The loading amount of IL-2 was optimized by comparing the average yields of 2c obtained in five independent experiments under each loading condition (runs 5-8). When 350 mg of IL-2 was used, an average yield of 65(3)% was confirmed (run 5), while using 100 mg of IL-2 (run 6) furnished a yield of 54(3)%; however, this difference was not confirmed to be statistically significant. Nevertheless, the desorption efficiency significantly decreased when 500 mg (39(3)%; run 7) or 1000 mg (45(3)%; run 8) of IL-2 was employed, even though more 3c could be dissolved in IL-2 under these conditions. Based on the aforementioned results, the CO desorption should occur predominantly on the dispersed solids of 3c, and the amount of IL should influence the efficiency of its dispersion. The amount of IL should be optimized based on the reaction apparatus; accordingly, we employed 350 mg of IL-2 in the reaction vial (V = 2.0 mL) in subsequent experiments.