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Known Subtraction
In the Known Subtraction method, a sample is measured with an ISE before and after the addition of a known
volume of a reactant standard. The reactant standard reacts with the measured Ion in the sample, reducing it’s
concentration. The mV difference is then used to calculate the concentration of the Ion in the original sample. The
stoichiometric ratio between Reactant Standard and Ion in the sample must be known.
Analyte Addition
Analyte Addition is similar to the Known Addition method, with the difference being that an aliquot of sample is
added to a known volume of standard. Both solutions contain the same measured ion. The standard is measured
with an ISE before and after the addition of a known volume of a sample. The Ion concentration is then calculated
using the difference in mV potential. The sample should increase the concentration of the Ion being measured.
Analyte Subtraction
In the Analyte Subtraction method, an aliquot of sample is added to a reactant standard of known concentration
and volume. The sample partially reacts with the measured ion. The stoichiometric ratio between standard and
sample must be known. The Ion concentration is then calculated using the difference in mV potential.
To set the Reading Mode:
• Press
while in
ISE Measure
mode.
• Press
.
• Use
or
to select the Reading Mode option.
• Press
and use
or
to highlight the
desired option.
• Press
to confirm your selection or press
to
cancel operation.
Temperature
This option permits the user to configure all parameters related to
ISE temperature measurements.
Temperature Source
The options are Manual, Channel 1 or Channel 2. If no temperature
probe is detected, a Manually set value will be displayed (and
logged) with the measurement. If a temperature probe is connected
to either channel, it may be selected. The temperature measurement
will be displayed and logged with the measurement and may be
used for temperature compensation calculation if Temperature
Compensation is enabled.
Temperature Unit
Select the desired temperature unit (Celsius, Fahrenheit or Kelvin degrees) and the meter will automatically
convert to the selected unit.
Manual Temperature
If no temperature probe is connected, the desired temperature can be set manually. The default setting is 25 °C.
If the measured temperature is different, the value can be manually adjusted to obtain an accurate Ion measurement.
Temperature Compensation
ISE measurements benefit from temperature compensated corrections if:
• standards and sample temperatures differ from each other
• the Isopotential Point of the ISE is known.
If sample and standards are made at the same temperature, leave this option disabled.
Isopotential Point
If the Temperature Compensation is enabled, the isopotential point
of the ISE must be added in this parameter. Verify the
Electrode Type
and
Concentration Unit
are configured for the desired application.
The Isopotential point will use the selected concentration unit. Use
and
to edit the isopotential point value and press
to save the value or press
to cancel operation.
Notes
:
• A warning message will appear on the LCD informing the user to
perform a new calibration.
• A minimum of two Ion standards is required for the ISE calibration.
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