Hanna Instruments HI 903 - Manual (Page 177)

Method ID: HI8104EN
Surface Moisture Determination on White Sugar
Titrator Application Methods: General Methods - r. 0.4
Description:
Method for the determination of the surface moisture
content of white sugar. The results are expressed in
ppm and should be between 250 and 350 ppm.
Electrode:

HI 76320 Double Platinum Pin Electrode
Reagents:

1 mg/mL One-Component KF Volumetric Titrant

Dry Methanol

Dry Chloroform
Other Accessories:

A clean, dry weigh boat

GL 45-Thread Solvent Bottle
Procedure:

Setup titrator according to the instruction manual.
 Press “Select Method” from the main screen. Use
t
he arrow keys to highlight ‘HI8104EN Surface
Moisture - Sugar ’ and press “Select”.

Install a 5-mL burette filled with 1 mg/mL One-
Component KF Volumetric Titrant and verify that
no air bubbles are present in the burette or tubing.
If necessary prime until all air has been removed
completely.
For the determination of the exact concentration of
the titrant follow HI8003EN 1.0 mg/mL Titrant
Standardization using Liquid Water Standard.

Prepare at least 200 mL of solvent by adding 2
parts dry chloroform to 1 part dry methanol in a
solvent bottle. Attach the solvent bottle top
assembly to the bottle according to the instruction
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 weigh boat with 7.5 to 10 g of sample.

Weigh the weigh boat and sample.
 Press “Start Analysis”. You will be prompted to
enter the sample size.

Remove the sample port and use the weight boat
to transfer the solid sample into the titration
vessel. Replace the sample port plug as quickly
as possible to prevent humidity from entering the
titration beaker. Pay attention not to get any
sample on the electrode or beaker walls. If
necessary swirl the titration vessel by hand.

Weigh the weigh boat again in order to determine
the added sample 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 “Sample Analysis
Result” screen is displayed. The results are
expressed in ppm of water.

Use fresh solvent after every 2 to 3 titrations.
Method Parameters:
Name: Surface Moisture - Sugar
Method Revision: 1.0
Type: Sample Analysis
Predispensing Amount: None
Pre-Analysis Stir Time: 120 Sec
Stirring Speed: 900 RPM
Stirbar Type: Medium
Drift Entry: Automatic
Solvent: CHCl3 MeOH 2:1
Sample Parameters:
Sample Determ.: Normal
Sample Name: Sugar
Sample Type: Mass
Sample Size: 7.5000 g
Titrant: Composite 1
Titrant Type: One Component
Nominal Titrant Conc.: 1.0000 mg/mL
Std. Titrant Conc.: 1.0000 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: 1.000 uL
Maximum Dose: 30.000 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: 900 sec
Maximum Titrant Volume: 10.0000 mL
Term. Criterion: Relative Drift
Relative Drift: 20.0 ug/min
Result Unit: ppm
Calculations:
Calculations:
Titrant units:
mg/mL
Titrant volume consumed: V (mL)
Final results units: ppm
Titrant concentration: 1.0000 mg/mL
Sample mass: 7.5000 g