N,N-dimethylglycine is an amino acid derivative found in plants and animals. The respective sodium salt is available as nutritional supplement. In this context it is expected to have athletic performance enhancer effects and acts against fatigue. It is also accepted as a poultry feed addition. The determination is performed applying a Dose-in Gradient with subsequent conductivity detection after sequential suppression. To enhance the selectivity of the separation, a combination of a Metrosep A Supp 7 - 250/4.0 and a Metrosep A Supp 16 Guard/4.0 was used.