Analysis of Biodiesel and Diesel

Metrohm presents its new instrument ­Metrohm 873 for analysis of diesel and biodiesel. During the measurement a stream of air is passed through the sample, contained within a sealed and heated reaction vessel. These conditions accelerate the rate of oxidation of the fatty acid methyl esters in the sample, with peroxides being initially formed as the primary oxidation products. After some time the fatty acid methyl esters disintegrate completely. The second oxidation products formed include low-­molecular organic acids. These are transported in a stream of air to a vessel containing distilled water. The conductivity in this vessel is recorded continuously. The ­organic acids can be detected by the increase in conductivity.