Atomic emission detector
The atomic emission detector (also AED for short) is an element-specific detector for gas chromatography .
Technology history
The first atomic emission detector for gas chromatography was introduced in 1989 by Hewlett-Packard (now Agilent Technologies ). In May 2002 this technology was licensed to Joint Analytical Systems GmbH, which has been producing and technically developing the AED since then.
Working principle
The atomic emission detector uses a (helium) plasma to atomize the analytes and stimulate them to emit light.
Energy is introduced through microwave radiation to create an ionized gas. Temperatures of several thousand Kelvin are reached, so that organic compounds completely break down into their atoms. At the same time, the high temperatures ensure that the atoms can reach an excited state. During relaxation, the absorbed energy is emitted in the form of electromagnetic radiation with clearly defined spectral lines that are element-specific. The intensity of the emitted light is directly proportional to the concentration of the element. Since the analytes elute separately from the GC column into the plasma, the result is element-selective chromatograms whose peak areas can be used for quantification.
Modern devices work with a photodiode array (PDA) in order to be able to specifically record several elements simultaneously. The examined spectral range extends from approx. 170 nm to 840 nm. The detection limit depends on the elements to be analyzed and the matrix and sometimes reaches ranges of 0.2 picograms / second.
Related devices
Individual evidence
- ^ Daniel C. Harris: Textbook of Quantitative Analysis . Springer Spectrum, Berlin / Heidelberg 2014, ISBN 978-3-642-37788-4 , p. 662 .