ENMET Formaldemeter htV - Manual (Page 6)

ENMET Corporation Formaldemeter htV
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3.2 Interferants
3.2.1 Phenol & Resorcinol
The presence of phenol in the air can give a reading on the Formaldemeter
™ htV. When monitoring formaldehyde in
situations where phenolic resins are used, the phenol filters provided should be used. These fit on to the sampling port of the
instrument. The filters will completely remove phenols from the sample even at concentrations in excess of 1000 ppm without
affecting the formaldehyde reading.
3.2.2 Phenol filter life
Each filter should be used no more than five times and then discarded. Partially used filters should not be stored in the vial with
unused filters. Replacement filters can be ordered from through your local distributor.
3.2.3 Alcohols & Aldehydes
As is found with other portable detection equipment, the meter is not totally specific to formaldehyde alone, being susceptible
to a degree of interference from a small range of other chemicals. Other aldehydes and alcohols such as methanol and ethanol
in the atmosphere can cause cross-interference effects.
Table 1: Relative Response of the Formaldemeter
™ htV
to Various Compounds in the Vapor Phase
Compound Concentration Required
to Give Reading of 1 PPM
Comments
Acetone No response
Acetaldehyde 8 – 12 Linear response similar to that for
Ethanol
Acetic Acid No response
Ammonia 71000 Response only at very high
concentration
Butanol Very little interference (See note)
Carbon Monoxide 100 Linear response
Ethylene 160
Ethanol 12 – 20 Linear response
Formaldehyde 1.0
Glutaraldehyde 7100 at 25°C
Methanol 50 Linear response
Phenol 5 Can be completely removed with filter
provided
Propanol Very little interference(See note)
Resorcinol 5 Can be completely removed with filter
provided
N OTE : Propanol and Butanol are only likely to interfere at high temperature (greater than 60°C) and high concentration (higher
then 20 ppm).
3.3 Sensor Background Reading
Due to the high sensitivity of the sensor and the widespread occurrence of formaldehyde in the indoor environment, a
background reading of up to 0.05 ppm can often be produced, even when sampling in an atmosphere considered to be free of
formaldehyde or other contaminants.