In order to facilitate a practical large-scale introduction of the radioimmunochemical control of aflatoxin B1 contamination in cereals and feeds a new method of the preparation of sample extracts was verified. In comparison with the procedure used until now when water-nonmiscible chloroform must be evaporated from a chloroform extract and the solids must be dissolved in acetone, while using the tested method the sample is extracted by methyl alcohol or acetone and the extract is diluted by a buffer before the radioimmunoanalysis. This new method of sample extract preparation displays aflatoxin B1 recovery comparable to that of the older method (83-90% for concentrations of 2-20 micrograms per kg), the worse theoretical detection limit (1 microgram per kg vs. 0.2 microgram per kg) but it prevents the result distortion by interfering substances and it makes the whole analytical procedure simpler and expeditious. Radioimmunochemically aflatoxin was quantified by means of commercially produced analytical kits developed in one institute at Kosice.

Vysoká skola chemicko technologická Praha