Inductively Coupled Plasma Atomic Emission Spectroscopy for the Analysis of Trace Elements in Boron Materials

Abstract

An investigation into the application of inductively coupled plasma atomic emission spectroscopy (ICP/AES) to the quantitative determination of trace level multi-element impurities in boron materials has been undertaken. Two ICP-Spectroscopic systems were developed and applied. An ICP-Spectrograph system, which uses photographic detection and computer controlled microdensitometry for plate evaluation, provided wide element coverage and is well suited to dealing with complex emission spectra. The ICP-Scanning monochromator system, which is equipped with photoelectric detection, gave the better sensitivity and precision. Combined, the two systems provided useful detection limits (typically <1 ppm), good accuracy and precision for 50 elements. In order to apply ICP/AES to cases where the sample quantity was limited a recirculating nebuliser was developed and tested. A xl0 improvement in efficiency over conventional methods of nebulisation was achieved without any deterioration in sensitivity or precision. A microprocessor controlled version provided a suitable approach to routine analysis and a detailed study into the nebulisation characteristics showed that the nebuliser was free from the instabilities apparent in other designs of closed system nebulisers. Sample introduction by hydride generation was investigated and provided ng/ml detection limits for several elements which were not sufficiently sensitive by pneumatic nebulisation. A comparison of ICP/AES, neutron activation analysis and spark source mass spectrometry showed that only by using all three techniques could the full requirements be met. ICP-Mass spectrometry and X-ray fluorescence have been examined and preliminary assessments indicated that both techniques have considerable potential for boron analyses.