Emission studies on a glow discharge in atmospheric pressure air using water as a cathode

Abstract

A stable discharge was produced in atmospheric air using water as a cathode. Spectral lines of elements dissolved in tap water could be observed. It is demonstrated that the appearance of these spectral lines is a consequence of cathode sputtering of water during the discharge. The intensity of the lines was found to depend strongly on the acidity of the water. This kind of discharge gives a possibility for continuous analysis of water and waste water solutions.

Sample Analysis with Miniaturized Plasmas

“…The sample solution is electrically connected to the negative electrode such that the overflowing liquid surface becomes the discharge cathode. 59 Emission spectroscopy of metal analytes in the electrolyte solution has been performed in air at atmospheric pressure using this technique and the authors suggest the cathodic sputtering as being the key mechanism of sample transport from the liquid to the gas phase. A relationship between pH and spectral line intensity was interpreted as being due to a reaction between hydroxonium ions and solvated electrons, leading to an increase in the secondary electron emission coefficient.…”

Spectrochemical Analysis by Using Discharge Devices with Solution Electrodes

“…13 This glow discharge between a metal electrode and a flowing solution became known as an electrolyte-cathode discharge (ELCAD).…”

Spectral detection of metal contaminants in water using an on-chip microglow discharge

“…Atomic transitions of metallic impurities are typically best detected from spectroscopic analysis of dc plasma emissions [9]. Work has also been done employing the water sample as a cathode, with a metallic anode for spectroscopic use [10], [11], and detecting water impurities through spectral information. An effort to implement this system in a MEMS device has been reported very recently [12].…”