ONLINE COUPLED ION CHROMATOGRAPHY-ICP-(AES, MS) AND ELECTROTHERMAL VAPORIZATION-ICP-MS IN USE FOR ULTRA-TRACE ANALYSIS OF HIGH-PURITY RHENIUM

This work presents the benefits of coupling techniques such as Electro Thermal Vaporisation (ETV)-ICP-MS and Ion Chromatography (IC)-ICP-(AE S, MS) for ultra trace analysis in a high purity rhenium powder sample . Direct analysis using ICP-AES suffers from poor detection limits and allows trace analysis only above 1 mug/g for most analytes. ICP-MS an alysis of trace elements is more sensitive, but signal depression caus ed by the heavy Re-ions limits trace analysis to concentrations of 50 - 100 ng/g analyte in the solid sample. Coupling Ion Chromatography wi th ICP-spectrometers, combined with time resolved measurement (IC-ICP- TRM) of the elution signals, was used to enhance the sensitivity of bo th ICP-AES and ICP-MS. Resulting detection limits are in the very low ng/g to pg/g range. Coupling of ETV and ICP-MS offers the possibility of eliminating the volatile Re2O7 matrix by thermal pretreatment and a llows ICP-MS measurements without matrix interferences caused by Re. R esults from these methods are compared with Glow Discharge Mass Spectr ometry (GDMS) analysis, a semiquantitative solid state technique. The results are also compared with the manufacturers' specifications to sh ow the power of modern routine analysis using ICP-AES or FAAS.