Eur. Phys. J. D (2012) 66: 161
https://doi.org/10.1140/epjd/e2012-20709-1

Regular Article

Diagnostics of atmospheric pressure microplasma with a liquid electrode

Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, 338-8570 Saitama, Japan

^a e-mail: chenq02lzu@gmail.com
^b Present address: Department of Bioengineering, The University of Tokyo, 113-8656 Tokyo, Japan.

Received: 7 December 2011
Received in final form: 29 February 2012
Published online: 29 June 2012

Abstract

A rf atmospheric pressure microplasma (APMP) in contact with a liquid electrode is characterized by an optical emission spectroscopy (OES) and a liquid chromatography. The results show that the solution conductivity is the essence for determining the APMP properties rather than the solution pH value. A liquid acidification observed during the APMP treatment is ascribed to the salvation of nitrogen related species created by the APMP. In addition, a typical two-sheath structure of the APMP is revealed by the spatial distribution of OES along the plasma volume. The estimated electron density of the APMP is as high as 10¹⁴–10¹⁵ cm^-3.