COMPARISON OF DRY ASHING AND WET ACID DIGESTION ON THE DETERMINATION OF BORON IN PLANT-TISSUE

Dry ashing and wet acid digestion of selected plant tissues were conducted and evaluated for their effectiveness in the spectrophotometric determination of boron (B) using the Azomethine-H method. In dry ashing, two parameters were varied: ashing aids and length of oxidation period. In wet acid digestion, two different mineral acids were used and the length of the oxidation period was varied between 12 and 24 h. Results showed that samples treated with sulfuric acid in dry ashing had the lowest recoveries of B. Boron concentrations in tissues oxidized for 12 h in wet acid digestions were at least 40% higher than the results obtained for any dry ashing technique.