[Determination of metal by liquid electrode discharge atomic emission spectrometry with a new design]

A liquid electrode discharge atomic emission spectrometry has been developed with a new design. Plasma fluctuation from the variations in the gap between the W anode and liquid cathode was eliminated by providing a sawtooth-shaped drainage structure. The sawtooth was placed at a distance of 2 mm from the glass capillary top. When a solution is pumped through a glass capillary, the liquid drop forms and rises and on reaching the maximum size collapses while the next drop forms. This results in a continuous change in the interelectrode distance which will cause the discharge current to change, plasma flickers and is extinguished. With the new design, the surface tension of the drop was destroyed before its growing up, and the solution was flowing along the drainage groove. The discharge can last for 3 hours at least with such arrangement. The analytical response curves for lead, chromium, cadmium, zinc, vanadium, nickel, copper, silver and cobalt demonstrated good linearity. The limit of detections of lead, chromium, cadmium, zinc, vanadium nickel, copper, silver and cobalt were determined to be 0.08, 0.61, 0.48, 1.60, 10.88, 0.48, 0.084, 0.048 and 0.27 mg x L(-1) respectively.