A simplified model of the ECD

A simplified model of the ECD is presented, which is based on the assumption that only a change in the concentration of electron is generating a signal. The model allows to determine four different time constants related to: the collection of electrons (₁), the loss of electrons in the capture process by the impurity molecules (₂), the loss of sample molecules by electron capture (_n) and the removing rate of molecules from the detector volume by the carrier gas (_v). The values of these time constants have been estimated to be in the range of s for ₁, ms for ₂, a part of a second for _n and a few seconds for _v. The electron capture efficiency coefficient (p) and the detection coefficient (S_d) have been defined. These coefficients serve in the model for the coulometric calculation of the mass of analyzed compounds, if the detector works using the conditions described.