Analysis of Organic Acids in Physiological Fluids by High Performance Liquid Chromatography

Abstract

Most organic acids in physiological fluids are carboxylic acids or their glycine or glucuronide conjugates. Also included are hydroxyl compounds, such as phenols or cresols. By definition, compounds with a primary amino group, detectable by conventional amino acid analysers, are excluded. Organic acids are produced continuously in the body as intermediates in the metabolism of amino acids, carbohydrates and fats, and of drugs and food additives. They do not accumulate in the body, since they are rapidly converted to non-acidic end products or excreted as water soluble metabolites i n urine. However, if they are produced in excess, or if their metabolism is prevented by an inherited enzyme defect, concentrations increase in the tissues, blood and urine. Examples of excessive production are during fasting ketosis, in which acetoacetic and 3-hydroxybutyric acids and a range of dicarboxylic acids derived from breakdown of fatty acids accumulate, and lactic acidosis, secondary to hypoxia, when increases in lactic, pyruvic and 2-hydroxybutyric acids are common.