Eu(III)-Templated molecularly imprinted polymer used as a luminescent sensor for the determination of tenuazonic acid mycotoxin in food samples

Abstract

Tenuazonic acid (TeA) is a common mycotoxin produced by Alternaria species found in various foodstuffs. Herein, we describe the preparation of porous molecularly imprinted polymer (MIP) microspheres doped with Eu(III), for selective fast analysis of TeA in rice extracts. The TeA template, bearing a β-diketone moiety, is a good Eu(III)-chelating antenna ligand that can be selectively captured in the MIP cavities and detected by observing the “turned-on” sensitized luminescence of the Eu(III) ions at 615 nm (λex 337 nm). A MIP library was prepared at small scale using diethyl allylmalonate (DEAM) or allyl acetoacetate as functional monomers, mixed in different mole ratios with the template and ethylene glycol dimethacrylate (EDMA) as cross-linker. The screening allowed selection of poly(DEAM-co-EDMA) with Eu(III) as luminogenic metal center for the sensor development. Under the optimized conditions, a linear response to TeA in the 1.7–20 μg mL−1 range, with a detection limit of 0.5 μg mL−1, was obtained. The Eu(III)-doped MIP for TeA showed very little or no cross-recognition of other mycotoxins present in foodstuff such as alternariol, β-zearalenol and cyclopiazonic acid, even containing the same recognition moiety. The MIP-based optosensor was successfully applied to the analysis of rice extracts spiked with TeA, and the results were confirmed by HPLC-DAD.