27
It is recommended to calibrate the instrument frequently, especially if high
accuracy is required.
The ISE range should be recalibrated:
• Whenever the ISE probe or ion charge is changed.
• At least once a week.
• After testing aggressive chemicals.
• When calibration alarm time out is expired-
“CAL DUE”
tags blinks (if
feature is enabled).
Due to electrode conditioning time, the electrode must be kept immersed a few
seconds to stabilize. The user will be guided step by step during calibration
with easy to follow tags on the LCD. This will make the calibration a simple and
error-free procedure.
PROCEDURE
Select the proper ISE probe in SETUP menu (only for
HI 98185
) or select the
proper Ion Charge (see SETUP for details, page 33).
Note:
If ISE probe is not calibrated in at least one point, the
“----”
will be
displayed.
Pour small quantities of the buffer solutions into clean beakers. If possible, use
plastic beakers to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use two beakers for
each standard solution. One for rinsing the electrode and one for calibration.
The instrument offers a choice of six memorized standard solutions: 0.1, 1, 10,
100, 1000, 10000 ppm and calibration up to five points. For fluoride
electrode the 2 ppm standard is also available (
HI 98185
only).
Remove the protective cap from the ISE electrode.
FIVE-POINT CALIBRATION
• Immerse the ISE electrode approximately 4 cm (1½”)
into the less concentrated standard solution and stir
gently.
IIIIIS E
S E
S E
S E
S E CALIBRATION
CALIBRATION
CALIBRATION
CALIBRATION
CALIBRATION
(HI 981
(HI 981
(HI 981
(HI 981
(HI 98184 &
84 &
84 &
84 &
84 & HI 981
HI 981
HI 981
HI 981
HI 9818 5
8 5
8 5
8 5
8 5)))))
