Quenchers in advanced oxidation technologies for analysis of micropollutants by liquid chromatography coupled to mass spectrometry: Sodium sulphite or catalase?

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Ana M. Gorito (Author) Other; Marta O. Barbosa (Author) Other; C. Marisa R. Almeida (Author) Other; Manuel Fernando R. Pereira (Author) FEUP; Adrián M. T. Silva (Author) FEUP; Ana Rita Ribeiro (Author) FEUP

Journal

Title: Science of the Total Environment

Vol. 692

Pages: 995-1004

ISSN: 0048-9697

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 3 Citations

Associated Projects

InSpeCt - Identifying and interrupting micropollutants of EU concern by using Smart Carbon materials

SAMPREP - Novas técnicas miniaturizadas de preparação de amostra para determinação de micropoluentes em matrizes ambientais

Other information

Authenticus ID: P-00Q-W9M

DOI: 10.1016/j.scitotenv.2019.07.278

Abstract (EN): This work aimed to investigate the possible effect of 2 quenchers commonly used in H2O2-based advanced oxi-dation technologies (AOTs), i.e. catalase and sodium sulphite (Na2SO3), on the analytical signal of 3 detectors coupled to liquid chromatography (LC): tandem mass spectrometry (LC-MS/MS), fluorescence detection (LCFD) and LC-diode array detection (LC-DAD). The observation of analytical interferences fora group of compounds when studying the removal by continuous mode UV/H2O2 of 26 micropollutants (MPs) from a spiked surface water (SW), for which the residual H2O2 in the samples was quenched by Na2SO3, triggered the need of understanding these effects and thus catalase was used as comparative quencher. From the 26 MPs having a wide range of polarity and pKa, those monitored after electrospray ionization (ESI) under positive ionization (PI) mode and presenting a pKa higher than 5.9 revealed a great signal suppression, but only when using Na2SO3 as H2O2 quencher. In this sense, we further explored this effect by selecting 2 MPs, metoprolol and diclofenac, which had respectively signal suppression and no interference in the LC-MS/MS response. These MPs were analysed be-fore and after addition of H2O2 and catalase or Na2SO3 in reaction vials, using: (i) different detectors coupled to LC, namely LC-MS/MS with ESI under PI and negative ionization (NI) modes, LC-FD and LC-DAD; (ii) different en-vironmental matrices (SW, drinking water, wastewater) and ultrapure water; and (iii) different magnitude levels (0.1-10 mg L-1). The results demonstrated a remarkable signal suppression in LC-MS/MS analyses under P1 mode for those compounds with pic higher than 5.9, confirming the interfering effect of H2O2/Na2SO3. To the best of our knowledge, the analytical interference in the LC-MS/MS analysis, after adding Na2SO3 to quench H2O2 in AOTs experiments was never reported before and the results presented herein support the recommendation to use catalase instead of Na2SO3 as quencher in AOTs studies.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10