INFICON 2020ppbPRO Portable Photoionization Detector - Manual (Page 62)

56 ISP-074-576-P1D 56
Figure 15. Sample Collection Mode
Response Factor Library
The response of a PID to a compound is dependent on its ionization potential. In
certain situations when the user is confident that only a single specific compound
exists, they can set up the 2020ppbPRO using an isobutylene calibration to mimic
the 2020ppbPRO response as if the 2020ppbPRO was calibrated using that specific
single compound.
General Information
In situations where only a single pure compound is present in air, the 2020ppbPRO
should be calibrated with a standard of that specific compound as span gas. The
2020ppbPRO
’s 15 memory slots can be used to store calibration information for 15
different span gases.
The 2020ppbPRO will always detect all ionizable compounds present in a sample
regardless of the response factor (RF) selected.
NOTE: Even if the 2020ppbPRO has been calibrated with a specific compound, its
response is not specific and the presence of another ionizable impurity may render
the numerical result invalid.
It is often impractical to carry a range of different standards into the field.
Approximate results can be obtained by calibrating the 2020ppbPRO with the
recommended span gas and entering the appropriate response factor. The
response factor is based on the ratio of the response of the specific compound to
the response of the span gas. The response factor multiplies the 2020ppbPRO
’s
reading, then displays and records it.