Interferences - ION MVI User Manual

When using the instrument, it is important to remember that Mercury is heavier than air and therefore samples
should be drawn from ~1 foot (30 cm) from ground.
After use, switch the instrument OFF and recharge the batteries if necessary. Please remember the MVI may not
operate correctly when LO BAT is indicated on the display.

Interferences

The MVI detector operates on the principle of UV light absorption. There are substances other than mercury which
also cause light absorption and these substances are known as interference vapours.
Some of the interference vapours encountered are various hydrocarbons, water vapour, sulphur compounds and
particles such as smoke. There is no measurable interference from carbon monoxide, carbon dioxide or ammonia. A
large change in humidity will cause readings of between 5 to 10 µg/m³. The MVI is zeroed at the site of measurement
away from sources of mercury to avoid this.
Table of some interferences at 100 ppm concentration:
Compound
Benzene
Toluene
Acetone
Ethyl Alcohol
Ethyl Acetate
Pioneering Gas Sensing Technology.
Reading in µg/m³
20
3.5
3.0
6.0
3.0
Page 15 of 19
MVI Instrument User Manual V2.4
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