Development of an aflatoxin B1 specific molecularly imprinted solid phase extraction sorbent for the selective pre-concentration of toxic aflatoxin B1 from child weaning food, Tsabana

Abstract

In this thesis, the synthesis, optimization and application of a simple aflatoxin B1 (AFB1) specific extraction polymer sorbent based on molecular imprinting technology (MIT), for the selective pre-concentration of the potent AFB1 toxin from child weaning food, Tsabana manufactured in Serowe, Botswana is presented. As a food safety regulatory measure, the Tsabana must be cleared of the hazardous aflatoxins especially AFB1 before consumption as it is the most potent amongst those commonly found in cereals. Accurate analysis of AFB1 is a challenge as AFB1 exists in complex, ‘dirty’ matrices such as that of food in very low concentrations thus making it difficult for the existing analytical instruments to detect it despite their femto level sensitivities. The synthesized molecularly imprinted solid phase extraction sorbent in this thesis, managed to deal with the challenge by selectively pre-concentrating the AFB1 from real samples of Tsabana extracts by a pre-concentration factor of 5, thus the signal was greatly improved for easy detection. This was further supported by the short optimal time of 25.0 minutes needed for the maximum AFB1 extraction by the sorbent as well as the reasonable optimal dose of the MIP, 20.0 mg needed for maximum extraction of AFB1. The prepared AFB1 powder particles also exhibited good physical characteristics of a spherical geometry and reasonably small sizes of 800 nm associated with excellent sorbent materials, as demonstrated by the scanning electron micrographs.