Modification of Van Slyke's Gas Apparatus for Determination of CO 2 in Muscle and Other Tissues

Abstract

For the determination of CO₂ in muscle and other tissues it is obviously necessary to modify the gas burette of Van Slyke and Neill 1 so that relatively large pieces of material can be introduced into the burette. Ferguson and Irving 2 have proposed to divide the burette into 2 separate parts just below the 2 cc. mark, the 2 parts being connected by means of a ground joint and held together with a pair of springs. In our laboratory several modifications have also been used. The one that seems most satisfactory is shown in Fig. 1.

The new feature of the burette is the enlargement of the diameter of the lower stem of the burette and the introduction of a 15 cc. bulb between the burette and the flexible point. The short stem of the bulb is ground on the outside to fit the lower stem of the burette which is ground on the inside. The joint is surrounded by a cup for mercury seal and the cup is provided with an annular rubber cover to prevent the escape of mercury during shaking.

For the determination of CO₂ about 0.5 gm. of muscle is taken from the animal and immediately put into a weighed, stoppered test tube containing a solution which stops respiration, hinders lactic acid formation and prevents loss of CO₂. The solution is made by mixing 1 cc. of 0.3 N CO₂-free NaOH and 3 cc. of 0.8% saline containing 65 mg. KCN and 1 gm. NaF per liter, and 2 drops of 0.1% phenol red solution. The tube is weighed again to obtain the weight of the muscle.

The material to be analyzed is introduced into the bulb, the burette is placed on it, stop-cock vaseline being used at the ground glass joint.