INFICON HAPSITE ER Chemical Identification System - Manual (Page 445)

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HAPSITE ER Operating Manual
14.9 Background Cleanup
14.9.1 Introduction
The SituProbe / HAPSITE system, with Concentrator installed, routinely detects
VOCs at the ppt level. Occasionally, an operator may unknowingly expose the
system to an excessively high VOC level resulting in carryover in subsequent blank
analyses. The chromatogram indications of carryover can be broad baseline
increases or individual peaks of the analytes or other matrix VOCs that persistently
appear. Polymer components such as PEEK™ tubing in Transfer Lines and
Teflon® in Diaphragm Valves are likely sources of carryover. If the background
persists after a few blank runs with clean water then more aggressive measures
may be required.
14.9.2 Cleanup Steps
Probe Head . . . . . . . . . . . . . . . . . . . Because the contamination must originate
with the water sample, the probe head
should be cleaned. Thoroughly rinse the
probe head with VOC-free water. Unscrew
the glass or plastic purging sleeve being
careful not to damage the other components
in the probe head. The sealing o-ring can
also be removed and rinsed with water.
Clean the sleeve in detergent followed by
thorough rinsing with VOC-free water. Gently
wipe the probe head components and
surfaces that show signs of contamination.
Re-install the purging tube.
NOTE: The purge tube and o-ring are
replaceable items.