Isotachophoresis in free-flow using a miniaturized device.

For the first time, we report a miniaturized approach for isotachophoresis employing the technique of free-flow electrophoresis. Using a micromachined separation chamber with a volume of 200 nL, a sample mixture of fluorescein, eosin G, and acetylsalicylic acid was separated, stacked, and concentrated in less than a minute. Additionally, an isotachophoretic separation of a reaction mixture of myoglobin and fluoresceinisothiocyanate as a fluorescence label has shown the potential of this method for on-line sample preparation.