Development of an atmospheric pressure glow discharge detector for capillary column gas chromatography

The use of the change in the oscillation frequency of the current of a new atmospheric helium glow discharge for sensitive signal detection for gas ch romatography is studied. The effluent of a capillary column is directed int o the glow discharge cell perpendicular to the axis of the glow discharge t hat existed between a platinum anode and cathode. A stable discharge is obt ained when several hundred volts are applied between the 0.2-mm gap between the anode and cathode. The effects of the electrode gap, discharge voltage and gas flow rate on the baseline frequency and discharge current were inv estigated. The chromatogram shows that the discharge current and discharge gap have a strong influence on the detector response. The discharge current shows positive peaks; however, frequency peaks are positive or negative de pending on the discharge conditions. The response of the detector is in the femto-mole and pico-mole range for nonane and decane.