Method for the simultaneous determination of arsenic, aluminium, iron, zinc, chromium and copper in plant tissue without the use of perchloric acid

Abstract

A 0.5-g sample of plant tissue was digested with a mixture of concentrated nitric and sulphuric acids (2 + 1 V/V) and hydrogen peroxide. Arsenic was determined by the hydride generation method. Aluminium, iron, zinc, chromium and copper were determined by direct flame atomic-absorption spectrometry. The detection limits in dry plant material using 50 ml of aqueous solutions for analysis were 0.5 ng g^–1 for arsenic and 0.1 µg g^–1 for aluminium, iron, zinc, chromium and copper. The relative standard deviations were 4, 6, 1, 11, 6 and 7%, respectively. All six metals were determined from the same aliquot with recoveries ranging from 93 to 118%. A study was made of the composition of the precipitate that settled out from the extracts. X-ray diffraction revealed the presence of α-aluminium oxide (corundum) and some quartz in the anti-bumping granules. α-Aluminium oxide was a source of contamination for the aluminium analysis.