Hanna Instruments HI 4101 - Manual (Page 12)

12
X. X. X. X. X. Quick Check of Electrode Slope Quick Check of Electrode Slope Quick Check of Electrode Slope Quick Check of Electrode Slope Quick Check of Electrode Slope
•
Connect BNC (connector) to pH/mV/ISE meter.
•
Place meter in mV mode.
•
Place 100 mL of deionized water into a vessel with
stir bar. Add 2 mL of ISA Hanna HI 4001-00.
•
Place sensor into prepared sample.
•
Add 1 mL of 1000 ppm or 0.1 M Ammonia standard
to beaker. Record the mV value when stable.
•
Add an additional 10 mL of standard to the solution.
Record the mV when reading has stabilized. This
value should be less than the previous noted (more
negative).
•
Determine the difference between the two mV values.
An acceptable value for this slope is 54±4 mV at
ambient temperatures between 20 and 25°C.
XI. XI. XI. XI. XI. Corrective action Corrective action Corrective action Corrective action Corrective action
•
Verify that the upper cap has been screwed in all the
way.
•
Verify electrode is connected properly to meter and the
meter is is powered.
•
Verify ISA has been added in the correct ratio to the
standard.
•
Examine the white membrane and check for electro-
lyte that might have leaked through the PTFE film.
Replace membrane if damaged.
•
If sensor does not change mV verify the the glass
assembly is operational (See section VIII).