Analysis of E-85 Fuel for Formic, Acetic, Propionic, Butyric, Glycolic and Citric Acids using Reversed Phase High Performance Liquid Chromatography

An HPLC (High Performance Liquid Chromatography) method to measure the concentration of six organic acids in E-85 fuel has been developed. A three point calibration curve is established using standard solutions of the following organic acids: formic acid, acetic acid, propionic acid, butyric acid, glycolic acid and citric acid. An internal standard (maleic acid) is used to monitor HPLC system suitability and peak retention time stability. The method utilizes UV detection at 210 nm to detect and quantify the levels of each acid in E-85 fuel. Test results from nine commercially available E-85 fuel samples are reported.

Analytical method validation was achieved by performing and confirming system suitability or injection repeatability (percent relative standard deviation ≤ 3%), calibration curve linearity (R² ≥ 0.999), analysis repeatability (standard deviation < 1 mg/L) and recovery (percent recovery 91 - 102%). The minimum detectable level was determined to be less than 1.5 mg/L for each acid.