Method for elemental analysis of iron meteorite by total-reflection X-ray fluorescence (TXRF) spectrometry: novel application to Sikhote-Alin meteorite

Classification of iron meteorites is based on their structure and elemental composition. The chemical composition classification is based, especially on Ni, Ga, Ge, Co, Au and Ir mass fractions and divides iron meteorites into 13 groups. In this work, the potential of elemental analysis of iron meteorites using the TXRF method is explored. In the absence of certified reference materials for iron meteorites, the Sikhote-Alin meteorite was chosen for methodological research due to its high degree of homogeneity in elemental composition. The TXRF method was developed for the determination of Fe, Ni, Ga, and Ge following 6 M nitric acid decomposition and a standardless quantification approach. Liquid-liquid extraction with MIBK was employed to remove Fe from the matrix, and Co and Cu were also determined. The precision did not exceed 4 % for Fe, Ni, Cu, and Ge, 8 % for Co, and 11 % for Ga. The trueness, based on recovery values, was generally in the range of 90–110 % for all elements. The TXRF method enabled detection at the first microgram per gram (μg/g) levels and was considered satisfactory for most types of iron meteorites.