INFICON HAPSITE Smart Plus Chemical Identification System - Manual (Page 452)

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HAPSITE Smart Plus Operating Manual
13.3.1 Clean Out after a High Concentration Sample
When high concentration samples are analyzed using the HSS, the system can
retain analytes which will be detected if the next sample has low levels of those
compounds. This is typically referred to as a carry-over contamination. Carry-over
contamination can be reduced to approximately 0.1% by using Purge. In the case
of severe carryover, use the Flush function.
13.3.1.1 Purge Procedure
To purge the HSS, run a blank with the HSS needle in a clean, empty 40 mL purge
vial. In some cases, the blank may need to be run more than once.
HINT: A blank is the same method run without introducing a sample.
13.3.2 Cleaning Up a High Background
High background is usually encountered because some compounds are retained
in the HSS or the HAPSITE. These compounds could be in the HSS valves,
transfer line, or within the HAPSITE.
To test whether the background is in the HSS or the HAPSITE, disconnect the
Transfer Line, connect the air sampling probe to the HAPSITE, and analyze a clean
air sample. If the contamination is no longer present, the contamination is in the
HSS or Transfer Line.
Once the HAPSITE has been tested, test the Transfer Line by reconnecting it to the
HAPSITE and disconnecting it from the HSS. Perform an analysis of clean air with
the Transfer Line connected. If the contamination is not present, then the
contamination is in the HSS.
13.3.2.1 Flush Procedure
Contamination may be flushed from the HSS by disconnecting the Transfer Line
from the HAPSITE but leaving the line connected to the HSS. Once the Transfer
Line to the HAPSITE is disconnected, press the FLUSH switch inside the front
panel of the HSS (see
Figure 13-9 ). This will pass Nitrogen through the system
while heating the sample well to 80 °C. The length of time the flush will need to
operate will depend on the level of contamination.
NOTE: The Flush function will continue to operate until the FLUSH toggle switch
is pressed again to turn it off.
HINT: Make sure that the HSS needle is inserted into a clean, new, empty vial
during flushing.