Determination of Underivatized Amines by Capillary Electrophoresis and Capillary Electrochromatography

Summary Electroseparation methods are perfectly applicable for the analysis of relatively polar compounds such as underivatized amines. These systems provide a series of advantages over the commonly employed chromatographic methods such as the more straightforward possibility of miniaturization and integration and low cost of analysis. If the analysis of amines is performed without a precedent derivatization step additional benefits like the avoidance of all types of pitfalls related to this procedure can be achieved. Unfortunately the analysis of amines in their underivatized form also generates some new problems such as the necessity to separate compounds with often quite similar structures and the need to find detection systems providing sufficient sensitivity for these compounds. The capillary electroseparation method most commonly employed for underivatized amines still is capillary zone electrophoresis and up to now a substantial number of reports exist, describing the application of this technique for a variety of amines in different of matrices ranging from biological fluids to environmental samples. Detection is mostly performed using spectrophotometric detectors (mainly because of their presence in most commercially available instruments) in particular UV-vis detectors either in the indirect mode for simple amines or in the direct mode for heterocyclic or aromatic amines. Some work describing the use of electrochemical detection (mostly conductivity detection) also exists. Optimum choice for the detection of underivatized amines, especially due to their easy ptonizability, is the use of a mass spectrometric detector. This can also be seen from the increasing number of publications dealing with this issue.