Immuno-Enriched Microspheres - Magnetic Blade Spray-Tandem Mass Spectrometry for Domoic Acid in Mussels

Abstract

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, and when combined with triple quadrupole MS/MS, it allows for rapid confirmation of food contaminants. The lack of chromatography in CBS, though, 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 method 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 DA. The applicability of 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 rapid differentiation between the marine toxin domoic acid (DA) and its structural analog kainic acid (KA), 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 that monoclonal antibodies are available, thus offering a complementary confirmatory analysis approach to multiplex immunoassay screening methods. Moreover, thanks to its speed of analysis, iMBS-MS/MS can bridge the logistics gap between future large-scale on-site testings using LFIAs and classical time-consuming confirmatory MS analysis performed in official control laboratories.

Applications of ambient ionization mass spectrometry in 2021: An annual review

“…Using multivariate analysis, fresh and frozen‐thawed samples could be rapidly differentiated with an accuracy of 92–100%, with discrimination primarily based on changes in the content of fatty acids and phospholipids (Figure 3). Various AIMS techniques have also been utilized to detect the presence of toxins in food products, such as LAESI to detect mycotoxins in mold‐infected fruit, 91 DART‐MS coupled with a smartphone‐based lateral flow to detect mycotoxin contamination 92 and immuno‐magnetic blade spray (a coated blade spray‐based technique) to detect the marine toxin domoic acid 93 …”

Understanding the effect of spatial positioning of coated blade spray devices relative to the mass spectrometry inlet on different instrument platforms and its application to quantitative analysis of fentanyl and related analogs

“…Since its inception in 2014, coated‐blade spray (CBS) – a technology that combines microextraction and ambient ionization in a single device – has demonstrated its suitability and robustness for a variety of analytical applications, including environmental and bioanalytical studies 6,8,20–29 . Conceptually, CBS consists of a small stainless‐steel blade coated with a polymeric sorbent.…”

“…15,[17][18][19] Since its inception in 2014, coated-blade spray (CBS)a technology that combines microextraction and ambient ionization in a single devicehas demonstrated its suitability and robustness for a variety of analytical applications, including environmental and bioanalytical studies. 6,8,[20][21][22][23][24][25][26][27][28][29] Conceptually, CBS consists of a small stainless-steel blade coated with a polymeric sorbent. Ideally, the deposited particles are between 1 and 10 μm in diameter to ensure rapid analyte-enrichment/analyte-elution from the coating.…”

Immunoaffinity Plastic Blade Spray Mass Spectrometry for Rapid Confirmatory Analysis of Food Contaminants

“…14,15 The latest development combines CBS with antibody enrichment in the developed immuno-enriched paramagnetic microspheres− magnetic blade spray (iMBS), in which the coating of the blades has been replaced by mAbs-enriched paramagnetic microspheres, held on the blade by a magnet. 16 This method has demonstrated the added specificity and selectivity in the direct MS/MS analysis of analytes in complex sample matrices. However, the paramagnetic microspheres and the magnet increase the cost and complexity of the analysis: iMBS requires a rather extensive protocol for microsphere and blade preparation based on a covalent immobilization protocol entailing an EDC/NHS amine coupling procedure.…”

“…To counterbalance the lack of chromatographic separation, antibodies have been employed for specific extraction/separation of the targeted analyte, followed by ambient or direct ionization and fast MS identification. , The latest development combines CBS with antibody enrichment in the developed immuno-enriched paramagnetic microspheres–magnetic blade spray (iMBS), in which the coating of the blades has been replaced by mAbs-enriched paramagnetic microspheres, held on the blade by a magnet . This method has demonstrated the added specificity and selectivity in the direct MS/MS analysis of analytes in complex sample matrices.…”