High purity aluminum analysis

Significance of the topic

High purity aluminum with 99.999 percent or higher purity is critical in electronics, optics and flexible packaging. Trace levels of impurities, especially alpha emitters such as uranium and thorium, can degrade device performance or lead to failures. Ultra trace analysis at sub parts per billion levels is therefore essential for quality control and material certification.

Objectives and study overview

This study demonstrates routine ultra trace analysis of high purity aluminum grades using a glow discharge mass spectrometer. The aim is to achieve reliable quantification of more than 70 elements directly in the solid sample with minimal preparation, low detection limits and adequate sample throughput for industrial applications.

Methodology and instrumentation used

High purity aluminum samples were freshly milled to expose a clean surface and avoid contamination. A 10 minute pre sputter step removed residual oxide and surface impurities. Analysis was carried out in continuous direct current mode with an argon flow of 450 ml per minute at 75 milliamp discharge current and approximately 750 volt. Sample material was ablated from an eight millimeter diameter area. The sector field mass analyzer operated at medium resolution to resolve polyatomic interferences. Calibration employed ion beam ratios measured on certified reference materials and standard relative sensitivity factors for elements not certified in the CRMs.

Main results and discussion

Reproducible data were obtained with detection limits below one part per billion and quantification uncertainties better than plus minus 30 percent. Certified reference material Alcan 112 03 was measured for 70 elements with most values matching the certified ranges. Actinides thorium and uranium were determined at 0.017 ppb and 0.029 ppb respectively, demonstrating ppt level capability. An alternative CRM, Hydro R 02, yielded sub tenth of a ppb levels for lanthanides and bismuth, confirming the instrument sensitivity.

Benefits and practical applications

Glow discharge mass spectrometry enables direct solid analysis without chemical digestion and reduces contamination risk. The high sputter rate and sensitivity allow rapid screening of ultra trace impurities. Sample throughput of three samples per hour supports high volume quality control in semiconductor, electronic and packaging industries. The method ensures compliance with stringent purity specifications.

Future trends and opportunities

Further enhancements in sensitivity and resolution could extend detection to single digit parts per trillion. Automation of sample loading and data processing may improve throughput. Expanding the approach to other high purity metals and combining with isotopic ratio analysis or hyphenated techniques could broaden application scope. Integration with laboratory information systems will streamline quality assurance workflows.

Conclusion

The Element GD Plus glow discharge mass spectrometer provides a robust and highly sensitive platform for ultra trace impurity analysis in high purity aluminum. Minimal sample preparation, sub ppb detection limits and fast throughput make it a valuable tool for quality control and certification in advanced material applications.

References

• Thermo Fisher Scientific Application Note 30142 High purity aluminum analysis 2019