Determination of traces of Ni, Co and Fe in Li2CO3/K2CO3 melts by flame atomic absorption spectrometry

A flame atomic absorption spectrometry (AAS) method is described for the de termination of trace levels of Ni, Co, and Fe in 62 mole percent (mol.%) LI 2CO3 and 38 (mol.%) K2CO3 melts after dissolution of the sample in dilute n itric acid. A pneumatic nebulizer with a glass impact bead is used to sampl e introduction. The effect of the high salt loading of the solution on the analytical signals is minimized by optimization of acetylene flow-rate and height of observation above the burner head. Under the optimum conditions, the results of the analysis of synthetic sample solutions by aqueous standa rds calibration graphs well agree with those obtained by the method of stan dard additions. Recoveries ranged from 99 to 101% and the relative standard deviation is around 1%. Detection limits for Ni, Co and Fe in Li/K carbona te salts are similar to that in aqueous solutions, i.e. 0.5 x 10(-6) g anal yte/g (Li-0.62, K-0.38)(2)CO3. Furthermore, a background absorption is easi ly compensated by D-2 background correction, which does not affect the sens itivity. The proposed method is applied to the determination of cobalt in r eal melt samples. (C) 1999 Elsevier Science B.V. All rights reserved.