ASTM F1710-08, titled “Standard Test Method for Determination of Trace Metallic Impurities in Electronic Grade Titanium by High Resolution Glow Discharge Mass Spectrometer“, was withdrawn in 2023 with no replacement. The original method was developed for commercial GDMS model VG9000. Since then, newer commercial GDMS instruments have been introduced to the market, specifically, the model Astrum ES from Ametek Nu Instruments. While the Astrum ES was specifically designed to replace the VG9000, there are key differences between their designs, such as the cryo-cooling of the GD cell, ion optics, reverse versus forward geometry, Daly vs MIC detector, among others. These differences warrant a thorough investigation of the analysis conditions for determination of trace impurities in electronic grade Ti samples by the Astrum ES.

The Astrum ES is a forward geometry magnetic sector instrument. It utilizes an ion counter, as opposed to a Daly detector, which provides lower background noise. The newer optics in the Astrum ES also translate to better abundant sensitivity relative to the VG9000 while maintaining comparable ion transmission yields and sensitivity. One of the most important differences between the VG9000 and the Astrum ES is the glow chamber. Specifically, the VG9000 cooling plate is located immediately around the sample orifice on the cell front plate, while the Astrum ES utilizes a large cooling block on the bottom of the cell. This difference in design can result in different plasma conditions inside the cell during analysis.

We analysed high purity Ti reference samples using a variety of analytical conditions to investigate the impacts on ion beam ratios in the Astrum ES. Understanding the conditions in which Ti measurements are reproducible and repeatable equally to the ASTM F1710 test method will enable to replace and/or amend the withdrawn ASTM F1710-08 standard test method to be suitable to the currently available commercial GDMS instruments.