ASTM D6304 has been revised to include the Karl Fischer oven technique in order to address the challenges of determining the water content in lubricants, hydraulic oils, and other petrochemical samples can be a messy business.
The revised standard enables users to conveniently and accurately determine water content in multiple samples fully automatically by coulometric Karl Fischer titration – in which the oil matrix does not come into contact with the titration cell. Instead, the samples are introduced in single-use vials, which are put on the rack of an oven sample processor. Heating vial by vial, the water contained in the samples is evaporated. A constant stream of an inert carrier gas is used to bring the water fraction into the titration cell, where it is determined coulometrically. The sample matrix stays in the vials, which are disposed of after the titration.
Benefits include:
- No contamination of the KF titration cell
- No matrix interferences
- Less solvents needed
- Better reproducibility of results
- Automation possible for serial, completely unattended determination of multiple samples
QC laboratories from the petrochemical sector and contract laboratories facing high sample loads can use the Karl Fischer oven technique to increase efficiency of their routine analysis in compliance with the official standard. For more information, download the Metrohm Application Note.
