Hanna Instruments HI 903 - Manual (Page 163)

Method ID: HI8001EN
5.0 mg/mL Titrant Standardization using a Liquid Water Standard
for one-component titrant
Titrator Application Methods: General Methods - r. 0.4
Description:
Method for the standardization of 5.0 mg/mL One-
Component Karl Fischer Titrant using a Liquid Water
Standard. The results are expressed in mg/mL.
Electrode:

HI 76320 Double Platinum Pin Electrode
Reagents:

5 mg/mL One-Component KF Volumetric Titrant

10 mg/g Liquid Water Standard

Dry Methanol
Other Accessories:

A clean, dry 3-mL syringe

A clean, dry 22-gauge , 6” non-coring septum
penetration needle

GL 45-Thread Solvent Bottle
Procedure:

Setup titrator according to the instruction manual.
 Press “Select Method” from the main screen. Use
the arrow keys to highlight ‘HI8001EN Stdz
5mg/mL w/ water Std.
’ and press “Select”.

Install a 5-mL burette filled with 5 mg/mL One-
Component KF Volumetric Titrant to be
standardized and verify that no air bubbles are
present in the burette or tubing. If necessary prime
until all air has been removed completely.

Connect the solvent bottle top assembly to the
bottle of methanol according to the manual.

Prepare the titration vessel according to the
manual. Dispense enough solvent from the solvent
bottle to fill the vessel to the “min” line (about 50
mL).
 Press “Start/Stop” to pre-titrate the solvent and the
titration vessel moisture. Allow the background
drift rate to stabilize before proceeding to the next
step.

Fill the syringe and needle with the water
standard.

Weigh the syringe, needle and water standard.
 Press “Start Analysis”. You will be prompted to
enter the sample size.

Dispense 1.00 g (about 1 mL) of standard into the
titration vessel through the septum using the
needle. Pay attention not to get any sample on
the electrode or beaker walls. If necessary swirl
the titration vessel by hand.

Clear the needle of residual standard by intaking a
small volume of air from the titration vessel. If a
“hanging drop” of standard is seen on the end of
the needle, dip the end of the needle briefly in the
solvent.

Remove the needle from the titration vessel and
weigh the syringe again in order to determine the
added standard mass (by difference of the two
measurements.)

Use the numeric keypad to enter the exact weight
and press “Enter” to start the analysis.

At the end of the titration, the “Standardization
Result ” screen is displayed. The results are
expressed in mg/mL.
Method Parameters:
Name: Stdz 5mg/mL w/ water Std
Method Revision: 1.0
Type: Titrant Standardization
Predispensing Amount: 25 %
Pre-Analysis Stir Time: 5 Sec
Stirring Speed: 900 RPM
Stirbar Type: Medium
Drift Entry: Automatic
Solvent: Methanol
Standard: Liquid 10 mg/g
Type: Liquid by mass
Concentration Unit: mg/g
Water Content: 10.0000 mg/g
Standard Size: 1.0000 g
Titrant: Composite 5
Titrant Type: One Component
Nominal Titrant Conc.: 5.0000 mg/mL
Std. Titrant Conc.: 5.0000 mg/mL
Date/Time: Jan 1, 2011 12:00
Titrant Age Reminder: 2d:00h:00m
Control Parameters:
Start Mode: Normal
Standby Mode: Enabled
Standby Duration: 720 minutes
Imposed Current: 20 uA
Minimum Dose: 0.500 uL
Maximum Dose: 20.000 uL
Timed Increment: 1 second
End Point Value: 180.0 mV
Signal Averaging: 3 Readings
Flow Rate: 10.0 mL/min
Termination Parameters:
Maximum Duration: 1200 sec
Maximum Titrant Volume: 10.0000 mL
Term. Criterion: Relative Drift
Relative Drift: 7.0 ug/min
Calculations:
Titrant units: mg/mL
Titrant volume consumed: V (mL)
Final Results Units: mg/mL
Standard Concentration: 10.0000 mg/g
Standard mass: 1.0000 g