Hanna Instruments HI 4101 - Manual (Page 32)

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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).