Metal species in solid and liquid materials can be extracted into supercritical CO2 containing organic complexing agents. The solubility of metal complexes in CO2 is an important factor in determining the extraction efficiency. A spectroscopic method utilizing a high-pressure fiber optic system for determination of solubility of metal complexes in supercritical CO2 is described. Fluorination of the ligand, replacement of the coordinated H2O with a lipophilic Lewis base, and formation of ion pairs with a fluorinated counteranion are some of the techniques that can be used to enhance the solubility of metal complexes in supercritical CO2. Direct dissolution of uranium oxides and selective extraction of aqueous strontium are two examples given in this paper to illustrate the capability of this in situ chelation/supercritical fluid extraction technology. Potential applications of the extraction technology for treatment of metal-contaminated wastes including mixed wastes and nuclear wastes are discussed.