Applications of gas chromatography to anaesthesiology 1. Gases and vapours

Conclusion

Analysis of anaesthetic gases and vapours by gas chromatography is accurate, simple, and fast. Most of the agents possess thermal conductivities of sufficient magnitude so that a small change in the composition of a mixture produces sufficient change in the chromatogram to allow accurate analysis. There can be no doubt that physical methods of analysis are more accurate and less tedious than the time-honoured chemical procedures. The majority of the physical analytical techniques require expensive, complicated, fickle instrumentation, which in turn must be operated by trained, skilled technicians. Gas chromatography, utilizing a thermal conductivity detector, while hardly inexpensive, is a relatively simple technique which can be mastered by the average technician in a matter of hours. As is the case in all analytical techniques, the accuracy and reproducibility of the determination is dependent upon the accuracy with which standard gas mixtures can be prepared. This is the limiting factor in the effective use of this technique. It should be emphasized that in spite of statements to the contrary, this is essentially a research tool and at present has no place in the monitoring of the routine clinical anaesthetic.

The application of this technique, in anesthesiology, is currently limited to analysis of volatile and gaseous agents, and fixed respiratory gases. The horizons, however, are unlimited. Barbiturates, phenothiazines, narcotics, amino acids, and amines of biological interest can all be quantitated by slight modifications of the chromatographic technique described.