Ion Chromatographic Determination of Organic Acids in Food Samples Using Permanent Coating Graphite Carbon Column and Mobile Phase with Benzoate

Abstract

From the viewpoint of a graphite carbon column with excellent durability, it was applied to the ion chromatography (IC) of several organic acids. The carbon column was permanently coated with the cetyltrimethylammonium ion, and the elution behaviors of several organic acids (acetic acid, lactic acid, succinic acid, malic acid, tartaric acid, citric acid) and inorganic anions (Cl−, NO2−, NO3−, SO42−) were examined according to an ion chromatography that combined conductivity detector using a mobile phase of the benzoic acid system, when an ion-exchange ability was given to the graphite carbon column. Tartaric acid and citric acid, etc. with large valency showed tendency to which the width of each peak extended and the retention time increased. However it was possible to separate excellently for the analytes detected within ten minutes. The calibration curves obtained from the peak areas for the organic acids and inorganic anions were linear, with good correlation coefficients of 0.999. The relative standard deviations (RSD) of the peak areas were between 0.4 and 1.0 for six repeated measurements. The developed method was then applied to the determination of organic acids in several food samples.