On-fiber furan formation from volatile precursors: a critical example of artefact formation during Solid-Phase Microextraction

For the analysis of furan, a possible carcinogen formed during thermal treatment of food, Solid-Phase Microextraction (SPME) is a preferred and validated sampling method. However, when volatile furan precursors are adsorbed on the carboxen/PDMS fiber, additional amounts of furan can be formed on the fiber during thermal desorption, as shown here for 2-butenal and furfural. No significant increase in furan amounts was found upon heating the furan precursor 2-butenal, indicating that the furan amounts formed during precursor heating experiments are negligible as compared to the additional amounts of furan formed during fiber desorption. This artefactual furan formation increased with increasing desorption time, but especially with increasing desorption temperature. Although this effect was most pronounced on the Carboxen/PDMS SPME-fiber, it was also noted on two other SPME-fibers tested (PDMS and DVB/Carboxen/PDMS). The general impact on furan data from food and model systems in literature will depend on the amounts of volatile precursors present, but will probably remain limited. However, considering the importance of this worldwide food contaminant, special care has to be taken during SPME-analysis of furan. Especially when performing precursor studies, static headspace sampling should preferably be applied for furan analysis.