INFICON Explorer Portable Gas Chromatograph - Manual (Page 234)

Calibration
232
TVOC Calibration
The TVOC mode must be calibrated in order to display concentration in ppm units
equivalent to the calibration gas. Calibration gas, containing a known concentration
of a photoionizable gas or vapor, is used to set the sensitivity.
A standard of isobutylene at a known concentration is recommended for setting
the TVOC sensitivity. If
Explorer is calibrated with isobutylene, it displays
concentrations in units equivalent to ppm of isobutylene. If isobutylene were the
only photoionizable compound in the sample, then
Explorer would display its
concentration directly.
Explorer responds more or less readily to other compounds than it does to
isobutylene. Because it has a medium sensitivity to isobutylene, this gas has
been chosen as a reliable means of reporting an average concentration of total
photoionizable volatile organic compounds.
For special applications, gases other than isobutylene can be used to calibrate
Explorer. Contact INFICON for more information.
If you are using the long probe or the extended probe for sampling, then
ensure the probe is connected to
Explorer and press Enter Menu, then
SETUP, MODE, INJECT and PROBE and select the probe you are using.
Explorer will then adjust its pump time so that the pump will draw an
accurate sample.
NOTE: Ensure the sample probe is free of any contamination as this will affect the
calibration.
1. Press Enter Menu, then DISPLAY, VOC and REPORT to ensure Explorer is
in TVOC mode.
2. Press Enter Menu, then LIBRARY and ALARM and enter an alarm level.
3. Press SPAN and enter the span gas concentration.
4. Press Enter Menu to clear the menu.