A Rapid Method of Carbon Analysis for Biological Materials

An induction furnace and a gasometric analyzer have been adapted for the analysis of carbon in biological materials. Samples for analysis must not exceed 70 mg carbon. The number of analyses which can be routinely performed for carbon in an eight-hour day has been increased from 8, by wet combustion, to 50, by the induction furnace method. Hay, concentrate, dried feces, wet feces, milk, and urine have been analyzed by this method with iron, cupric oxide, molybdenum trioxide, and silicic acid used as reagents. Silver phosphate and vanadium pentoxide were required to obtain satisfactory analyses of dried milk. Liquid urine was analyzed successfully by the same methods employed for dried samples except for minor modifications of the combustion tube and catalysts. Analyses on sodium carbonate, glucose, and potassium hydrogen phthalate yielded carbon recoveries of essentially 100%.