Using analysed sample we have established that intensive homogenisation with a homogenisator or ultrasound device is the basic prerequisite for reproducible results.
The conditions for the coulometric water content calculation were tested, as crude oil requires a larger quantity of dissolution agent. Hydranal-Coulomat A already contains chloroform as a dissolution agent, but the tar contained in crude oil additionally requires xylene.
Coulometric titration is a cumulative method; the reagent is already dark after the first determination, making visual controls impossible. However, we have established that the results of the individual samples were reproducible, so that there were no indication problems.
Download the full Laboratory Report for Crude Oil (L 148) here