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In this paper, magnetic molecularly imprinted nano-conjugates were synthesized to serve as selective sorbents in a model study of tyramine determination in craft beer samples. The molecularly imprinted sorbent was characterized in terms of morphology, structure, and composition. The magnetic dispersive solid phase extraction protocol was developed and combined with liquid chromatography coupled with mass spectrometry to determine tyramine. Ten samples of craft beers were analyzed using a validated method, revealing tyramine concentrations in the range between 0.303 and 126.5 mg L -1 . Tyramine limits of detection and quantification were 0.033 mg L -1 and 0.075 mg L -1 , respectively. Therefore, the fabricated molecularly imprinted magnetic nano-conjugates with a fast magnetic responsivity and desirable adsorption performance could be an effective tool for monitoring tyramine levels in beverages.

This article is part of a series devoted to discussing strategies for the synthesis of ion-imprinted polymers and molecularly imprinted polymers, their chemical structure and great potential, which may be used in porous material design, analytical chemistry, environmental protection and other areas of science. The presented work constitutes a basis for a better understanding of what porous polymers are, how we can synthesise them and how to foresee their properties, which can be later used in studies of environmental pollution and analytical chemistry. [ABSTRACT FROM AUTHOR]

In this paper the exploration of specific imprinted sorbent for 4-hydroxy-3-nitrophenylacetic acid (NHPA), an indicator of 3-nitrotyrosine, a biomarker of pathophysiological states, was described. The optimization of synthetic protocol, supported by theoretical studies, allowed to select NHPA imprinted poly(acrylic acid- co -ethylene glycol dimethacrylate) as the most specific polymer with imprinting factor equal to 2.27. The acrylic copolymers were characterized, revealing differences between the imprinted and non-imprinted material in the adsorption binding capacities (0.54 ± 0.12 and 0.335 ± 0.073 μmol g−1, respectively), heterogeneity indices (0.47 and 0.72), pseudo-second order kinetics constants (0.251 and 0.077 g μmol −1 min−1, respectively), and total specific surface areas (51.8 and 292.3 m2 g−1, respectively). The significant difference in the microstructure of pores was considered as the crucial factor responsible for sorption properties of analyzed materials. • 4-Hydroxy-3-nitrophenylacetic acid imprinted polymer was investigated. • Synthesis optimization supported by theoretical analysis was carried out. • Insight into morphology and sorption properties of sorbent was provided. • Imprinted poly(acrylic acid- co -ethylene glycol dimethacrylate) porosity was analyzed. • Extraction capabilities from model multicomponent sample were analyzed. [ABSTRACT FROM AUTHOR]