Optimization of Discharge Parameters for a Flat-Type Radio-Frequency Glow Discharge Source Coupled to a Quadrupole Mass Spectrometer System

Abstract

A radio-frequency (rf)-powered glow discharge (GD) atomization/ionization source for nominally flat sample types (>6 mm o.d.) has been designed and coupled to a commercial GD mass spectrometer system, the VG GloQuad. This source was evaluated and optimized for conducting as well as nonconducting samples. A parametric study has been conducted on this rf-GDMS system with respect to discharge power, Ar flow (cell pressure), limiting orifice plate (anode) diameter, and ion sampling distance. Analytical characteristics under the optimized source parameters—including stabilization times (5 min for conducting samples, 60 min for nonconducting samples); repeatability (overall internal <2% RSD, overall external <8% RSD employing ion beam ratios); quantification; and detection limits—were evaluated for both conducting and nonconducting samples.