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Figure 8.—Origin and appearance of the mass spectra of two amino acids.
Figure 8 shows the mass spectra of two amino acids, phenylalanine and tyrosine. Upon electron bombardment, certain bonds in the molecules of phenylalanine (top) and tyrosine (bottom) are broken to form various positively-charged fragments which the mass spectrometer separates and records according to mass (see curves). Both give mass 74, characteristic of many amino acids, but the rest of the peaks differ because tyrosine contains one more oxygen atom than phenylalanine.
Any mass spectrometer built for use in space would, of course, incorporate a collection apparatus for sampling, sensors to note the results, and telemetry equipment to communicate these results back to Earth. Such information would be obtained quickly with this instrument. The entire mass spectrum of a biological molecule can be scanned in a few seconds. The instrument should be designed for the determination of spectra up to a molecular weight of 250.
