Advantages and drawbacks of immunoaffinity columns in analysis of mycotoxins in food

Abstract

A number of countries are setting legislations on mycotoxins. In order to reduce dispute between importing and exporting countries, the analytical data should be as comparable as possible, especially when levels are close to the regulatory limits. The present trend in the analysis of mycotoxins is to use immunoaffinity column (IAC) as a clean-up and enrichment technique, and Association of Official Analytical Chemists and European Union have validated methods which address a few food commodities. This study describes our experience using both conventional and IAC approaches in the analysis of three mycotoxins. Aflatoxins (AFs): Aflatoxin G1 has been detected by liquid-liquid partitioning methods with HPLC detection as false-positive in some maize. On IACs, this compound behaves as an AF, lowering the amount of the AFs trapped. The problem was solved using either TLC or HPLC with detection in the Kobra cell. Depending on the additives to food during the processing and cooking, the AFs might appear as an opened ring not recognised by the antibody. Fumonisins (FB): Compounds interfering with the FB's antibodies were also observed while analysing breakfast cereals leading to underestimation of FB. Ochratoxin A (OTA): Depending on the food composition and extraction techniques, OTA is underestimated with IAC in some breakfast cereals and coffee. These data strengthen the necessity to validate methods using IAC for each complex matrix.

Comparison of ELISA, HPLC-FLD and HPLC-MS/MS Methods for Determination of Aflatoxin M1 in Natural Contaminated Milk Samples

“…This fact could be explained by the possible losses of analyte during the multistage sample preparation such as applied IAC clean up procedure. 44 For that purpose Hongyo et. al, 45 suggested using the same eluted extract to increase the correlation between methods.…”

Preliminary data on the presence of mycotoxins (ochratoxin A, citrinin and aflatoxin B1) in black table olives “Greek style” of Moroccan origin

“…The extraction procedure of these three mycotoxins was accomplished simultaneously by a method using partition developed in our laboratory and then quantified by HPLC [29,30]. The advantage of this method is the simultaneous extraction of the three toxins and avoids the problem of interferences with immunoaffinity column clean up as seen for other foods [29,31]. Moreover, the aim was also to develop a method less expensive than method using immunoaffinity column, suitable in developing countries.…”

Novel Aflatoxin Derivatives and Protein Conjugates

“…as immunogens for the generation of selective polyclonal and monoclonal antibodies against aflatoxins and as protein/enzyme conjugates for enzyme-linked immunosorbent assays (ELISAs). Aflatoxin selective antibodies are needed not only for immunoanalytical screening methods but also for instrumental analysis with immunoaffinity chromatography being a standard cleanup procedure prior to high performance liquid chromatography with fluorescence or mass spectrometric detection [4][5][6]. As aflatoxins, aflatoxin protein conjugates, aflatoxin-selective antibodies, complete ELISA kits for food screening, and immunoaffinity columns for sample cleanup are commercially available by a variety of distributors, the economic importance becomes evident.…”