Hanna Instruments HI 902 Color, Quick Start Manual

Page: 209 / 248

Method ID: HI1005EN
Acidity of Water
0-2500 mg/L CaCO
3
, pH 8.3 Endpoint
Titrator Application Methods: General Methods - r. 2.3
Description:
Method for the determination of Total
(Phenolphthalein) Acidity in water by titration of a
sample to pH 8.3. The results are expressed in
mg/L (ppm) as Calcium Carbonate .
For the determination of Methyl Orange Acidity, set
the endpoint to pH 3.7.
Reference:
Standard Methods for the Examination of Water and
Wastewater 21
st
edition, Method 2310B.
Electrode :

HI 1131B Combination pH Electrode

HI 7662-T Temperature Probe
Reagents :

HI 70456 0.1N Sodium Hydroxide solution (1 L)

HI 70436 Distilled Water (1 gal)
Accessories :

HI 70300L Storage Solution (500 mL)

HI 7071 Electrode Fill Solution (4*30 mL)

HI 7004 pH 4.01 Buffer Solution (500 mL)

HI 7007 pH 7.01 Buffer Solution (500 mL)

HI 7010 pH 10.01 Buffer Solution (500 mL)

HI 740036P100-mL Plastic Beakers (10 pcs)

50-mL Class-A Volumetric Pipette
Procedure :

Connect the pH electrode and temperature probe
to the titrator.

Calibrate the electrode using pH 4.01, pH 7.01
and pH 10.01 buffer. Refer to the instruction
manual for calibration procedure.

Press “
Select Method
” from the main screen. Use
the arrow keys to highlight 'HI1005EN Acidity of
Water‟ and press “
Select
”.

Install a 25-mL burette with 0.1N sodium
hydroxide acid solution (HI 70456) on pump-one
and verify that no air bubbles are present in the
burette or tubing. If necessary prime the burette
until all air has been removed.
For the determination of the exact concentration of
the sodium hydroxide follow,
HI0001EN 0.1N
Sodium Hydroxide Titrant Concentration.

Use a class-A volumetric pipette to transfer
exactly 50.00 mL of sample to a clean 100-mL
plastic beaker.

Place the beaker under the stirrer assembly and
immerse the pH electrode, temperature probe and
stirrer. Ensure that the reference junction of the
pH probe is 5-6 mm below the surface.

Press “
Start
”. The titrator will begin the analysis

At the end of titration, when pH 8.30 is reached,
„titration completed‟ will appear with the acidity
concentration. The result is expressed in mg/L of
calcium carbonate .

Remove the electrodes and stirrer from the
sample and rinse them thoroughly with distilled
water.

Record the result.
Method Parameters :
Name: Acidity of Water
Method Revision: 2.3
Titration Type: Standard Titration
Analog Board: Analog 1
Stirrer Configuration: Stirrer 1
Pump Configuration:
Titrant Pump: Pump 1
Dosing Type: Dynamic
min Vol: 0.050 mL
max Vol: 0.500 mL
delta E: 5.000 mV
End Point Mode: Fixed 8.300 pH
Pre-Titration Volume: 0.000 mL
Pre-Titration Stir Time: 0 sec
Measurement Mode: Signal Stability
delta E: 1.0 mV
delta t: 2.0 sec
t-min wait: 2 sec
t-max wait: 20 sec
Electrode Type: pH
Blank Option: No Blank
Calculations: Sample Calc. by Volume
Dilution Option: Disabled
Titrant Name: 0.1N NaOH
Titrant Conc.: 0.1000 N (eq/L)
Analyte Size: 50.000 mL
Analyte Entry: Fixed
Maximum Titrant Volume: 25.000 mL
Stirring Speed: 1400 rpm
Potential Range: -2000.0 to 2000.0 mV
Volume/Flow Rate: 25 mL/50 mL/min
Signal Averaging: 1 Reading
Significant Figures: XXXXX
Calculations :
C
alculations: Sample Calc. by Volume
Titrant units: N (eq/L)
Titrant volume dosed: V (L)
Final result units: mg/L
Titrant conc.: 0.100 eq/L
(sample/titrant): 0.500 mol/eq
MW of sample: 100.09 g/mol
Sample volume: 50.000 mL
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