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

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A radio frequency plasma detector for capillary GC has been modified for oxygen‐selective detection. Purification of the plasma gas and purging of both ends of the discharge region with helium were crucial to minimizing oxygen background emission from impurities in the plasma. With a pure helium plasma, eluting hydrocarbons released oxygen from the discharge region resulting in interfering signals on the oxygen channel. These interfering signals were efficiently reduced by using a methane‐doped (0. 15%) low power RF plasma (15 W) sustained in a high make‐up flow (150 mL/min). With this plasma, a 103:1 oxygen‐to‐carbon selectivity and a 100 pg oxygen/s detection limit were obtained. The detector was linear over three orders of magnitude. The detection system has been used to screen for oxygenated compounds in two environmental samples.

OriginalsprogEngelsk
TidsskriftJournal of High Resolution Chromatography
Vol/bind15
Udgave nummer10
Sider (fra-til)677-681
Antal sider5
ISSN0935-6304
DOI
StatusUdgivet - okt. 1992

ID: 231657077