Paper based immunocapture for targeted protein analysis

A novel sampling concept for mass spectrometric bottom-up targeted protein analysis is here demonstrated with polymeric sampling spots integrated with instant immunocapture for analysis of dried matrix spots. The polymers 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) and pHEMA-Tosyl for covalent attachment of antibodies where investigated alongside with adsorption on non-treated filter paper. From performance characterization, the pHEMA-VDM had the best performance. The sampling spots demonstrated fast and easy sampling and preparation of human serum spiked with the biomarker human chorionic gonadotropin. The sampling spots enabled a detection limit of 1 ng/mL (26.4 pM) within a five point concentration curve from 1 ng/mL to 20 ng/mL (R² = 0.97). The detection limit was demonstrated to be two times lower than previously demonstrated with standard …