NAVI D-25 Instruction Manual page 57

2 Taking Measurements
2.7 Ion measurement (D-53)
● Measuring technique for increased accuracy
46
When the meter is in the Instantaneous Value
Measurement mode or the measurement value is on
HOLD in the Auto Hold Measurement mode, you can
store the measurement data by pressing the ▲ key. See
"3.1 Data memory function" page 65.
The input voltage range at which measurement is
possible using the meter is ± 800 mV. If measurements
do not work out satisfactorily, check the voltage during
mV measurement. Also, some samples are not
conductive to good measurement.
ION electrodes can be used to take a simple
measurement of ION concentration. For more accurate
measurement, however, certain techniques are required.
Refer to the electrode instruction manual or the
procedures explained below for more information.
① Adding ionic strength conditioner to sample
One source of measurement error is the influence of
ionic strength. Adjusting the ionic strength by adding
chemicals to the sample and standard solution for the
corresponding ION electrodes will result in accurate
measurements.
② pH effect of sample
The possible pH measurement range for each electrode
is determined by the type and construction of the ION
electrode. Check the pH value of each sample to
determine whether or not it is within the measurable
range. If the pH level is outside the measurable range,
modify the solution using chemicals containing ions
other than the ones being measured or ones that may
interfere with the measurement.
HORIBA