Development of Karl Fischer Reagents

III-3 Pharmaceuticals
(4) Moisture vaporization - Coulometric titration
Reagents used: Aquamicron AX (or AS) 150ml
Aquamicron CXU 10ml
184
Substance
Albumin
Glutathione
Berberine chloride
Bufferin
Aspirin aluminum
Synthetic penicillin
Heating Temperature
( � C)
110
110
150
130
150
150
Sample Quantity
(g)
0.1818
0.4208
0.0288
0.0662
0.1715
0.0837
Measurement Value
(µg)
0578
1635
2735
2645
2332
2616
Moisture Content
(%)
0.318
0.389
9.560
4.000
1.360
3.130
3. Chinese Herbal Medicines, Biological Tissue, etc.
Key Points
Either a general-use or a sugar-type dehydrated solvent is used for
chinese herbal medicines. In general, however, these products are
difficult to dissolve. This means that insufficient moisture is extracted
and accurate analytical results cannot be obtained. The moisture
vaporization method is used for this reason. The heating temperature
must be considered carefully as heating can cause some products to
change color or break down.
In the examples shown, biological tissue was dispersed in a generaluse
dehydrated solvent and subjected to Karl Fischer titration.
Similar procedures should be used for capsules and other items.
[Examples of Measurement]
(1) Volumetric titration
Reagents used: Karl Fischer Reagent SS-Z (or SS)
Dehydrated Solvent GEX, SU (or MS, FM) 25-50ml