The sample,
containing a maximum of 100 mg of water, is dissolved or dispersed
in a suitable liquid and titrated with KF reagent, which consists of
iodine, sulfur dioxide, organic base, and a solvent (typically an
alcohol, such as methanol, ethylene glycol, or 2-methoxyethanol).
The titration end point is determined amperometrically with a
platinum electrode which senses a sharp change in cell resistance
when the iodine is reduced by sulfur dioxide in the presence of
water. |
