The use of direct sample insertion into a nitrogen-argon inductively coupled plasma for emission spectrometry-I: Technique optimization and application to the analysis of aluminium oxide

Abstract

The determination of trace elements in aluminium oxide with the aid of direct sample insertion inductively coupled plasma atomic emission spectrometry (ICP-AES) has been studied. The form and shape of the graphite cups containing the sample as well as the gas flows and other ICP parameters were optimized with dry solution residues containing zinc, copper and strontium. It was found that after mixing the aluminium oxide in the proportion 1:1 with graphite powder and briquetting pellets of 10–20 mg, relatively volatile elements such as Cd, Cu, Mg and Zn could be volatilized and detected down to the μg g level. For titanium, which forms refractory carbides, the effect of different volatilization aids (NH 4C1, AgCl, BaF 2 and PTFE) has been studied. With addition of PTFE quantitative determinations are possible and a detection limit of 7 μg g is obtained. Relative standard deviations in the case of peak areas obtained from time-resolved and simultaneous measurements of line and background intensities are at the order of 5 % and the calibration curves are linear over at least one order of magnitude.