Dissolve exactly 10g sample in distilled water and add 30 ml conc. hydrochloric acid. Heat the solution up to 80-90°C and add small portions off hydrazinium sulphate until no more precipitation of red elemental Selenium can be observed. Heat the solution for two more hours to allow the Selenium the complete transformation into the grey form. Suck off the solution through a weighed filter crucible, wash the residue with hot, distilled water until acid free, dry and weigh. The weight multiplied with 10 gives the Selenium content of the sample in percent.

Moisture:
Dry a weighed sample for 3 hours at 120°C and weigh again. The weight difference multiplied with 100 and divided by the original weight gives the moisture content in percent.