DETERMINING SELENIUM IN PLANT-TISSUE WITH OPTIMAL DIGESTION CONDITIONS

A procedure is described for optimizing plant tissue digestion conditions for accurate selenium (Se) analysis. Optimal concentrations of nitric acid, ceric ammonium nitrate, hydroxylamine HC1 and the use of vapor trapping funnel were evaluated for total recovery of Se in NIST wheat flour reference material using atomic absorption spectrophotometry with continuous Se hydride generation. During sample digestion, excessive or insufficient amounts of nitric acid (<0.45 M or >1.02 M), ceric ammonium nitrate (<6.7 x 10-5M or >6.6 x 10–4 M), or hydroxylamine HC1 (<0.016 M or >0.398 M) caused a 15-20% reduction in the total Se recovered. Additional losses up to 15% were observed in the same samples without the use of the vapor trapping funnel. These results demonstrated how digestion conditions must be optimized for precise and accurate Se analysis in plant tissue. © 1990, Taylor & Francis Group, LLC. All rights reserved.