Derivatization reactions for use with the electron-capture detector

The electron-capture detector is a structure-selective detector with a wide response range for organic compounds. It is predominantly used to determine halogen-containing compounds, nitroaromatic compounds, and compounds with conjugated systems connecting at least two weak electrophore groups. High sensitivity and selectivity make it a general choice for trace analysis. For compounds with reactive functional groups and weak electron capture properties, derivatization affords a facile method to facilitate their detection. Reagents and reaction conditions for the formation of derivatives with electron-capturing properties are described in this review. The common methods for introducing an electrophore into organic compounds with polar functional groups include silylation, acylation, alkylation, esterification, Schiff base reagents, addition of halogens, and cyclic derivatives formed with bifunctional compounds. These reactions include reagents for general use as well as functional group selective reagents. In addition to the selection of reagents, the effect of the detector operating parameters on its response and details of the electron-capture mechanism for common derivatives are discussed.