Page 461 - Applied Pharmacognosy
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• The sample or the powdered material is first exhausted
of water with a suitable anhydrous solvent (dioxan) and
an aliquot is taken for estimation of moisture.
• The Karl fischer reagent consists of a solution of: iodine , sulphur
dioxide and pyridine in anhydrous methanol.
•
• The reagent is dark brown in colour.
•
• The reagent is titrated against a sample containing water.
• The water causes a loss of the dark brown colour of the reagent.
•
