Water content determination of bioethanol by Karl Fischer Titration

Bioethanol is mixed with gasoline in various ratios in order to reduce both the demand for gasoline and environmental pollution. The gasoline-alcohol mixture is known in the USA as gasohol and in Brazil as Gasolina Tipo C. In the USA the mixtures E10 and E85, which contain 10% and 85% bioethanol respectively, are widespread. In Brazil the bioethanol content of most mixtures lies between 21% and 23%.

The ASTM standard E 1064 «Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration» describes the coulometric Karl Fischer titration for determining the water content.

For a water content >2% the recommended test method is volumetric Karl Fischer titration as per ASTM E 203. The volumetric KF titrators from Metrohm meet all the specifications required by the standard and are therefore extremely suitable for this application.

Volumetric Karl Fischer Titration by Metrohm

An additional option is reagent exchange using an automated dosing device. The KF vessel does not have to be opened during this procedure. This means that no hazardous reagents have to be handled, which results in increased operator safety.

Product information

• Coulometric Karl Fischer Titrators by Metrohm
• Brochure: Quality Assurance of Biofuels with Metrohm instruments (pdf)
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