Determination of metal impurities in ultrapure CaCl2 and MgCl2 by ICP OES

An effective, rapid and simple analytical method for the determination of Na, K, Ca, Mg, Cd, Pb, Ba, Fe, Mn, Sr, Zr, Cu, Zn and Al at mg kg−1 levels in the ultrapure salts MgCl2 and CaCl2 using optical emission spectrometry was developed. Optimisation of the operation conditions was performed with real samples of ultrapure MgCl2 and CaCl2. The results of the determination with multi-elemental water standards were compared to the internal standardisation, the standard addition method, and the maximum allowable content of the above mentioned elements in pure chemicals. The method was shown to be very sensitive with the following limits of detection: Na 1.01, K 3.12, Ca 0.263, Mg 0.275, Cd 0.0832, Pb 0.482, Ba 0.0153, Fe 0.0528, Mn 0.0473, Sr 0.0203, Zr 0.638, Cu 0.0732, Zn 0.0686 and Al 0.459 (all in mg kg−1). The method exhibited satisfactory precision, high analytical recoveries, linear responses of an accuracy of at least 4 orders of magnitude and low contamination susceptibility.