A Novel Chemical Method for Determining Ester Content in Biodiesel

Ester content in the biodiesel plays an important role in evaluating the biodiesel quality. Gas chromatography method has proven as the most significant method for determining the ester content till now. Present study proposed a new testing method for investigating the ester content in biodiesel through the content of total glycerol in biodiesel. As per mechanism of transesterification reaction, one mole glycerol is produced from one mole triglyceride in a large excess of alcohol and catalyst. The remaining content of triglycerides can be proximate calculated from the content of total glycerol and then ester content can be converted proximately by subtracting the content of remaining triglycerides from 100 wt.%. This research work introduces a novel procedure for determining the total glycerol and ester content in biodiesel. This method is applied on several samples, and the results are compared with results of gas chromatography method as per the standard EN 14103 guidelines. The results show that the new method gives results comparable to the result from gas chromatography analysis. There is fair agreement between both methods with coefficient of correlation of 0.98. This methodology uses simple laboratory equipment and can also apply for biodiesel from various feedstock oils.