Straightforward Determination of Alkaline and Alkaline-Earth Cations in Biodiesel by Ion Chromatography

A recent study performed by the Institute of Chemistry at the University of Campinas in Brazil has confirmed the excellent suitability of ion chromatography (IC) for quality control of biodiesel. More precisely, in this study sodium, potassium, calcium, and magnesium cations in biodiesel were quantitatively determined by IC using conductometric detection. The quality of the results was confirmed in terms of accuracy by analysing samples of the same kind by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) for comparison.

Pointing out one of their key findings, the authors state "that the proposed ion chromatographic method for the determination of Na+, K+, Mg2+ and Ca2+ in biodiesel offers statistically equivalent results to those of the ICP-OES procedure"

While the benefits of sophisticated methods such as ICP-OES for elemental analysis are acknowledged, the article continues to mention several inherent advantages of IC when it comes to the quality control of biodiesel. Thus the authors point out "… the relatively low cost of this analytical technique since it is not necessary to use expensive reagents or solvents or to consume specialty gases, while the equipment can be installed in a small space in the laboratory"

Summarising additional benefits of IC, the authors see further potential for ion chromatography stating that "due to its sensitivity and to the possibility of simultaneous multi-element determination, the ion chromatography method requires only small amounts of sample. The stability of the separation system, good selectivity and speed of analysis allow the range of IC applications to expand continuously."

The ion chromatographic analyses in this study were performed on a Metrohm 761 Compact Ion Chromatograph using a Metrosep C4 – 100/4.0 column.