Quality assessment of INAA data for small-sized environmental reference samples

Area of Science:

• Analytical Chemistry
• Nuclear Chemistry
• Materials Science

Background:

• Accurate elemental analysis is crucial for materials characterization.
• Certified Reference Materials (CRMs) are essential for quality assurance and control (QA/QC).
• Analyzing small sample sizes presents unique challenges in elemental determination.

Purpose of the Study:

• To assess the accuracy and precision of instrumental neutron activation analysis (INAA) for trace elements in small sample aliquots (1-2 mg).
• To evaluate the suitability of NIES No. 8 and NIST 1632c CRMs for mg-scale INAA.
• To compare the analytical capabilities of different laboratories using established QA/QC metrics.

Main Methods:

• Instrumental Neutron Activation Analysis (INAA), including comparative and k0-INAA methods.
• Analysis of two CRMs (NIES No. 8 and NIST 1632c) using 1-2 mg aliquots.
• Repeated analysis (>10 times per CRM) across four participating laboratories.
• Quality assurance and control (QA/QC) assessment using z-scores and zeta scores.

Main Results:

• Successful determination of 16-18 minor and trace elements in mg-scale CRM aliquots.
• Significant variations in analytical performance were observed among participating laboratories.
• Z-scores and zeta scores indicated differences in laboratory analytical capabilities.

Conclusions:

• The studied CRMs (NIES No. 8 and NIST 1632c) are validated for use as reference materials in mg-scale INAA.
• The findings highlight the importance of robust QA/QC protocols when analyzing small sample sizes.
• INAA is a viable technique for precise trace element determination in microgram quantities.