Development of Karl Fischer Reagents

III-1. Industrial Products
(3) Gradually open valve B while stirring the anolyte (or general-use
dehydrated solvent). Inject the sample for 10-15 minutes (at a rate of
about 1g/min.).
140
Note:The sample will gasify as it is injected and it will escape through
the upper vent valve into a draft chamber, or to the outside air.
(4) Withdraw the syringe from the sampling bottle.
(5) Weigh the sampling bottle. Subtract this weight from the weight before
the injection of the sample to determine the weight of the sample.
(6) Titrate the moisture absorbed into the anolyte (or general-use
dehydrated solvent) to the end point, using coulometric titration
(volumetric titration).
(7) Calculate the moisture content using the following formulae.
For coulometric titration:
Moisture content (ppm) = measurement value (µg)/sample quantity (g)
For volumetric titration
[Examples of Measurement]
(1) Volumetric titration
Reagents used: Karl Fischer Reagent SS-Z (or SS)
Dehydrated Solvent GEX (or MS) 100ml
Substance
LPG
Propane
Methyl chloride
Vinyl chloride
Sulfur dioxide
Aerosol
Moisture content (ppm) =
Sample quantity
(g)
25.1
29.0
18.3
15.7
53.1
27.4
Titration quantity
(mg)
1.40
1.11
4.95
7.41
17.6
1.18
(2) Coulometric titration
Reagents used: Aquamicron AX (or AS) 150ml
Aquamicron CXU 10ml
Titration volume(ml)�Titer(mgH2O/ml)
�100
sample quantlty (g)�1000
Moisture content
(ppm)
56
38
271
475
331
35