Leibniz Universität Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, Appelstr. 9A, 30167 Hannover, Germany.
Leibniz Universität Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, Appelstr. 9A, 30167 Hannover, Germany.
J Chromatogr A. 2019 Nov 22;1606:460384. doi: 10.1016/j.chroma.2019.460384. Epub 2019 Jul 26.
With detection limits in the low ppb-range, electron capture detectors (ECD) are the most sensitive GC-detectors available for electron affine compounds, such as pesticides or chlorofluorocarbons. The working principle is based on the generation of free electrons at atmospheric pressure, which are usually emitted from a radioactive Ni-63 source. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation and disposal. Recently, we introduced a novel ECD based on a non-radioactive electron source, achieving comparable detection limits, e.g. 1 ppb (6 ng/l) for 1,1,2-trichloroethane. However, the linear range was still below that of radioactive ECDs. In addition, the detector volume was too large to be used as a GC detector. We now present an improved version of this non-radioactive ECD with significantly increased linear range of 6.5∙10 for 1,1,2-trichloroethane by implementing pulsed operation using a newly developed, autonomous control electronics. In addition, the detector volume is reduced to 100 μl, leading to faster response times, less memory effects and thus less peak broadening. The improved ECD with non-radioactive electron source reaches similar analytical performance compared to commercially available radioactive ECDs and thus can be used as a possible replacement of radioactive ECDs.
电子俘获检测器（ECD）的检测限可达低 ppb 级，是对电子亲和化合物（如农药或氯氟碳化合物）最敏感的 GC 检测器。其工作原理基于在大气压下产生自由电子，这些电子通常由放射性镍-63 源发射。然而，放射性材料的使用导致在购买、操作和处置方面受到监管限制。最近，我们引入了一种基于非放射性电子源的新型 ECD，实现了可比的检测限，例如对于 1,1,2-三氯乙烷为 1 ppb（6ng/l）。然而，线性范围仍低于放射性 ECD。此外，由于检测器体积过大，无法用作 GC 检测器。我们现在展示了这种非放射性 ECD 的改进版本，通过使用新开发的自主控制电子设备实现脉冲操作，将 1,1,2-三氯乙烷的线性范围显著提高到 6.5×10，此外，检测器体积缩小到 100μl，从而实现更快的响应时间、更少的记忆效应，因此峰展宽更小。这种具有非放射性电子源的改进型 ECD 与市售放射性 ECD 具有相似的分析性能，因此可以作为放射性 ECD 的替代方案。
