title: Electrochemical determination of water in environmental hydraulic fluids using the karl Fischer reaction.
abstract: Different procedures based on the Karl Fischer reaction were investigated with respect to their applicability for water determinations in environmental hydraulic fluids:  (i) continuous coulometry using a recently described diaphragm-free cell; (ii) on-line stripping of water at elevated temperature using either continuous coulometry or direct potentiometry for detection of the liberated water. Except for one of the oils, Statoil PA, which is a poly(α-olefin) with certain polymers added, no significant difference was found among coulometry using an optimized imidazole-buffered methanolic reagent containing 75% (v/v) chloroform, the two different stripping techniques (working in the temperature interval 100-110 °C), and the commercially available Hydranal Coulomat AG-H. The high stability and sensitivity of the coulometric technique described made it possible to work with sample amounts in the low milligram-range, and this is shown to increase the reliability of the coulometric method as compared to normally used procedures.
authors.affiliation: Department of Analytical Chemistry, Umeå University, S-901 87 Umeå, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Cedergren
authors.forename: M
authors.initials: M
authors.lastname: Lundström