Simultaneous determination of choline, carnitine and betaine in premixes by non-suppressed ion chromatography
A simple, highly sensitive ion chromatographic method for the simultaneous determination of betaine, choline and carnitine in feed premixes is described. Premixes were extracted via ultrasonication in water for 20 min and extracts were analyzed by ion chromatography using an aqueous 3.0 mmol L−1 methane sulfonic acid solution containing 15% (v/v) acetonitrile as the eluent and an IonPac SCS1 column. The composition of the mobile phase was optimized for the efficient separation of the three main analytes from each other as well as from common inorganic cations and trimethylamine, which is an ingredient for the synthesis of the analytes. The recoveries of choline, carnitine and betaine spikes added to premixes were all greater than 90% with replicate relative standard deviations of less than 10%. The limits of detection of this method for these analytes in premixes were calculated to be 10, 6 and 20 mg kg−1, respectively.