Abstract: A high pressure coulometric titration apparatus features a pressure vessel for containing a titration vessel, which is capable of being subjected to a pressure above the vaporization pressure of the sample to be analyzed. A back pressure regulator is employed to maintain the internal chamber created by the pressure vessel at this predetermined pressure level, so that the sample will remain in a liquid phase throughout the analysis. A fluid control arrangement is also provided for sweeping the chamber with a dry, inert gas, as well as conveying a predetermined amount of the sample to the titration vessel. This fluid control arrangement in combination with the pressure vessel operates to insure that all of the water in the sample will be trapped in the solvent, as well as to prevent the introduction of extraneous water into the system.