Aptamer-functionalized stir bar sorptive extraction for selective isolation, identification, and determination of concanavalin A in food by MALDI-TOF-MS

• Published in: Mikrochimica acta (1966) 2023-06, Vol.190 (6), p.219-219, Article 219
• Main Authors: Vergara-Barberán, María, Catalá-Icardo, Mónica, Simó-Alfonso, Ernesto F., Benavente, Fernando, Herrero-Martínez, José Manuel
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Beans; Characterization and Evaluation of Materials; Chemical synthesis; Chemistry; Chemistry and Materials Science; Chickpeas; Concanavalin A; Food; Ionization; Ions; Lectins; Lentils; Mass spectrometry; Microengineering; Nanochemistry; Nanotechnology; Oligonucleotides; Original Paper; Peptides; Polytetrafluoroethylene; Proteins; Sorbents; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Thiols
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-023-05795-y

An aptamer-functionalized stir bar sorptive extraction (SBSE) coating is described for the first time devoted to selective isolation and preconcentration of an allergenic food protein, concavanalin A (Con A), followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF-MS) determination. For this purpose, the polytetrafluoroethylene surface of commercial magnetic stir bars was properly modified and vinylized to immobilize a thiol-modified aptamer against Con A via straightforward “thiol-ene” click chemistry. The aptamer-functionalized stir bar was employed as SBSE sorbent to isolate Con A, and several parameters that can affect the extraction efficiency were investigated. Under the optimized conditions, Con A was extracted and desorbed during 30 and 45 min, respectively, at 25 °C and 600 rpm. The SBSE MALDI-TOF-MS method provided limits of detection of 0.5 μg mL −1 for Con A. Furthermore, the SBSE coating was highly selective to Con A compared to other lectins. The developed method was successfully applied to the determination of low levels of Con A in several food matrices (i.e., white beans as well as chickpea, lentils, and wheat flours). Recoveries ranged from 81 to 97% with relative standard deviations below 7%. The aptamer-based stir bars presented suitable physical and chemical long-term stability (1 month) and a reusability of 10 and 5 extraction cycles with standards and food extracts, respectively. The developed aptamer-affinity extraction devices open up the possibility of developing novel highly selective SBSE coatings for the extraction of proteins and peptides from complex samples. Graphical abstract