Quantitation of benzene in flavourings and liquid foods containing added cherry-type flavour by a careful work-up procedure followed by a stable isotope dilution assay
The exposure of humans to the aromatic hydrocarbon benzene should be minimized due to its carcinogenicity. Previous studies have reported on the presence of benzene, in particular in foods with added cherry aroma compounds, in particular benzaldehyde. To allow a reliable quantitation of benzene, a stable isotope dilution assay using (2H3)benzene as the internal standard was developed and solid phase microextraction (SPME) was used for volatile isolation followed by GC × GC–TOFMS analysis. Care was taken to avoid any exposure to light and to use materials during work-up, which were free of benzene contamination. The method, applied on 22 liquid foods with added flavour showed that benzene did not exceed a concentration of 1 µg/L in any sample (i.e. the limit established for drinking water). Furthermore, flavourings containing benzaldehyde and the corresponding raw material were analysed. The major source of benzene in flavourings turned out to be benzaldehyde itself. First insights into parameters supporting the formation pathway of benzene from benzaldehyde were obtained indicating that the presence of light and either acidic or alkaline conditions favoured benzene formation.
KeywordsBenzene quantitation Stable isotope dilution assay Solid phase microextraction Liquid flavoured food Flavouring Light exposure
The authors thank L. Romanski, I. Otte, and S. Kaviani-Nejad for excellent technical assistance.
This research project was supported by the German Ministry of Economics and Energy (via AiF) and the FEI (Forschungskreis der Ernährungsindustrie e.V., Bonn). Project AiF 18813 N.
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Conflict of interest
The authors declare that they have no conflict of interest.
Compliance with ethics requirements
This article does not contain any studies with human or animal subjects.
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