Proposed methods for determination of As, Cd, Cr(III), Cr(VI), Hg, Ni, Pb and Se in mineral fertilizers by AAS and ICP OES

Abstract

The main objective of this research project is the development of methods for the determination of As, Cd, Cr(III) Cr(VI), Hg, Ni, Pb and Se in mineral fertilizers by graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma optical emission spectrometry (ICP OES). A systematic study of different sample preparation methods will be done, such as: extraction using microwave oven with closed vessel system, extraction using conventional heating with closed vessel system and extraction using ultrasonic bath. The heating program of microwave oven, the energy and time of sonication, particle size and the conditions for AAS and ICP OES operation are some of the parameters to be studied. Two reference materials (Trace elements in multi-nutrient fertilizer - SEMÒ (695) and SEM 120c - Phosphate rock (florida) of the National Institute of Standards & Technology will be used for optimization and to evaluate the accuracy of the proposed methods. Speciation of Cr(III) and Cr(VI) will be evaluated using alkaline extractors for Cr(VI) and determination by GF AAS and UV-vis Spectrophotometry. (AU)