The loss and fate of BaA, Chr, BbF, and BaP (PAH4) tracked by stable isotope during frying

•The loss rate of PAH4 during frying was simulated by stable isotope PAH4-d12.•Effect of frying temperature on PAHs loss is higher than the initial PAHs content.•The loss rate of BaP is the highest, while that of BbF is the lowest during frying.•The partial fate of PAHs is confirmed by identifying the conversion products.•The loss and conversion of PAHs are related to oil oxidation during frying. The objective of this work was to accurately quantify the loss of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(a)pyrene (PAH4) and investigate the fate of the lost PAH4 into their derivatives during frying. Stable isotopes (PAH4-d12) were used to simulate the loss and track the conversion of PAH4. The results showed that the rate of loss of PAH4-d12 increased with the increase of frying temperature and the loss rate of benzo(a)pyrene-d12 was the largest, indicating that benzo(a)pyrene had the strongest chemical reactivity during frying. Moreover, the identification of five PAH4 derivatives has confirmed the conversion of lost PAH4. Finally, the loss of PAH4 during frying positively correlated with the oxidation of oil, and a conversion mechanism of PAHs to derivatives was proposed. This work directly proved the loss and conversion of PAH4 and provided a comprehensive perspective for studying the changes in PAH4 during frying.