5
3
CHLOROPHYLL-A Measurement
3.1 Measurement
When powered on, the EM-400 will be in the measurement (read) mode (see figure
3).
The water sample can be transferred to the measurement cell using a pipette or filled
directly from a faucet, sample bottle, or sample valve.
The light shield should be in the closed position in order to measure CHLOROPHYLL-A.
Allow 5 seconds for the EM-400 to reach stable CHLOROPHYLL-A readings. For a
sample containing 100 ppb CHLOROPHYLL-A, the measured CHLOROPHYLL-A should
be stabilized within the range of 98 to 102 ppb.
The EM-400 does not need to be turned off between measurements of two samples.
Rinsing the measurement cell several times is recommended.
3.2 High Color and Turbidity Warning
The EM-400 has extra channels to measure sample turbidity and color to
automatically compensate sample color and turbidity interference. If sample turbidity
and color values determined are too high, a CHLOROPHYLL-A measurement warning
will be displayed. In such a case, the user should dilute the sample for CHLOROPHYLL-
A measurement.
