12
X. X.
X. X.
X.
Quick Check of Electrode SlopeQuick Check of Electrode Slope
Quick Check of Electrode SlopeQuick 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 actionCorrective action
Corrective actionCorrective 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).
