Electron capture detection

From Glossary of Meteorology

electron capture detection

(Abbreviated ECD.) A detector used in a gas chromatograph that operates by sensing a decrease in the number of free electrons in the detector cavity due to their capture by electrophilic compounds eluting from the column of the chromatograph.

The free electrons are produced by beta decay of a radioactive isotope (e.g., 63Ni, half-life 92 years) in the detector cavity.