Self-calibrating interference refractometer using a linear photodiode array for anaesthetic gas analysis
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The laboratory standard for measurement of gas concentrations in binary mixtures is the manually operated interfence refractometer. We describe an automatic interference refractometer for theatre use incorporating a linear photodiode array and using digital electronics for signal analysis. The support system performs automatic self-calibration, samples gases from an anaesthetic machine, feeds them to the refractometer and presents information on gas concentrations and possible alarm conditions to the anaesthetist. The instrument may be incorporated into a new anaesthetic machine or may be an addition to an existing one. The instrument may also be applied in other fields where concentrations of known gases need to be monitored automatically.
KeywordsAnaesthetics Gas concentration Online gas analysis Refractometer
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