Water content in petroleum

products and additives

Oven method as per ASTM D6304 makes coulometric Karl Fischer titration easier than ever Highlights

• Less solvents needed

• Better reproducibility of results

• Walk-away automation for multiple samples





The standard method has become much easier 02

Do you use coulometric titration to determine water content in petrochemical samples and have to comply with ASTM

D6304? If so, you are probably all too aware that there are some challenges:

• Poor solubility of highly viscous samples such as lubricant oils, hydraulic oils, etc.

• Frequent cleaning of the titration cell required

• Side reactions due to the presence of additives in the sample

• Considerable amounts of solvents required All of these disadvantages negatively affect cost efficiency and performance of your analysis.

Revised ASTM D6304 includes automated oven method Addressing the mentioned challenges, ASTM has revised Heating vial by vial, the water contained in the samples is method D6304. The standard method now includes the evaporated. A constant stream of an inert carrier gas is oven method: Here, the sample matrix does not come used to bring the water fraction into the titration cell, into contact with the titration cell at all. Instead, the where it is determined. The sample matrix stays in the vi-samples are introduced into single-use vials, which are put als, which are simply disposed of after the titration.

on the rack of an oven sample processor.

The benefits of this method are considerable

• No contamination of the KF titration cell

• No matrix interferences

• Less solvents needed

• More reliable analysis and better reproducibility of results

• Automation possible for serial, completely unattended determination of multiple samples





874 Karl Fischer Oven

Sample Processor – fully automated determination of water content

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in up to 35 samples

Using the 874 Karl Fischer Oven Sample Processor you can analyze the water content in up to 35 samples fully auto-matically. Place the vials on the rack, start the method, and dedicate your valuable time to other tasks in the lab.

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Principle of the method

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At the heart of the 874 Karl Fischer Oven Sample Processor is an oven. In the heating chamber of this oven, the sample is heated. As a result, the water in the sample evaporates. The water fraction thus released from the sample is carried by an inert carrier gas into the Karl Fischer titration cell, where the water is titrated.

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1 Dry carrier gas

2 Carrier gas with the released moisture 3 Hollow outlet needle

4 Hollow inlet needle

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5 Septum closure

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6 Sample

7 Oven



www.metrohm.com

ohm, published November 2019

8.000.5329EN by Metr