Аннотация:Platinum reacts with CO at T=950oC and P=200 MPa with formation of carbonyls. Studying of the quenching phases has got information on the possible speciation of Pt in CO-CO2 fluid. At quenching carbonyl can be partially conserved. Concentration of quenching platinum phase soluble in the acetone is only 0.01-1 ppm corresponding to the concentration in the fluid of 2-11 ppm. In the solutions kept in the contact with air for a day nanoparticles of Pt were formed that enables observation of Raman bands of carbonyl Pt3(CO)6]n2-. Thus conditions of our spectral measurements resemble SERS method.