D. Bertuola, A. Romanotto
Bisphenol A (BPA) is a co-monomer used as additive in the production of various materials, some of which are intended for the food industry: packaging, food storage containers, but also epoxy resins used for metal coating of cans. The human exposure to this substance can also occur through its migration in foods, that are in contact with the aforementioned materials [1]. The dangerous effects of BPA on human health, widely discussed over the years [2], [3], were reconsidered again in 2023 by EFSA, which set a new extremely low tolerable daily intake (TDI) for this compound [4].
The improvement of the BPA quantification in terms of sensitivity has therefore become an incontrovertible requirement of the food analysis; for this reason, we developed an analytical method for the quantification of BPA in canned food, exploiting the sensitivity and selectivity of the direct immersion SPME technique associated with the use of the multiple reaction monitoring spectrometry (MRM).
The main accomplished focuses of the method development were the achievement of a low detection limit (at least 1 ppb), the decrease of external contamination and the reduction of the SPME background phenomena, through ad hoc sample processing and cleaning procedures of the solid phase after the sample extraction. Possible overestimates or underestimates of the analyte concentration, caused by the matrix effect were eliminated through the use of the Bisphenol-A-(diphenyl-13C12) as internal standard. In all analysed matrices until now, it was possible to successfully detect both traces of BPA and the addition of BPA-13C at the set limit of 1 ppb, indicating a good efficiency of the used phase to adsorb and desorb this analyte and its isotope.
The advantages of the method are certainly the complete elimination of plastic equipment, the minimal sample preparation steps, the selectivity of the SPME-MRM coupling and the convenience of the BPA concentration calculation through the use of its carbon-13 isotope. We have therefore decided that, given these promising aspects, the method will now be optimized and validated, in order to monitor low levels of BPA in canned food samples.
[1] EFSA. An official website of the European Union. 2023. https://www.efsa.europa.eu/de/topics/topic/bisphenol
[2] World Health Organization & Food and Agriculture Organization of the United Nations. (2011). Joint FAO/WHO expert meeting to review toxicological and health aspects of bisphenol A : final report, including report of stakeholder meeting on bisphenol A, November 2010, Ottawa, Canada.
[3] Hengstler JG, Foth H, Gebel T, Kramer PJ, Lilienblum W, Schweinfurth H, et al. “Critical evaluation of key evidence on the human health hazards of exposure to bisphenol A”. April 2011. Critical Reviews in Toxicology. 41 (4): 263–291.
[4] EFSA. Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs. April 2023. EFSA Journal Volume21, Issue4