Revised δ 30 Si consensus values for BHVO-2, big batch, diatomite and IRMM-018 secondary reference materials using literature compilation

Secondary isotope standards play a vital role in the assessment of measurement accuracy across studies and the evaluation of long-term reproducibility. Here we compile almost two decades of measurements of the Si isotope secondary standards BHVO-2 (17 years), Big Batch, Diatomite and IRMM-018 (all 18 years) reported in the literature and provide updated consensus Si isotope values for these materials. The revised mean consensus δ 30 Si values and uncertainties (95% CI) are −0.29 ± 0.004‰, −10.56 ± 0.03‰, +1.25 ± 0.005‰ and −1.65 ± 0.04‰ for BHVO-2, Big Batch, Diatomite and IRRM-018, respectively. Comparisons of the updated and original mean isotope values for these secondary standards show no or small differences: 0.00‰ for BHVO-2 and IRMM018, −0.05‰ for Big Batch, and −0.01‰ for Diatomite, but with substantially reduced uncertainty (95% CI) for each material.