spiked with micropollutants.•An analytical method was used to monitor the biodegradation of micropollutants.•Data-independent approach allowed an untargeted screening of transformation products.•Transformation products of the spiked micropollutants were identified.•This approach helped to highlight the implication of biodegradation in a water treatment process.