Polymeric sorbents modified with gold and silver nanoparticles for solid-phase extraction of proteins followed by MALDI-TOF analysis

The authors describe four different kinds of sorbents for solid-phase extraction (SPE) and preconcentration of proteins from complex samples. All are based on the use of a poly(glycidyl-co-ethylene dimethacrylate) host monolith that was chemically functionalized by using two different ligands (ammonia and cysteamine). Gold nanoparticles (AuNPs) or silver NPs were then assembled to the amino or thiol groups. The resulting materials are shown to be viable stationary phases for use in SPE cartridges. The sorbents can selectively retain bovine serum albumin, and the thiol-modified sorbents containing AuNPs and AgNPs provide the highest recoveries (>90%) and satisfactory loading capacities (29.3 and 17.6 μg⋅mg−1 of sorbent, respectively). The applicability of these nanosorbents was demonstrated by preconcentrating viscotoxins from mistletoe extracts. The enriched fractions were subjected to MALDI-TOF analysis to underpin their selectivity.