INFICON HAPSITE ER Chemical Identification System - Manual (Page 225)

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HAPSITE ER Operating Manual
Figure 6-6 Additional Calibration Points
Additional compounds are added by following the same steps.
CAUTION
The Reset Library function is used to delete all
calibration curves for all compounds and should only be
checked when this action is necessary.
6.2 Analyze (GC/MS) Methods
GC/MS is a reliable means of identifying volatile organic compounds. The sample
is drawn in through the probe or other sampling accessory. It is then passed
through the GC, where the sample is separated by boiling point and sent to the
Mass Spectrometer. Compounds are positively identified by GC retention time and
Mass Spectrum.
Analyze (GC/MS) Methods provide identification of compounds in two ways. By
extracting target mass ions from the MS response or as a result of searching the
total MS response against the AMDIS and/or NIST libraries. GC/MS Methods can
use Selected Ion Monitoring (SIM) or Full Scan MS modes. The sensitivity of an
Analyze (GC/MS) Concentrator method (Full Scan) will be in the range from high
ppt to low ppb. By comparison, a SIM method will always give slightly improved
sensitivity over a Full Scan method as these methods focus on a limited set of
masses for detection. The sensitivity is related to the compound and sampling
system; the above are general guidelines.