Organic acids and their salts such as citric, malic, formic, lactic, acetic, propionic, and fumaric acids are animal feed additives that play an important role by improving the animals’ performance and reducing the development of pathogenic micro-organisms in the intestine. Three animal feed samples were analyzed in this study. The organic acids were extracted from animal feed with water and then determined using two ion chromatography (IC) methods with suppressed conductivity detection. Method 1 is an anion exchange method using a Dionex IonPac AS11-HC-4µm column (Figure 1), which is ideal for separating a wide range of organic acids and inorganic anions simultaneously. Method 2 is an ion exclusion method using a Dionex IonPac ICE-AS6 column (Figure 2), which is ideal for measuring organic acids without interference from inorganic anions. Both methods were validated in terms of linearity, sensitivity, selectivity, accuracy, and precision. The limits of quantification (LOQs) ranged from 5.66 -13.4 mg/kg for method 1 and 9.49-26.2 mg/kg for method 2. While either method is appropriate for determining organic acids in animal feed, some feed contains malonic acid, which is better separated from citric acid using method 1. Additionally, some feed contains a large amount of sulfate, which is better separated from fumaric acid using method 2.

Determination of organic acids in animal feed using two ion chromatography methods

255th National Meeting (2018)

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