6
V.V.
V.V.
V.
Equipment Required:Equipment Required:
Equipment Required:Equipment Required:
Equipment Required:
• Hanna HI 4222 pH/ISE/mV meter or other suitable
ion or pH/mV meter. (Note: log/linear graph paper is
useful if an ISE meter is not available).
• Hanna HI 180 magnetic stirrer or equivalent with
stirring bars. (Note: Isolate beakers from stirrer motor
heat by placing insulating material such as foam or
cork between them).
• Hanna HI 4000-71 gas sensor test vessel or
Hanna HI 76404 electrode holder or equivalent with
Beakers or other suitable measurement vessel with
plastic sealing film or wrap.
VI. VI.
VI. VI.
VI.
Solutions Required for Calibration:Solutions Required for Calibration:
Solutions Required for Calibration:Solutions Required for Calibration:
Solutions Required for Calibration:
Ionic Strength Adjuster (ISA), 500 mL: HI 4005-00
Hanna 0.1 M standard, 500 mL: HI 4005-01
Hanna 1000 ppm CO
2
standard, 500 mL: HI 4005-03*
*Please Note: This calibration standards is ppm as CaCO
3
See Section XVII for additional solutions and accessories
used for maintenance.
Using volumetric pipettes and glassware prepare serial
dilutions of the standard. Select concentrations that will
approximately bracket the concentration of the samples to
be measured. Standards with concentrations less than
10
-3
M should be prepared fresh daily. Store solution in a
tightly sealed bottle without ISA added. 10 mL of HI 4005-
00 ISA should be added to each 100 mL sample of stan-
dard and samples just prior to measurement. ISA adjusts
the pH of the sample or standard to about pH 4.7 thus
converting carbonate and bicarbonate ion to carbon diox-
ide. It also provides samples and standards a constant
ionic strength background that stabilizes the solutions ac-
tivity coefficient and permits concentration to be measured
directly.
