AMPEROMETRIC MEASUREMENT OF MOISTURE IN TRANSFORMER OIL USING KARL FISCHER REAGENTS

摘要

Moisture was measured in two oil Reference Materials (RMs), transformer oil (RM 8506) and mineral oil (RM 8507), by the volumetric and coulometric Karl Fischer methods, A variety of analysis conditions were used, including the solvent composition of the titration vessel, The maximum amount of moisture was obtained when the chloroform content of the titration vessel was above 65% after the solvent had been titrated to dryness, The highest moisture titers were measured by the volumetric method using either the Hydranal or pyridine-based Karl Fischer reagents or by the coulometric method using Hydranal AG-H reagent, Other coulometric reagents measured lower amounts of moisture even after the addition of organic solvents. Although the Hydranal AG-H recent measured moisture levels comparable to the volumetric reagents, it was necessary to correct the measurements for the reduced titration of the standard when using this reagent. The effect of the dissolution of the oil in the titration vessel solution was examined, When the oil is not completely dissolved in the titration vessel solution, it is capable of binding or sequestering a portion of the water so that the moisture is unavailable to react with the Karl Fischer reagent.