Hanna Instruments HI 4221 - Manual (Page 33)

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ISE ISE ISE ISE ISE SETUP (HI 4222 SETUP (HI 4222 SETUP (HI 4222 SETUP (HI 4222 SETUP (HI 4222 only only only only only)))))
The ISE Setup menu allows the user to set the parameters regarding ISE measurement and calibration.
These parameters can be set specifically for each channel. The settings will be applied only to the active
channel.
Accessing ISE Setup
• Press
while in Measure mode and then to
select ISE range for the desired channel.
• Press and then to access ISE Setup menu.
To access an ISE Setup option:
• Use
or to highlight the desired option.
• Press to access the selected option.
The following is a detailed description of the ISE Setup option
screens.
Reading Mode
This option allows the user to select the desired reading mode: Direct, Direct/AutoHold, Known Addition, Known
Subtraction, Analyte Addition and Analyte Subtraction. Except Direct and Direct/AutoHold, all the other methods
are incremental (see ISE Theory section for details, page 54).
Direct
If using Direct reading mode, the ion concentration can be read directly from the instrument. Make sure the
instrument was calibrated before taking measurements.
Direct/AutoHold
If using Direct/AutoHold reading mode, the ion concentration can be frozen on the LCD after starting the AutoHold
mode.
Known Addition
In the Known Addition method a standard with a known concentration of the measured ion is added to the sample. The
difference in mV potential is then used to calculate the concentration of the ion in the sample.
Known Subtraction
In the Known Subtraction method a standard with a known concentration is added to the sample, reacting with the
ion to be measured. The stoichiometric ratio between standard and sample must be known. The ion concentration
is then calculated using the difference in mV potential.
The method is especially usefull when there is no available ISE for the measured ion.