Note: This report will describe a method to quantify the CO2 capture efficiency of solid sorbents with CaO as a benchmark sorbent under post combustion capture conditions. Traceable primary reference gas mixtures were used in these experiments to ensure that the quantification was accurate. The effect of impurities and amount of CO2 in the flue gas was assessed by varying the composition of the PRMs used for the tests. An uncertainty budget was developed to include all uncertainties involved in the measured using GUM. The initial objective of the activity to test solvents was not tested as the rig available to do the testing could not handle any solvents. Therefore, a change request was placed and approved to test solid sorbents for quantifying carbonation efficiency. The deliverable was successfully achieved for testing carbonation efficiency of solid sorbents.