INFICON HAPSITE Smart Plus Chemical Identification System - Manual (Page 390)

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HAPSITE Smart Plus Operating Manual
Start Mass . . . . . . . . . . . . . . . . . . . . The mass at which the Mass Spectrometer
will start to scan. The starting mass can be
set from 1-300 AMU.
NOTE: Start as high as possible to decrease
the scan time and collect as many
scans as possible.
NOTE: If possible, avoid starting below 45
AMU. There is a significant response
to components of air at mass 44 and
below. This would add to the
instrument background and make it
more difficult to detect low
concentrations of other compounds
in the TIC.
End Mass . . . . . . . . . . . . . . . . . . . . The mass at which the Mass Spectrometer
will end a scan. The end mass can be set
from 1-300 AMU.
NOTE: End the scan at least 2 AMU above
any mass used for compound
identification. End as low as possible
to decrease the scan time to collect
as many scans as possible.
Dwell Time. . . . . . . . . . . . . . . . . . . . The Dwell Time is the length of time the Mass
Spectrometer will sample data at each
sampling point. The longer the Dwell Time,
the better the signal to noise ratio of the
Analyte.
Run Time . . . . . . . . . . . . . . . . . . . . . The time span of the method from start to
finish.
11.8 SIM Page
WARNING
Only trained users should modify methods. Changing
parameters may result in incorrect analysis.
Figure 11-25 shows the SIM page, which is presented with different content
depending on the mode of analysis — Analyze (GC/MS) or Survey ( Figure 11-26 ).
Selected Ion Monitoring (SIM) uses a set or sets of specific masses to scan with
the highest sensitivity for known compounds.