2.4 - Application of a New Non-Radioactive Field Emission based Electron Source in Electron Capture Detectors

14. Dresdner Sensor-Symposium 2019
2019-12-02 - 2019-12-04
2. Innovative Messsysteme
C. Wendt, E. Bunert, S. Zimmermann - Leibniz University Hannover, Hannover/D, M. Bachmann, F. Düsberg, S. Edler, C. Langer - KETEK GmbH, München/D, R. Lawrowski, M. Hausladen, R. Schreiner - OTH Regensburg, Regensburg/D
40 - 43


Since the introduction of the Electron Capture Detector (ECD) by Lovelock and Lipsky more than 60 years ago, ECDs have become one of the most sensitive and thus most important detectors in gas chromatography for the detection of electron affine substances like halogens and chlorofluorocarbons [1]. Such compounds can be found in many hazardous chemicals such as pesticides. Although sensitivity and linearity of ECDs have been improved over time the principal of operation is still the same [2–4].
Free electrons generated by a radioactive electron source, such as 63 Ni, are captured by electron affine analyte molecules reducing the number of free electrons, which otherwise reach the detector electrode inside the ECD [1]. This current reduction is the primary detector signal, which is related to the concentration of analytes in the sample [1–4]. The radioactive electron source is easy to employ and does not need any external power supply or maintenance. However, legal restrictions apply on sale, usage, and disposal of radioactive sources, which increase the total cost of ownership by a significant amount. Hence, a strong demand exists to replace radioactive electron sources in ECDs. Therefore, the research and development of non-radioactive electron
sources for ECDs is an ongoing task for many years. However, just two solutions among several other attempts stood up. One approach is to generate free electrons through a pulsed helium discharge [3]. ...