Preparation of in-house reference material of Fe, Ca, Ni and Si in carbon sample from an aluminum industry and results of a proficiency test

Abstract

This work presents the preparation of a reference material for Fe, Ca, Ni and Si in order to ensure the quality of the analysis of these elements in routine samples of carbonaceous materials in a aluminum industry. The sample was fractioned and bottled for homogeneity and stability studies before being shipped to interlaboratory certification. Then, we sent a bottle for each one of seven participating laboratories to define the reference values. The results of concentration for Fe, Ca, Ni and Si, after outlier exclusion were 589.1 ± 25.3, 142.9 ± 12.0, 178.1 ± 9.3 and 134.2 ± 6.6, respectively. Finally, we applied the technique of z-score, to evaluate the performance of the participating laboratories. After the results of this study we can conclude that the carbon material can be used like reference material for in-house control of Fe, Ca, Ni and Si analyses.