Determination of organic compounds by gas chromatography using a new capacitively coupled microplasma detector

The microplasma is implemented as an on-column optical emission detector. The arrangement consists of two cylindrical electrodes placed side by side on the fused silica separation capillary of 250 mum id and an optical fibre for coupling emitted light to a spectrometer. The plasma is generated with an ac voltage of 20 kV and 20 kHz by capacitive coupling of the energy into the capillary and can be sustained at flow rates employed in gas chromatography at atmospheric pressure. The detection of volatile organic compounds was possible via the emission from atomic carbon at 247.9 nm and from CN at 385.2 nm. Benzene, was determined with a detection limit of approximately 80 pg of carbon.