Molecularly Imprinted Polymer for a Smart Dispersive Micro-Solid Phase Extraction Technique for Assessing Trace Level Aflatoxins in Cultured Fish

Abstract

Molecularly imprinted technology (MIT) consists of preparing materials exhibiting specific recognition cavities to selective mimic the target analytes. The prepared materials promote selective interactions with the targets and avoid interactions of concomitants from complex food, biological, clinical, and environmental matrices. This chapter provides information on a recent development of a vortex-assisted micro-solid phase extraction using a molecularly imprinted polymer (MIP) as an adsorbent for aflatoxins (AFs) determination in cultured fish. MIP particles were synthesized by precipitation polymerization using 5,7-dimethoxycoumarin as a dummy template, methacrylic acid as a functional monomer, divinylbenzene as a cross-linker, and 2,2-azobisisobutyronitrile as an initiator. Polymerization following the precipitation method guarantees homogeneous particle size distribution and the integrity of the imprinted cavities. The MIP microparticles were found to have 5 μm in diameter and a spherical shape. Important parameters such as sample extract pH, adsorption stirring speed and time, desorption stirring speed and time, elution solvent composition and volume, and polymer mass, were fully optimized. The pre-concentration method allows therefore the assessment of four major AFs (B1, B2, G1, and G2) present in cultured fish at very low levels, with pre-concentration factors from 15 to 50 depending of the volume of extract used for performing the dispersive micro-solid phase extraction (D-μ-SPE).

Keywords: Aflatoxins; Cultured fish; Dispersive micro-solid phase extraction; Molecularly imprinted polymers; Precipitation polymerization.