Page:Concepts for detection of extraterrestrial life.djvu/28

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18
DETECTION OF EXTRATERRESTRIAL LIFE

Figure 5.—Gas chromatograph.


Figure 6.—Block diagram of the gas chromatograph.


Biological substances do not normally occur as vapors and therefore cannot be directly detected by gas chromatography. In the analysis of these compounds it is necessary to convert nongaseous materials to vapor form before