Multi‐element selective radio frequency plasma detector for capillary gas chromatography

Abstract

A radio frequency plasma detector for element specific detection in gas chromatography is described. The detector is comprised of a radio frequency (300 kHz) discharge between electrodes in helium, and utilizes a low‐resolution emission spectrometer to monitor selected spectral emission lines produced when the helium discharge decomposes and excites the atomic constituents in the chromatographic column effluent. The spectrometer is tuned to an atomic emission line in the near‐infrared portion of the spectrum, and the emission intensity from the discharge region of a selected line is used to monitor the concentration of the element producing that line. Acceptable detector sensitivity was achieved by the use of a high‐throughput optical system. Selectivity was achieved by a combination of correct line selection, plasma and carrier gas purification, and plasma gas doping.

Sample Analysis with Miniaturized Plasmas

“…In 1988 Skelton et al developed a 350 kHz radio frequency plasma (RFP) that was used for sulfur selective gas chromatographic analysis by GC/OES. [34][35][36] This detector was found to have low limits of detection of sulfur (0.5 pg/s) and a good linear response (4 decades). The detector consists of a helium radio frequency plasma sustained inside of a 1 mm quartz tube.…”

Evaluation of a radio frequency plasma for oxygen‐selective detection in capillary gas chromatography

“…The optical region of the RPD was similar to the arrangement used by Skelton et a1 [7][8][9] The plasma was generated between the top electrode and the detector base by means of an HPG-2 radio frequency power supply (350 kHz; EN1 Power Systems, Rochester, USA). Spectral emission viewed side-on through the discharge tube was transmitted through a pair of achromatic lenses (f = 58 mm, 12 7 mm diameter; Newport, Fountain Valley, USA) and a 595 nm cut-off filter (Melles Griot, Irvine, USA) into a Model H-20 monochromator (0.5 mm slits, Instruments SA, Metuchen, USA).…”

Analytical Detectors Based on Microplasma Spectrometry

“…In 1988, Skelton et al developed a 350 kHz radio frequency plasma which was used for sulfur selective gas chromatographic analysis by GC/OES [21][22][23]. This detector was found to have low limits of detection of sulfur (0.5 pg/s) and a good linear response (four decades).…”