Assessment of bisphenol A and bisphenol B in canned vegetables and fruits by gas chromatography-mass spectrometry after QuEChERS and dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction (DLLME) combined with an acetonitrile based extraction was proposed for simultaneous extraction, concentration and derivatization of bisphenol A (BPA) and bisphenol B (BPB) in canned vegetables and fruits prior to gas chromatography-mass spectrometry (GC-MS) analysis. The DLLME procedure involved the use of tetrachloroethylene as extractive solvent while, the own acetonitrile extract obtained from QuEChERS was used as dispersive solvent, and anhydride acetic as derivatizing reagent. Besides the enrichment factor provided, the final DLLME extractive step allowed the simultaneous acetylation of the compounds required for their GC analysis. The validated method showed to be accurate (>69% recovery), reproducible (<20% relative standard deviation) and sensitive for the target analytes (method detection limits of 0.3 μg/kg and 0.6 μg/kg for BPA and BPB, respectively). The screening of several canned vegetables and fruits commercialized in Portugal revealed the presence of BPA in more than 87% of the samples with levels ranging from 3.7 to 265.6 μg/kg, while BPB was detected in only two samples, one canned fruit and one canned vegetable with levels of 3.4 μg/kg and 3.0 μg/kg, respectively. Some factors that may determine these results, as type matrix, origin and expiration data were evaluated. Lower levels of BPA were detected in canned fruits than in canned vegetables.