Nitrogen-Phosphorus Detector (NPD)

The Nitrogen-Phosphorus Detector (NPD) is a specialized instrument employed in Gas Chromatography (GC) for the discriminative detection of compounds containing nitrogen and phosphorus. Its functioning revolves around the principle of chemiluminescence, where chemical reactions result in the emission of light.

Nitrogen-Phosphorus Detector (NPD)

Figure 1. Nitrogen-Phosphorus Detector (NPD)

The sample, housing nitrogen- and phosphorus-containing compounds, is introduced into the GC. Within a combustion chamber, the sample undergoes combustion in the presence of air or oxygen, generating nitrogen oxides (NOx) and phosphorus oxides (POx). Subsequently, in a reaction chamber, the nitrogen oxides and phosphorus oxides partake in a recombination reaction, releasing energy in the form of photons.

The emitted photons are directed towards a photomultiplier tube (PMT), a light-sensitive device that converts the photons into an electrical signal. This electrical signal undergoes amplification and subsequent detection, with the signal magnitude directly proportional to the concentration of nitrogen- or phosphorus-containing compounds in the sample. To ensure precise quantification of the analytes of interest, the NPD often incorporates a baseline correction system to account for any background signal.

The NPD boasts high selectivity for nitrogen and phosphorus, rendering it exceptionally effective in detecting compounds with these elements. Sensitivity extends to amines, nitro compounds, and organophosphorus compounds. Widely utilized in various applications, the Nitrogen-Phosphorus Detector proves invaluable in environmental analysis, pharmaceutical research, and the identification of nitrogen- and phosphorus-based pesticides, where the discerning detection of compounds containing these elements is paramount.

Consumables and Spare Parts

Spare parts:

  • NPD Bead Conditioned and Tested (390607401)
  • Insulator lower (2100003200)
  • Insulator upper (2100003100)
  • Tower seals, 25/pk (1500334701)
  • O-ring 487 ID (2740928202)
  • Flame Tip Assy 0.02 ID (200193800)



41312148 15% GRAPHITE/85% VESPEL FERRULE 1/16″ WITH 0.4MM HOLE PK/10
41312149 15% GRAPHITE/85% VESPEL FERRULE 1/16″ WITH 0.5MM HOLE PK/10
41312150 15% GRAPHITE/85% VESPEL FERRULE 1/16″ WITH 0.8MM HOLE PK/10
41312153 15% GRAPHITE/85% VESPEL FERRULE 1/16″ NO HOLE PK/10

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