Interlaboratory Application of Raman CO₂ Densimeter Equations: Experimental Procedure and Statistical Analysis Using Bootstrapped Confidence Intervals

Raman spectroscopy has been used extensively to calculate CO 2 fluid density in many geological environments, based on the measurement of Fermi diad split (Δ; cm –1 ) spectrum. While recent research allowed calibration several densimeters, there is a limit interlaboratory application published equations. These two classes values for same measured Δ, with deviation 0.09 ± 0.02 g/cm 3 average. To elucidate influence experimental parameters we propose bottom-up approach beginning new equation, evaluate possible instrument-dependent variability induced by conditions. Then, develop bootstrapped confidence intervals estimate existing equations move statistical analysis from sample-specific population level. We find that densimeter calibrated spectra acquired similar spectral resolution lying within standard errors and are suitable application. The confirms at densities equivalent 95% confidence, each does have applicability, statistically defined minimum Δ value, below which error calculated too high.