Electron Capture Detector | GC-ECD

The Electron Capture Detector (ECD) in gas chromatography (GC) is employed to detect compounds capable of undergoing electron capture reactions, displaying heightened sensitivity towards electronegative elements like halogens, as well as select nitrogen and oxygen compounds.

Figure 1. Electron Capture Detector (ECD)

Within the ECD, a radioactive source, Nickel-63, emits beta particles serving as a source of free electrons. The sample, comprising the compounds under analysis, is introduced into the chromatogram and traverses the electron capture chamber, propelled by a carrier gas such as Nitrogen or Argon. Electronegative compounds within the sample, including halogenated hydrocarbons or specific nitrogen and oxygen compounds, engage in electron capture, forming negative ions.

The electron capture process results in a reduction of electrical conductivity within the chamber, subsequently leading to increased current flow. The change in current is amplified, generating a signal that is then detected and recorded by the data system. The signal’s magnitude correlates directly with the concentration of electronegative compounds in the sample. Operating with a continuous emission of beta particles from a radioactive source, the ECD sustains a constant background signal. To rectify this background and enable precise analyte detection, a reference channel devoid of sample injection is incorporated.

The ECD exhibits high selectivity for electronegative compounds, rendering it particularly effective in detecting halogenated substances like chlorinated and brominated compounds. Widely utilized in environmental analysis, pesticide residue analysis, and identification of specific pharmaceutical and industrial compounds, the Electron Capture Detector’s specialization in electronegative compound detection makes it an indispensable tool in analytical chemistry.

Users of this detector are required by regulations of the Nuclear Regulatory Commission (NRC) to be familiar with radiation safety procedures.

The Electron Capture Detector (ECD) cell, which contains the radioactive ionisation source, is fixed within the detector tower and cannot be removed. Do not attempt to remove the cell from the tower. Regulations for the handling of radioactive materials strictly prohibit unlicensed disassembly. Evidence of removal voids the warranty. Violations of these regulations are reported to the NRC. In such cases, it is possible that you could come in contact with radioactive material when checking or adjusting the carrier gas flow rate. Always wash your hands after handling the top of the ECD.

Consumables and Spare Parts

Spares:

The ECD is not user serviceable, contact your local SCION sales representative to arrange a visit from a  SCION service engineer

Consumables:

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