Gas analysis

The following methods can be used, clinically or experimentally, to detect carbon

dioxide, EXCEPT for which one?

a) Infrared light spectroscopy

b) Infrared photoacoustic spectroscopy

c) Raman spectroscopy

d) Polarography

e) Chromatography

Answer: d

Explanation

Three techniques may detect all gases pertinent to anaesthesia (oxygen, carbon dioxide,

nitrous oxide, nitrogen and volatile anaesthetic agents). They are mass spectrometry,

Raman spectroscopy and gas chromatography. Oxygen may also be detected by polarography

(Clarke electrode), fuel cell and paramagnetism. Molecules with two dissimilar

atoms (carbon dioxide, nitrous oxide and volatile anaesthetic agents) may be

detected by infrared light spectroscopy and infrared photoacoustic methods. Finally,

volatile anaesthetic agents may also be measured by piezoelectric resonance.