Simultaneous quantitative analysis of the acetate, formate, chloride, phosphate and sulfate anions in biodiesel by ion chromatography

A quantitative ion chromatographic analytical method for the simultaneous determination of the acetate, formate, chloride, phosphate, and sulfate anions in biodiesel is proposed. Samples of biodiesels prepared from soy, canola and sunflower vegetable oils, from crude soy oil, and from bovine fat were analyzed. The extraction of the anions from the matrixes was performed using water with the assistance of ultrasound. The observed limits of detection and of quantitation in mg kg−1 and the mean relative standard deviation in percent were, respectively: acetate, 0.32, 0.97 and 4.4; formate, 1.36, 4.12 and 6.2; chloride, 0.098, 0.30 and 6.5; phosphate, 0.81, 2.47 and 7.1; and sulfate, 0.087, 0.264 and 7.8. The procedure can be considered to be green because it uses small volumes of water, is simple, and can be performed rapidly.