Rapid and sensitive method for the analysis of carbon monoxide in blood using gas chromatography with flame ionisation detection

In order to measure changes in physiological CO concentrations in blood with good accuracy, a method was developed using gas chromatography with flame ionisation detection (250°C). A nickel catalyst system was fitted to convert CO to methane at 375°C after separation with a molecular sieve column at 35°C. Helium was used as carrier at 30 ml/min. Porcine or human blood (400 μl) was sampled in gastight tubes and treated with sulfuric acid and saponin (800 μl). Accuracy was 1.4% and 1.5% (RSD), respectively. Precision was 2.8% (porcine blood). Limit of detection was 0.01 nmol/ml gas and limit of quantification 12 nmol/ml blood. Calibration was made in the interval 12–514 nmol/ml blood (corresponding to 0.1–6% COHb). Samples were stable for at least a month at +4°C. This paper describes a method with high sensitivity and good accuracy, suitable for analysis of low CO concentrations.