Detection of dissolved metals using a liquid electrode dielectric barrier discharge

Analysis of dissolved metals in liquid samples using a dielectric barrier discharge with flowing liquid electrode has been studied. Inside a fused-silica capillary the discharge is ignited between the liquid surface and a tungsten electrode, driven by a pulsed high voltage. In this manner the flowing liquid acts as second electrode itself and the wall of the capillary as dielectric barrier. Due to a pulsation of the electrode gap the discharge is sustainable for one hour and more. Calibration measurements are performed for several alkali, alkaline earth metals and silver. With a flow rate of 20 µL min-1 detection limits between 0.02 mg L-1 for potassium and 6.9 mg L-1 for barium are determined. Application as metal detection system for environmental liquid samples as well as monitoring device in flow systems seems possible.