DETERMINATION OF SELENIUM IN SOIL BY CONTINUOUS HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

A method is developed to determine plant-assimilable selenium in soil, based on reducing the selenium with sodium tetrahydroborate and introducing the gaseous hydride into a low power inductively Coupled Plasma without altering its stability. The experimental procedure involves continuously reacting the selenium sample in 3M HCl at a flow rate of 6 mL.min-1, and a 2 mL.min-1 flow rate of (1% w/v) sodium tetrahydroborate reductant solution. The analytical performances obtained are as follows: detection limit is 0.80 ng.mL-1; a dynamic range from 6.0 to 2000 ng.mL-1 and a relative standard deviation of 4.05% is found for a concentration of 100 ng.mL-1.