Abstract
PECULIARITIES OF SAMPLE PREPARATION FOR THE DETERMINATION OF CERTAIN MYCOTOXINS IN GRAIN PRODUCTS AND FRUITS BY IMMUNOBIOSENSOR ANALYSIS
Dr. N. F. Starodub*, M. V. Savchuk, A. Székács, J. L. Marty
ABSTRACT
Our current report focuses on effective ways of sample preparation fordetection of mycotoxins aflatoxin B1 and T2 in grain products (wheat,maize, sunflower and oats) as well as patulin in fruits (plum, apple andgrape) by the surface plasmon resonance (SPR) immunobiosensor. Aneffective method for carrying out analysis of mycotoxins by an SPR Immunobiosensor wasassessed, and the results obtained were compared with those determined in a traditionalELISA method. The analysis with the immunobiosensor is capable to be carried out in adirect format on the basis of mycotoxin-specific antibodies immobilized on the sensorsurface, but its sensitivity was found to be lower than that obtained in a competitive formaton the basis of an immobilized mycotoxin conjugate. Due to this characteristic difference inanalytical sensitivity, we recommend the former format for screening for the presence ofmycotoxins in environmental samples. In turn, the latter format is proposed for verification ofthe obtained results of analysis. The competitive analysis by the immunobiosensor hasdemonstrated sensitivity in the range of the traditional ELISA method. Organic solventextraction of the three mycotoxins, aflatoxin B1, T2 and patulin from produce samples wascarried out with acetonitrile and methanol, and the former solvent was concluded thatpreferable. Particular attention was paid to the problem of matrix components detrimentallyaffecting extractability and the immunochemical reaction: difficulties due to the presence of small quantities of vegetable oil in grain products needed to be overcome. In cases of samples of substantial vegetable oil content, acetone as an extraction solvent is recommended, the use of which did not appear to affect immunoanalysis results. It was demonstrated that the analysis of patulin in fruits depends on pH of the obtained samples, especially if mycotoxin content is determined in an unripe stage. In such cases, pH determination and neutralization by a special buffer prior to immunoanalytical measurements are recommended
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