Analysis and occurrence of benzotriazole ultraviolet stabilisers in different species of seaweed.

Benzotriazole ultraviolet stabilisers (BUVSs) are emerging compounds used in personal care products and in other products, such as plastics, to absorb UV light. BUVSs have been described as bioaccumulative, persistent and toxic, so it is of great interest to understand their presence in the environment. Some marine organisms, such as seaweeds, have been used as bioindicators of contamination in the environment because they are able to accumulate metals and organic compounds. We have selected seaweeds to develop a novel method to extract, identify and determine six BUVSs (UV P, UV 326, UV 327, UV 328, UV 329, UV 360) based on microwave assisted extraction (MAE) and ultra-high-performance liquid chromatography with diode array (UHPLC-DAD) and mass spectrometry confirmation (UHPLC-MS/MS). Under optimum conditions, recoveries ranging from 49.8 to 92.3% were obtained, while intra-day and inter-day precision values were lower than 10% for most of the compounds. Limits of detection in the ranges 1.79-4.58 and 0.89-1.76 ng g-1 dry weight (dw) were obtained for UHPLC-DAD and UHPLC-MS/MS, respectively. The optimised method was applied for the analysis of twelve species of seaweed sampled during four months in 2018 from Las Canteras beach (Gran Canaria, Spain), with the results confirmed by UHPLC-MS/MS. UV 360 was found in concentrations between 42.5 and 115 ng g-1 (dw) in five of the twelve species. Although the highest concentrations were found in Asparagopsis taxiformis, the presence of UV 360 in other species could suggest that seaweeds can act as potential bioindicators of the occurrence of these compounds in the coastal environment.