Equilibrium Measurements of the NH₃-CO₂-H₂O System: Speciation Based on Raman Spectroscopy and Multivariate Modeling

Figure 4

PLS-R model for carbonate. (a) Score plot of PLS components 1 versus 2 showing the calibration samples and validation samples. (b) Regression coefficients based on a one-component PLS-R model. (c) The residual validation variance shows that one PLS-component is optimal. (d) Predicted carbonate concentrations based on the one-component PLS-R model versus the reference concentrations obtained from the solute ion preparation stage.

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