An Overview of Conventional and Emerging Analytical Methods for the Determination of Mycotoxins

Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results

Development of an electrochemical immunosensor for fumonisins detection in foods

An electrochemical affinity sensor for the determination of fumonisins mycotoxins (Fms) using monoclonal antibody modified screen-printed gold electrode with carbon counter and silver-silver chloride pseudo-reference electrode is reported in this work. A direct competitive enzyme-linked immunosorbent assay (ELISA) was initially developed, exhibiting a detection limit of 100 µg·L-1for fumonisins. This was then transferred to the surface of a bare gold screen-printed electrode (SPGE) and detection was performed by chronoamperometry, monitoring the reaction of 3,3',5,5'-Tetramethylbenzidine dihydrochloride (TMB) and hydrogen peroxide (H2O2) catalysed by HRP at -100 mV potential vs. onboard Ag-AgCl pseudo-reference electrode. The immunosensor exhibited detection limit of 5 µg·L-1 fumonisins with a dynamic range from 1 µg·L-1-1000 µg·L-1. The sensor also performed well in extracted cor

Electrochemical immunosensor for determination of aflatoxin B1 in barley

This paper reports the assembly of a disposable electrochemical immunosensor based on the indirect competitive enzyme linked immunosorbent assay (ELISA), for simple and fast measurement of aflatoxin B1 (AFB 1) in barley using differential pulse voltammetry (DPV). The immunosensor strip was assembled immobilising the biological component (i.e. the AFB1 conjugated to bovine serum albumin, incubation the sample (or standard) with the monoclonal antibody anti-AFB1 (MAb). A spectrophotometric ELISA was used in a preliminary phase of development, prior to transferring the assay to the SPEs. Results showed a detection limit of 20 and 30 pg/mL for the spectrophotometric ELISA and the electrochemical immunosensor, respectively. The extraction efficiency and the matrix effect have been evaluated by spiking blank barley with AFB1 before and after the sample treatment. After treatment, samples were analysed using a 1:10 (v/v) dilution in PBS (phosphate-buffered saline, pH 7.4) in order to minimise the matrix effect. Good recoveries were obtained, which demonstrated the suitability of the proposed method for routine screening of AFB1 in barley. © 2004 Elsevier B.V. All rights reserved

Detection of aflatoxin B-1 in barley: Comparative study of immunosensor and HPLC

In the present work, an indirect competitive electrochemical enzyme linked immunosorbent assay (ELISA) has been used for determination of aflatoxin B 1 (AFB 1) in barley. The method involves the use of disposable screen-printed carbon electrodes (SPCEs) and anti-aflatoxin B 1 monoclonal antibodies (MAb) for immunosensor development. The specificity of the assay was assessed by studying the cross-reactivity of the MAb relative to AFB 1 . The results indicated that the MAb could readily distinguish AFB 1 from other toxins, with the exception of AFG 1 . The stability of the coating reagents was evaluated using SPCEs coated with AFB 1-bovine serum albumin (BSA) conjugate. The results showed that the coated electrodes could be used for up to one month after their preparation and storage at 4 degrees C. Prior to evaluating the performance of the electrochemical immunosensor for AFB 1 with spiked samples, the effect of barley extract on assay performance was tested. Using this calibration method, the limit of detection (LOD) was found to be 90 pg mL(-1) . The linear range was 0.1-10 ng mL(-1) , and recoveries ranged from 100%-125%. The results obtained were confirmed by high performance liquid chromatography (HPLC) coupled with fluorescence detection. These results demonstrated the suitability of the proposed method for routine screening of AFB 1 in barley