The use of capillary zone electrophoresis to determine lactate, pyruvate and other organic acids in neonatal urine

Summary

The determination of the organic acids oxalic, malonic, maleic, succinic, pyruvic, lactic, 3-hydroxybutyric and hippuric was investigated using capillary zone electrophoresis. They were separated in a fused-silica capillary (70 cm×75 μm id) which was filled with 50 mM sodium tetraborate (pH 10) containing a cationic surfactant as the electroosmotic flow modifier and Ca²⁺ in the buffer to aid separation of closely migrating peaks and improve peak shape. The developed method was successfully applied to the determination of organic acids in urine. The effect of passing samples through a C-18 solid phase extraction cartridge was investigated briefly, to try to simplify the sample prior to injection. Finally the developed screening procedure was used to study a set of urine samples some of which were obtained from children with metabolic errors resulting in the excretion of an abnormal organic acid profile. Discrimination between normal and abnormal samples was achieved. The results were in good agreement with information obtained by a GC-MS study of the same urine samples.