98
IMPORTANT
For better accuracy it is recommended to calibrate the instrument frequently.
Calibration should be performed whenever the pH electrode is replaced, after
performing a cleaning procedure or changing the reference electrolyte, and at
least once a month.
INITIAL PREPARATION
Pour small quantities of pH 7.01 (HI 7007) and pH 3.00 (HI 5003) solutions
into clean beakers.
For accurate calibration, use two beakers for
each buffer solution; the first for rinsing the
electrode, the second for calibration.
Note: The electrode should be submerged at least 4 cm (1½") into the solution.
PROCEDURE
Note: If you need to calibrate to NBS standards, use pH 6.86 (HI 7006)
solution instead of pH 7.01.
Use the supplied HI 98501 thermometer as reference.
• Switch the instrument on by pressing the ON/OFF
button.
• Rinse and immerse the pH electrode in pH 7.01 buffer
and shake briefly. Wait a couple of minutes for the
reading to stabilize.
• Note the temperature of the buffer solution using the
supplied HI 98501 thermometer (e.g. 20°C).
• Press the °C key to select temperature setting, then adjust the Temperature
knob until the LCD shows the noted temperature.
pH CALIBRATION
• Press the pH key to select pH measurement.
• Wait a couple of minutes, then adjust the OFFSET knob until the display
shows the pH value at the noted temperature (see the "pH versus
temperature" chart at page 10).
• Rinse and immerse the pH electrode in pH 3.00 buffer and shake briefly.
• Wait a couple of minutes, then adjust the SLOPE knob until the display
shows the pH value at the noted temperature (see the "pH versus
temperature" chart at page 10).
• The pH calibration is now complete.
4 cm
(1½")
HI 7007
RINSE
HI 7007
CALIBRATION
