22
The available options are:
Save Profile
:
save the current profile.
Save Profile As...
:
save current profile using a specific name.
Load Profile
:
load from available profiles.
Delete Profile
:
delete a profile.
Save Current Profile
To save the current profile:
• Use
or
to select Save Profile As...
• Press
. The
Text Editor
box will be displayed on the LCD.
• Enter the desired profile name by using
and
to highlight the desired character and then press
to add it to the text bar. It is also possible to delete the last character by positioning the cursor on the
Backspace character ( ) and pressing
.
• Press
to return to the Profile options.
• Use Save Profile to save changes made to a presently used Profile. Changes will overwrite existing configurations.
• Select Load Profile to select a profile to use from the list of saved profiles. Highlight the desired profile and
press
.
• Select Delete Profile to remove a selected profile from the saved list.
Highlight the profile and press
.
Temperature
The temperature has a direct influence on pH. This option allows the user to choose the temperature source and
units, as well as the desired manual temperature for manual temperature compensation mode.
Temperature Source
(
HI 5222 only
)
If using a temperature probe, Automatic Temperature Compensation will be performed relative to the displayed
temperature, with the “
ATC
” indicator displayed on the LCD. For the
HI 5222
, one temperature probe can be used
for both measurement channels if desired. Select the source by selecting Manual, Channel 1 or Channel 2 . If no
temperature probe is detected, Manual Temperature Compensation will be performed, with the “
MTC
” indicator
on the LCD.
Temperature Unit
The desired temperature unit can be chosen (Celsius, Fahrenheit or Kelvin degrees) and the meter will automatically
make the conversion for 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 pH measurement.
59
ANALYTE SUBTRACTION
To measure the concentration of a sample using Analyte Subtraction method:
• Press
and then
to select
ISE Measure
mode for the selected channel.
• Select the Analyte Subtraction method (see ISE Setup
→
Reading Mode).
• Prior to starting an AS procedure, the ISE sensor must be calibrated with a minimum of two standards
containing ISA. The slope of the electrode will be used in all calculations involved in AS.
• If following an established procedure: Press
then edit the method variables and follow the
procedure below.
• Press
to set the method parameters. Press
/
to select next/previous parameter
to edit, then press
and use
or
to set the desired parameter value. Press
to save the modified value and then press
to exit method parameters edit menu.
• If developing a procedure: Before attempting Analyte Subtraction analysis, it is important to determine
which sample volume, Reactant volume and concentration, will produce the best results and the way the
Reagent will react with the measured Ion on a molar basis (Stoichiometric factor). As a general rule, the
reactant should contain the measured Ion so the sample addition will react with the Ion and reduce the
measured concentration of the sample. The change of the mV value, before and after the sample
addition, should be at least 10 mV. Start with a small trial. For example: Measure 50 mL of reactant,
add a magnetic stir bar and place on a stirrer, add ISA (consult ISE manual) and place ISE electrode tip
into the sample. Put instrument in mV mode and record the observed mV. Using a micropipet, add a
volume of the sample. Start by adding 500 µL at a time (for example) Watch the change in mV. When
you have observed approximately a 10 mV change from the original value, calculate the total volume
added. Adjust sample and standard volumes proportionally to standard volumes that can be measured
with accuracy. Use volumetric pipettes for standard, ISA and sample addition.
• Press
then edit the procedure variables to the volumes determined in the prior step.
Procedure:
• Press
to enter Analyte Subtraction mode.
• Volumetrically add Reactant to a clean beaker. Add Stir bar and place on a magnetic stir plate. Stir
standard. The method will prompt user to add ISA. Place ISE sensor tip into the solution and a mV value
will show on the display.
• Press
to take the first mV reading.
• When the reading is stable, press
to store the first mV reading. The second step of the method
will be displayed on the LCD in which the user is notified to add the Sample Volume to the standard
solution.
• Press
to take the second mV reading.
