Quantitative analysis of bromate in non-alcoholic beer using ultra performance liquid chromatography-electrospray ionization mass spectrometry

Abstract

Bromate (BrO3−) is a possible human carcinogen which is formed as a bromide containing source water ozone disinfection by-product. Thus, BrO3− is subject to assess its threat to humans. In the present study, an ultra performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the quantitative analysis of BrO3− in non-alcoholic beer. The chromatographic separation of both transitions 81BrO3− and 79BrO3− (isotope contributions of 79Br and 81Br) was carried out and achieved in 0.9999), precision (repeatability and reproducibility in terms of relative standard deviation) <1% at 1.0 μg mL−1 standard and <3% in the analysis of sample 1 (classic malt) and sensitivity with a low limit of detection (LOD, 81BrO3−, 0.03 ng mL−1 and 79BrO3−, 0.03 ng mL−1) and limit of quantification (LOQ, 81BrO3−, 0.1 ng mL−1 and 79BrO3−, 0.1 ng mL−1) in the standard. Nevertheless, the LOD and LOQ in sample 1 (classic malt) were obtained only for transition 81BrO3−, 0.05 ng mL−1 and 0.16 ng mL−1, respectively. For transition 79BrO3− the obtained peak was below the limit of detection. A total of 39 non-alcoholic beer samples of different flavors were analyzed and the 81BrO3− level in classic samples was found between 1.20 μg mL−1 and 3.73 μg mL−1, however, in other flavored samples the concentration levels reached up to 14.04 μg mL−1 with excellent recovery rates (96–99%). In most of the analyzed real samples, only transition 81BrO3− was found nevertheless, transition 79BrO3− was either <LOD or completely diminished from the obtained sample chromatogram. This is one of the main findings from the present study and the mechanism of this cause is unknown. The obtained BrO3− levels were much higher than the limits in drinking water (10–25 ng mL−1) recommended by several regulatory agencies.