Gas-Chromatographic Method For Determination Of Total Co2 Content In Biological-Fluids, By Means Of Head Space Sampling Technique, Based On Methane Conversion Principle

A simple and sensitive gas-chromatographic method is presented for the determination of the total carbon dioxide content in biological fluids, which needs a sample volume of 50 μl. Carbon dioxide, present as bicarbonate in the aqueous phase, is transferred into gaseous carbon dioxide by 0.1 N lactic acid, after which one ml of the head space vapour is analysed by means of gas chromatography. After passing the Chromatographic column, carbon dioxide is reduced catalytically into methane, and quantified by means of a flame ionisation detector. The technique proposed combines a high sensitivity (detection limit ⩽ 2.5 nmole bicarbonate) with excellent reproducibility (S.D. = ± 0.3 mmole/1). Also this method can be used for the determination of carbon dioxide in air, or other gas mixtures, while calibration can be performed by means of bicarbonate or carbonate standard solutions.