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

Figure 5

PLS-R model for bicarbonate. (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 bicarbonate concentrations based on the one-component PLS-R model versus the reference concentrations obtained from the solution preparation stage.

(a)

(b)

(c)

(d)