Low-temperature electrothermal vaporization of refractory elements as 8-hydroxyquinolinate complexes in inductively coupled plasma atomic emission spectrometry. Part 2. Determination of trace amounts of chromium in aluminium alloy and rock samples

Abstract

A method, based on low-temperature vaporization of an 8-hydroxyquinolinate complex from a tungsten boat cuvette, is proposed for introducing trace amounts of chromium present in a digested aluminium alloy and rock samples into an inductively coupled plasma for atomic emission spectrometric detection. The operating conditions were optimized and the effect of foreign ions was investigated. Aluminium ions were found to improve the sensitivity and precision of the proposed method. The presence of aluminium ions in the sample solutions was also effective in suppressing the interferences from other foreign ions. The detection limit in the presence of 2.5 µg of aluminium (III) was determined to be 0.05 ng of chromium and that in the absence of aluminium (III), 0.07 ng. The precisions as relative standard deviation (RSD%) for 2.5 ng of chromium under the conditions described above were 2.2 and 4.6%(n=6), respectively. The chromium contents in some standard materials and reference samples determined by the proposed method were in good agreement with the certified or reference values.