Optimization of the determination of deoxynivalenol in corn samples by liquid chromatography and a comparison of two clean-up principles

The determination of deoxynivalenol (DON) in corn by liquid chromatography with DAD detection was optimized. The separations were achieved on a Hypersil ODS column (100 x 4.6 mm; particle size 5 μm) by isocratic elution (0.6 cm 3 /min), a mobile phase consisting of acetonitrile-water in the ratio of 16:84. UV Detection was performed at 220 nm. Linear calibration curves were constructed in the concentration range of 0.72 - 12.00 ng/μl (equivalent to 0.29 - 4.8 μg/g corn). The detection limit measured as the signal-to-noise ratio (3:1) was 0.16 ng/μl for DON (equivalent to 0.06 μg/g corn). The efficiencies of two clean-up principles for crude corn extract were compared: solid-phase and immunochemical extraction. The efficiency of solid-phase extraction was found to be higher, with a value of 92.7 % when MycoSep 225 columns were used, while its value was 97.6 % when self-made activated charcoal-alumina-Celite-cationic columns were used. In contrast, the efficiency of the immunochemical columns (IMA) was only 73.8 %. It was also found that the self-made columns could be used at least three times in a row, in that way differing from the MycoSep 225 columns, which could not be reused either with or without regeneration, as well as from the IMA columns, which had a regeneration efficiency of 53.6 %.