PPM–400ST Formaldehyde Meter Operation Manual
A list of common chemicals that can cause
interference can be found in Appendix C or from the
manufacturer on request.
Phenol &
Resorcinol
The presence of phenol in the air can also cause
cross-interference on the
PPM–400ST
Formaldehyde Meter. When monitoring
formaldehyde in situations where phenolic resins
are used, the filters provided should be used. The
filters will completely remove phenols and other
substances from the sample at concentrations in
excess of 1000 ppm without affecting the
formaldehyde reading.
Filter Life
These fit on to the sampling port of the instrument.
Each filter should be used no more than ten times
and then discarded. Partially used filters should not
be stored in the vial with unused filters.
Replacement filters can be ordered from PPM
Technology or through your local distributor.
Sensor Background
Reading
Due to the high sensitivity of the sensor a
background reading can often be produced even
when sampling in an atmosphere considered to be
free of interference.
Humidity Extremes
As the sensor is very sensitive, it is possible that
extremes of humidity (generally, anything outside
the 40–60% R.H. range) may cause a background
reading. The PPM–400ST Formaldehyde Meter
is
specially designed to compensate for this problem
by using the humidity sensor and built-in data
analysis functions.
9
