Quantitative analysis of bisphenol A eluted into canned tomato and mackerel by matrix-assisted laser desorption ionization mass spectrometry using anthracene as matrix

Quantitative analysis of bisphenol A (BPA) was performed by matrix-assisted laser desorption ionization mass spectrometry. It was found that BPA was ionized as deprotonated species when anthracene was used as the matrix. A peak of deprotonated BPA and a peak assignable to epoxy resin were observed on analysis of liquids in canned tomato and mackerel samples. In addition, many identical peaks were observed from the liquids in both cans, indicating that epoxy resin was degraded and BPA was eluted into the canned tomato and mackerel during the storage period. It was suggested that the mackerel heat-treatment process and the acidity of tomato were responsible for the elution of BPA. Using bisphenol B (BPB) as the internal standard, the concentrations of BPA were determined to be 0.55 ± 0.05 and 1.72 ± 0.13 ng/µL (µg/mL) for the canned tomato and mackerel samples, respectively. These canned products were imported goods, and their BPA levels exceeded the safe concentration recommended by The Can Manufacturers Institute of Japan. The results indicate that consumers should exercise caution when consuming canned products particularly those manufactured overseas, which have different safety standards. Graphical abstract