Coulometric microdetermination of water.
An electroanalytical method for the determination of small amounts of water by controlled potential coulometry has been devised. Excess of iodine is produced coulometrically in a Karl Fischer reagent, the sample is added, and after complete reaction the remainder of the iodine is reduced. The number of coulombs consumed in the cell reaction is determined by integration of the current by means of an electronic integrator. Karl Fischer reagents of various compositions were checked to find the most satisfactory conditions and a special electrolysis cell for water determination was constructed entirely in glass and Teflon. Samples containing 0.1-2 mg of water were added and determined with an accuracy of +/- 0.15 %. The analysis times were 3-12 min.
Karlsson
R
R
Department of Analytical Chemistry, Chemical Center, University of Lund, S-220 07 Lund 7, Sweden.
Karrman
K J
KJ