Development of Karl Fischer Reagents
Development of Karl Fischer Reagents
Development of Karl Fischer Reagents
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III-2. Foodstuffs<br />
(2) Moisture vaporization - Volumetric titration<br />
<strong>Reagents</strong> used: <strong>Karl</strong> <strong>Fischer</strong> Reagent SS-Z (or SS)<br />
Dehydrated Solvent GEX (or MS) + PG (3:1) 50-100ml<br />
174<br />
Substance<br />
Soup powder<br />
Wasabi paste<br />
Soy sauce<br />
Mayonnaise<br />
Heating Temperature<br />
( � C)<br />
090<br />
110<br />
200<br />
200<br />
Sample Quantity<br />
(g)<br />
0.0824<br />
0.0522<br />
0.0399<br />
0.1408<br />
(3) Moisture vaporization - Coulometric titration<br />
<strong>Reagents</strong> used: Aquamicron AX (or AS) 150ml<br />
Aquamicron CXU 10ml<br />
Sugar<br />
Spices<br />
Substance<br />
4. Confectionery<br />
Key Points<br />
Heating Temperature<br />
( � C)<br />
130<br />
130<br />
Sample Quantity<br />
(g)<br />
0.4853<br />
0.0412<br />
Measurement Value<br />
(mg)<br />
03.70<br />
11.68<br />
24.07<br />
28.61<br />
Measurement Value<br />
(µg)<br />
3669<br />
5830<br />
Moisture Content<br />
(%)<br />
04.49<br />
22.40<br />
60.30<br />
20.30<br />
Moisture Content<br />
(%)<br />
01.98<br />
14.20<br />
Because sugar is the main ingredient <strong>of</strong> confectionery, these items are<br />
dissolved in a sugar-type dehydrated solvent for titration. Volumetric<br />
titration is used.<br />
Coulometric titration is normally avoided as these products will not<br />
dissolve in electrolytes. The moisture vaporization method is also in<br />
some cases unsuitable as heating causes sugars to break down and<br />
produce water.<br />
Caramels, candies and similar items are titrated after they have been<br />
dissolved in a sugar-type dehydrated solvent that has been heated (up<br />
to 45 � C). (If the temperature exceeds 45 � C the formamide in the sugartype<br />
dehydrated solvent will gradually break down. The <strong>Karl</strong> <strong>Fischer</strong><br />
reagent will be consumed in small amounts and this will lead to<br />
uncertainty about the end point.) The moisture vaporization method can<br />
be used for snack-type confectionery.
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