Immuno-enriched microsphere - magnetic blade spray tandem mass spectrometry or domoic acid in mussels

Samenvatting

Paramagnetic microspheres can be used in planar array fluorescence immunoassays for single or multiplex screening of food contaminants. However, no confirmation of the molecular identity is obtained. Coated Blade Spray (CBS) is a direct ionization mass spectrometry (MS) technique; however, its inherent lack of chromatography compromises the specificity of the measurement for
unequivocal identification of contaminants, based on the European Union (EU) regulation.
Therefore, a rapid and easy-to-use immuno-magnetic blade spray (iMBS) method was developed, in which immuno-enriched paramagnetic microspheres replace the coating of CBS. The iMBS-MS/MS was fully optimized, validated in-house following the EU 2021/808 regulation, and benchmarked against a commercial lateral flow immunoassay (LFIA) for on-site screening of domoic acid (DA). The applicability of the iMBS-MS/MS was further demonstrated by analyzing incurred mussel samples.
The combination of immunorecognition and MS/MS detection in iMBS-MS/MS enhances the measurement's selectivity, which is demonstrated by the differentiation between the marine toxin DA and its structural analog kainic acid, which cannot be achieved with the LFIA alone. Interestingly, this first ever reported iMBS-MS/MS method is generic, and can be adapted to include any other immuno-captured food contaminant, provided antibodies are available, thus offering a complementary confirmatory analysis approach to multiplex immunoassay screening methods.