ENMET Formaldemeter htV User Manual

Page 6

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ENMET Corporation

Formaldemeter htV

4

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.

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