Fig. 6. Data from an experiment with 5% sevoflurane in 2 l/min oxygen using gas chromatography to confirm our results. Carbon monoxide (CO) concentrations were determined every 5 min by the three methods. All three methods are in good accordance. Gas chromatography results, average of duplicate measurements (solid line), were slightly higher than the IR results (dotted line), but slightly lower than electrochemical results (dashed line). IR = infrared.