A modified fluorimetric method for determination of selenium
A modified fluorometric method for determination of selenium content in food and other biological materials using autoclave mineralization of samples has been proposed. Concentrated nitric acid and 50% hydrogen peroxide in a ratio of 6:1 was used as an oxidizing mixture. It has been shown that the optimum conditions for the condensation reaction between selenous acid and 2,3-diaminonaphtalene are as follows: pH 1.8-2.0, temperature 40-50 °C, reaction time 30 minutes. Cyclohexane is the most suitable organic solvent for 4,5-piazoselenol. The developed method improves the accuracy of the selenium determination, reduces the mineralization time of the organic part of the sample, and also excludes the use of hazardous perchloric acid.