ENVIRONMENTAL APPLICATIONS OF THE PULSED-DISCHARGE ELECTRON-CAPTURE DETECTOR

A new type of electron-capture detector is introduced that does not require a radioactive source for the generation of electrons. Because a pulsed, high-voltage discharge is used instead, we have named this detector the pulsed-discharge electron-capture detector (PDECD). Preliminary results are given that demonstrate its viability as a detector for monitoring electron-capturing species in the environment. Especially impressive are the results obtained in the detection of chlorofluorocarbons (CFCs), which play an important role in the destruction of the ozone layer. Initial data obtained at a detector temperature of 100°C (with N2 as dopant) for CHCI3, CCI4, CCI2=CCI2, CH2CI2, CFCI3, and CF2CI2resulted in minimum detectable quantities of 110 fg, 8 fg, 32 fg, 59 pg, 2 fg, and 83 fg, respectively. Similar MDQ values have been obtained using 0.2% H2as dopant. Electron-capture coefficients for these compounds are comparable with previous literature data from a radioactive ECD. Eight pesticides have been analyzed using the PDECD, and the resulting chromatogram gives symmetrical peaks. The minimum detectability for lindane was 250fg. The analytical importance of this detector is significant, and future work is being directed toward the use of this detector for field studies. © 1992 Journal of Chromatographic Science.