Determination of Selenium in Animal Feed Premix by Atomic Absorption Spectroscopy

Abstract

Abstract An atomic absorption spectrophotometry method for the determination of selenium in animal feed premixes is described. The method involves digesting the samples by heating with perchloric acid and hydrogen peroxide. No pre-concentration or separation is required other than filtering the insoluble material remaining after digestion. Concentrations from 0.0057 to 0.42% selenium were measured. The relative standard deviation over this range averaged 4.6%. A matrix effect, which could be overcome by either preparing the standards with a matrix or using the standard addition technique, was noted at ≤0.02% selenium. The results obtained by each method and by x-ray fluorescence are shown and compared with the claimed selenium content. When the matrix effect is overcome, results by atomic absorption spectroscopy and x-ray fluorescence agree within 15% or better at all levels.