Complete Characterization of Degradation Byproducts of Bemotrizinol and Degradation Pathway Associated with Sodium Hypochlorite Treatment

TL;DR

This study identifies 19 byproducts formed when the UV filter bemotrizinol degrades using sodium hypochlorite, a common disinfectant in water treatment.

Contribution

The study provides a complete characterization of bemotrizinol degradation byproducts and proposes a plausible reaction mechanism.

Findings

Nineteen degradation byproducts of bemotrizinol were isolated and identified.

A plausible degradation pathway was proposed based on the identified byproducts.

The study used advanced chromatographic and spectroscopic methods to analyze the byproducts.

Abstract

The aim of this study was to elucidate all the degradation byproducts (DBPs) of bemotrizinol (BEMT) that are associated with sodium hypochlorite treatment. BEMT is a UV filter that is found not only in many personal care products, such as sunscreen and cosmetics, but also as an additive in plastics or clothing to protect them from damage that results from absorbed radiation. BEMT has been detected in wastewater, surface water, and some lake sediments, in quantities from a few ng/L to hundreds of ng/L, to such an extent that, today, it is considered an emerging pollutant. In this study, the UV filter was subjected to oxidation with sodium hypochlorite, which is an oxidant at the base of the disinfection process that is used in most wastewater treatment plants or in swimming pools. Using different chromatographic methods (CC, TLC, HPLC, and GC), the resulting DBP mixture was separated into its main components, which were then identified using one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. Nineteen DBPs were isolated, and a plausible reaction mechanism was proposed to explain how they were obtained.

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