T. Frentiu, A.M. Rusu, S.D. Anghel, S. Negoescu, A. Popescu, A. Simon, E.A. Cordos, Radiofrequency capacitively coupled plasma torch with central tubular electrode and outer ring electrode, ACH-Models In Chemistry, 136/1-2 (1999) 119-129

Title: Radiofrequency capacitively coupled plasma torch with central tubular electrode and outer ring electrode

Abstract: In the capacitively coupled plasma torch with tip-ring geometry, a part of the sample remains in the mantle of the plasma, without any interaction with its hot core, where the dissipated power is at maximum. The authors designed a new Ar RF CCP torch with central tubular electrode and outer ring. This new torch uses a single Ar flow, which assures the introduction of the sample through the tubular electrode into the central channel of the plasma. The argon plasma is generated at 275 W and 27.12 MHz and has a good stability when the inner diameter of the tubular electrode is 3.5 mm. In this paper the structure of the torch and the optimisation of main working parameters are presented, as well as the detection limits for Mg, Li, Na and Ca from liquid sample, as compared with those obtained in the torch in tip-ring electrode geometry. The improved interaction between the pneumatically nebulized liquid sample and the plasma and the lower background signal assure limits of detection for Mg, Ca, Na and Li (6, 9, 4, 5 ng/ml) 1.5-8 times better than the tip-ring type RF CCP.

Keywords: Atomic-Emission-Spectrometry; Microwave Plasma; Atmospheric-Pressure; Analytical Performance

Author: E. Cordos