RGD - Reduction Gas Detector

  • Detects reducing gases, such as CO to 50 ppb level, and H2 to 0.5 ppm
  • Heated UV detection cell with absorbance output
  • User packable reaction tubes (requires mercuric oxide, not included)

The SRI reduction gas detector is sensitive to volatile reducing compounds down to the ppb level, and is often used to detect atmospheric carbon monoxide and hydrogen.

When compared to the FID detector, the RGD is ten times more sensitive to unsaturated hydrocarbons, and virtually unresponsive to saturated hydrocarbons. This combination of sensitivity and selectivity allows the analysis of atmospheric pollutants such as ethylene, benzene, carbonyl sulfide, phosphine, and methanol.

Our RGD uses a mercuric oxide reaction tube and a mercury lamp in a heated UV detector cell. When a reducing gas elutes from the column into the hot reaction tube, it reacts with the mercuric oxide to form mercury vapor. As it flows through the detector cell, the gaseous mercury absorbs the UV light from the mercury lamp inside the cell. The change in transmittance is converted by the data system into an absorbance output, which is proportional to the amount of reducing gas. A carbon filter at the UV detector cell outlet traps the condensed mercury vapor for safe disposal.

High concentrations of chlorinated and aromatic compounds can easily contaminate the mercuric oxide bed, resulting in the need for replacement. Reaction tubes are easily replaceable, and blank reaction tubes can be economically packed by the user.

This four minute chromatogram shows the RGD response to 0.1 mL of 100 ppm hydrogen.
This four minute chromatogram shows the RGD response to 0.5 mL of room air.

RGD detector
Blank reaction tube and sealing frits

RGD - Reduction Gas Detector