Inficon HAPSITE ER, Operating Manual, Page: 24 / 436

7 | Introduction INFICON
24 / 436 074-471-P1E HAPSITE ER Operating Manual
HAPSITE ER uses internal standards to verify the performance of the Gas
Chromatograph and Mass Spectrometer. The internal standard is composed of two
volatile organic gases which are injected into the sample inlet flow. The internal
standards’ retention times and responses are used to ensure proper instrument
performance.
A graph of eluting gases from the Gas Chromatograph is shown below This graph is
called a Total Ion Chromatogram (TIC) and is plotted as a function of time (x-axis)
verses response (y-axis).
7.6.1 Membrane Isolation Valve
Gas eluting from the GC column passes through the membrane isolation valve. When
the membrane isolation valve is opened, organic compounds are permitted to enter
the Mass Spectrometer.
In the Survey mode of operation, in which air samples bypass the GC directly to the
Mass Spectrometer, the sample pump draws the air sample directly across the
membrane with the isolation valve in the open position.
7.7 Mass Spectrometer
The mass spectrometer is comprised of three basic physical systems: ionizer, mass
selector, and ion detector. These are mounted together in a vacuum manifold which
also includes: an inlet, two vacuum pumps, and a portion of the vacuum interconnect
valve, as shown in the figure in Instrument Overview [ } 22]. The figure below is a
representation of the three sub-systems of the mass spectrometer.