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7.3.2 Extracted Ion Chromatogram

Suppose you were only interested in compounds that have an m/z 77 signal in the mass spectrum. This is part of the power of collecting the three dimensional GC/MS data. Instead of plotting the total ion current vs. time, one can choose to plot a single mass (or small range of masses) signal vs. time. This Extracted Ion Chromatogram (EIC) allows the mass spectrometer to be used as a selective detector. One can display data only for peaks of interest in cluttered TIC's.

Exercise: Display the m/z 77 EIC for the file EVALDEMO.D. How many of the detected compounds in the TIC show this fragment?

Exercise: Simultaneously display the m/z 154 and 188 EIC's for EVALDEMO.D. Compare these chromatograms to the TIC and the m/z 77 EIC.

John S. Riley, DSB Scientific Consulting