A Micromethod for the Determination of Carbon Dioxide in Blood and Other Fluids

Christensen and Facer (1) have devised an apparatus and procedure for the microdetermination of carbon and hydrogen in organic compounds by a wet combustion process in which the evolved carbon dioxide is absorbed in standard barium hydroxide. The apparatus used for the determination is based on the principle of Pettenkopfer (cf. (2)) in which the carbon dioxide is drawn into an evacuated vessel containing the standard base. By slightly modifying the above apparatus of Christensen and Facer, it has been found possible to use it for the precise determination of the total carbon dioxide of plasma and other solutions. The methods commonly used for such determinations are the manometric (3, 4), volumetric (57), and titrimetric (8) procedures of Van Slyke and associates. The manometric and volumetric methods, while precise, require rather expensive equipment, considerable experience in manipulation, and the use of certain factors peculiar to the solutions being analyzed. The titrimetric method involves the titration of a buffered solution, and, while being sufficiently accurate for clinical purposes, is not of research precision. The procedure here presented has the advantages of requiring relatively simple apparatus and little manipulative skill, and yielding results comparable to those obtained by the manometric method.