Nitrogen–phosphorus_detector

Nitrogen–phosphorus detector

Nitrogen–phosphorus detector

Add article description

The nitrogen–phosphorus detector (NPD) is also known as thermionic specific detector (TSD) is a detector commonly used with gas chromatography, in which thermal energy is used to ionize an analyte.[1][2] It is a type of flame thermionic detector (FTD), the other being the alkali flame-ionization detector (AFID also known as AFD).

With this method, nitrogen and phosphorus can be selectively detected with a sensitivity that is 104 times greater than that for carbon.[citation needed]

NP-Mode

A concentration of hydrogen gas is used such that it is just below the minimum required for ignition. A rubidium or cesium bead, which is mounted over the nozzle, ignites the hydrogen (by acting catalytically), and forms a cold plasma. Excitation of the alkali metal results in ejection of electrons, which in turn are detected as a current flow between an anode and cathode in the chamber. As nitrogen or phosphorus analytes exit the column, they cause a reduction in the work function of the metal bead, resulting in an increase in current. Since the alkali metal bead is consumed over time, it must be replaced regularly .

See also

  1. [1]
    Wolfgang Kleiböhmer (2001). Environmental Analysis. Elsevier. pp. 8–. ISBN 978-0-444-50021-2.
  2. [2]
    Burgett, Charles A.; Smith, Douglas H.; Bente, H.Bryan (1977). "The nitrogen-phosphorus detector and its applications in gas chromatography". Journal of Chromatography A. 134 (1): 57–64. doi:10.1016/S0021-9673(00)82569-8. ISSN 0021-9673.


Stub icon

This article related to chromatography is a stub. You can help Wikipedia by expanding it.
Share this article:

This article uses material from the Wikipedia article Nitrogen–phosphorus_detector, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.