If detection is well known to offer high sensitivity and is regularly used for the detection "on capillary" of a CE system.In this poster we will describe three associations of three different separative techniques with laser-induced fluorescence (LIF) detector for the analysis of Amino Acids and catecholamines in microdialysates.In this application, the analysts have three main issues: he disposes of very few amount of sample, have to detect low concentration (for some compounds around 10-9M) and with enough speed to be able to run several samples per day.