Characterization of Near-Infrared Atomic Emission from a Radio-Frequency Plasma for Selective Detection in Capillary Gas Chromatography

Abstract

A radio-frequency plasma source has been characterized for use as an element-selective detector with capillary gas chromatography using atomic emission in the near-infrared region of the spectrum. With selected compounds introduced at rates similar to those encountered during a chromatographic run, the performance of the plasma has been characterized as a function of several interdependent variables, including plasma makeup gas flow, electrode spacing, and applied power. These settings have been optimized, and detection limits for several nonmetallic elements determined. Detection limits range from 0.2 to 50 pg/s.

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.…”

Chip-based ingroove microplasma with orthogonal signal collection: new approach for carbon-containing species detection through open air reaction for performance enhancement

“…Higher Ar flow rate can reduce the external disturbance to improve the stability of microplasma. But it decreases portability of this devices and inhibits molecular excitation by cooling the microplasma and discharge chamber, reducing the intensity of the excitation source, diluting the analytes and reducing the residence time of emitting species in the microplasma 31 32 33 . The flow rate was optimized by repeatedly injecting the same amount of hexane vapor into CIMP with varying the argon flow rate from 40 mL/min to 730 mL/min.…”

Microplasma-Based Detectors for Gas Chromatography: Current Status and Future Trends

“…Figure 1 shows a typical schematic configuration of the detector, which is a miniaturized version of the plasma developed by Skelton et al (42,43). In this detector, a 5-cm section of the stationary phase and polyimide coating was burned off at the end of a GC column, and the final 2 cm of this uncoated capillary with a protective silica tube served as the plasma tube.…”