Synthesis and application of a T-2 toxin imprinted polymer

Abstract

The synthesis of a T-2 toxin imprinted polymer and its application in food analysis are reported for the first time. A molecularly imprinted polymer (MIP) for the selective recognition of T-2 toxin (T-2) was synthesized by bulk polymerization. Methacrylamide and ethyleneglycol dimethacrylate were applied as functional monomer and cross-linker, respectively. Molecularly imprinted solid-phase extraction (MISPE) procedures were optimized for further application in the analysis of T-2. Scatchard plot analysis revealed that two classes of imprinted binding sites were formed in the imprinted polymer. The dissociation constant ( K D) of the higher affinity binding sites was 7.0 μmol/l, while the K D of the lower affinity binding sites was 54.7 μmol/l. The performance of the MIP throughout the clean-up of spiked maize, barley and oat sample extracts was compared with the results obtained when using non-imprinted polymer, OASIS HLB ® and immunoaffinity columns (IAC). Depending on the food matrix and the spiked concentration, recoveries after MISPE and non-imprinted solid-phase extraction varied respectively from 60% to 73% and from 21% to 57%. Recoveries obtained after clean-up using OASIS HLB ® and IAC were in the range of 74–104% and 60–85%, respectively. Although highest recoveries were obtained with OASIS HLB ® sorbents, the designed MIP and the IAC were superior regarding selectivity, cross-reactivity, matrix effect, limits of detection (LOD) and limits of quantification (LOQ). Depending on the matrix, LOD after MISPE ranged from 0.4 μg/kg to 0.6 μg/kg and LOQ from 1.4 μg/kg to 1.9 μg/kg. LOD and LOQ after OASIS HLB ® clean-up varied from 0.9 μg/kg to 3.5 μg/kg and from 3.1 μg/kg to 11.7 μg/kg, respectively. The LOD and LOQ values obtained with IAC were in the range of 0.3–2.3 μg/kg and 1.0–7.7 μg/kg, respectively. Analysis of 39 naturally contaminated samples (maize, barley and oat) by liquid chromatography tandem mass spectrometry revealed that the MIP could be an excellent alternative for clean-up of contaminated food samples.