RAPID METHOD TO DETERMINE SPHINGANINE SPHINGOSINE IN HUMAN AND ANIMALURINE AS A BIOMARKER FOR FUMONISIN EXPOSURE/

The widespread occurrence of fumonisins in maize and maize-based foods and feeds demands the development of rapid and reliable methods for t he analysis of suitable biomarkers in biological fluids in order to as sess human and animal exposure to these important mycotoxins. The incr ease in the ratio of free sphinganine/sphingosine (SA/SO) in urine has been recently proposed as a biomarker to evaluate exposure to fumonis ins. The presently available method for the determination of SA and SO in biological samples is labor intensive, time consuming and insuffic iently accurate. A new method has been proposed for the determination of SA and SO in human and animal urine which is more precise and accur ate, and drastically reduces the number of steps during extraction and clean-up. The method is essentially based on the use of silica minico lumn clean-up of the chloroform extract from alkalinized urine. The fi nal extract is derivatized with o-phthaldialdehyde reagent and SO and SA are determined by reversed-phase HPLC with fluorimetric detector. U rine samples spiked with SO, SA standards at concentrations ranging fr om 1.5 to 15 ng/ml have given mean recoveries higher than 80% and prec ision (coefficient of variation) lower than 10%. Detection limit for S O and SA was 0.1 ng/ml.