Certification of a Natural Silicon Reference Material with SI‐Traceable Isotopic Composition

Abstract

Silicon (Si) is the second most abundant element in the continental crust. Studies have illustrated that silicon isotopes have a potential to be tracers in the biogeochemical silica cycle. This paper details a developed method for the production and certification of a new Si reference material with natural‐like isotopic composition using a fully calibrated multi‐collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS). To correct for the mass bias effect, three blend solutions were gravimetrically prepared with isotopically enriched 28Si, 29Si and 30Si materials. Homogeneity and stability tests were performed, and no significant influences were found. Uncertainties of property values were evaluated, and the traceability to the International System of Units (SI) was established. The developed certified reference material (GBW04503) is a silicon powder (≈ 300 mesh) with high purity (≈ 0.999 99 kg kg−1), which can be used in silicon isotopic measurement to support validation of analytical procedures and/or quality control of gas source mass spectrometry (GS‐MS) or MC‐ICP‐MS. The certified isotope amount ratios of n(29Si)/n(28Si) and n(30Si)/n(28Si) are 0.050291(12) mol mol−1 and 0.033397(16) mol mol−1, respectively, (k = 2), and the certified isotope amount fractions of silicon are 92.2776(20)% (28Si), 4.6407(10) % (29Si) and 3.0818(14)% (30Si) (k = 2). Meanwhile, the delta value of δ30/28SiNBS 28 = 1.679(17)‰ was obtained (k = 2).