Application of a Custom-Synthesized Molecularly Imprinted Polymer for the Selective Isolation of Total Glucose and Fructose from 100% Fruit Juice Samples Prior to Instrumental Analysis

Abstract

This article presents a novel sample preparation strategy that employed a custom-synthesized glucose - fructose (G-F) specific molecularly imprinted polymer (MIP) powder as an adsorbent for the simultaneous and selective extraction, isolation and pre-concentration of total glucose and fructose from the complex and `dirty` sample matrix of ‘100%’ fruit juices purchased from retail shops in Palapye, Botswana. The prepared G-F MIP powder demonstrated high selectivity, effective extraction and isolation for glucose and fructose from real samples of `100%` fruit juice samples as evidenced by the calculated high extraction efficiencies (EEs) of over 90%, with low percentage relative standard deviations (%RSD) of below 7% for n=6, for both glucose and fructose when compared to the low EEs of below 25% by the non-imprinted polymer (NIP), regarded as the control. Furthermore, the G-F MIP showed lower selectivity towards the analogous molecules; maltose and lactose as supported by the low EEs of below 31%. With the high affinity for glucose and fructose, the selective sample preparation strategy proposed herein presented itself as a potential procedure to be employed to improve the accurate analysis of adulterated artificial sugar sweeteners that are usually illegally added to the so-called `100%` fruit juices by producers to improve their taste.