We are developing plasma cells integrated into micro-fluidic devices for Lab-on-Chip applications in cooperation with CASECT Ltd. and R.I.C.. These are to be applied as sensitive detectors for gas chromatographs and similar analytical equipment. In Helium plasmas at atmospheric or slightly reduced pressures a sensitivity to gaseous hydrocarbons below 1 ppm by volume has been achieved. The readout of the plasma is performed spectroscopically by measuring the intensity of the CH A→X Band and the C2 Swan Bands. The combination of the micro-plasma with a miniature spectrometer gives a highly compact detector system.

It has been shown, that the usual scaling laws for d.c. glow discharges hold at least approximately up to atmospheric pressure. The visual appearance of the discharge obtained is a real glow discharge.

References:

[1] Jan C. T. Eijkel, Herbert Störi and Andreas Manz, A Molecular Emission Detector on a Chip Employing a Direct Current Microplasma Anal. Chem. 1999, 71, 2600-2606

[2] Jan C. T. Eijkel, Herbert Störi and Andreas Manz, An atmospheric pressure dc glow discharge on a microchip and its application as a molecular emission detector J. Anal. At. Spectrom., 2000, 15, 297-300

[3] Jan C. T. Eijkel, Herbert Störi and Andreas Manz, A dc Microplasma on a Chip Employed as an Optical Emission Detector for Gas Chromatography Anal. Chem. 2000, 72, 2547-2552