Quantification of lithium in molten chlorides by optical emission spectrometry using a novel molten-salt-electrode microplasma source.

A new molten-salt-electrode microplasma (MSEMP) source for optical emission spectrometry (OES) was constructed, equipped with a molten salt electrode and a metal hollow tube (fed with helium) counter electrode. The use of the MSEMP-OES for constituent analysis of molten salt was primarily evaluated. The acquirement of characteristic spectral lines of some elements in several molten chloride samples verified the good qualitative ability of the proposed MSEMP-OES. Solid copper was dissolved via charge transfer and excited in glow discharge, indicating its potential application in solid sample analysis. The temperature and composition of molten salt were found to have no influence on the lithium response and the accurate quantification of lithium in molten salt was achieved. This work provides new insights for promoting the application of microplasma technology in the in-situ analysis of elements, even in special samples.