• Very selective to nitrogen and phosphorous
  • Detects levels to 10ppb
  • Exceptionally rugged NPD bead
  • Similar in design to an FID

The Nitrogen Phosphorus Detector (NPD) is similar in design to the FID, except that the hydrogen flow rate is reduced to about 3 ml/min and an electrically heated thermionic bead ( NPD bead ) is positioned near the jet orifice. Nitrogen or phosphorus containing molecules exiting the column collide with the hot bead and undergo a catalytic surface chemistry reaction. The ions created in this reaction are attracted to a collector electrode, amplified, and output to the data system.

The NPD is commonly used to detect pesticides, herbicides, and drugs of abuse because it responds to N-P compounds about 100,000 stronger than normal hydrocarbons, making it very selective. When combined with the chlorine/bromine selective DELCD, the combined detector is ideal for pesticide screening since the NPD selectively detects the organo-phosphate pesticides, while the DELCD detects only the chlorinated species. Together all pesticides can be detected, and the relative responses can help to identify pesticide species.

The SRI ceramic NPD bead is exceptionally rugged and long-lasting, offering service from 100-1000 hours depending on operating conditions.


Up to six detectors can be mounted on the 8610C GC Mainframe.



Fourteen detector combinations are available for mounting on the SRI Models 8610C and 310 GC mainframes.You can also upgrade your current GC or add more analytical power to your lab with these detectors as Stand-Alone units on the Model 110 detector chassis.

Up to six detectors may be mounted along the right hand side of the 8610C GC's column oven and used simultaneously (although some rare combinations of detectors may conflict because of space limitations). Each detector is equipped with a thermostatted heater block for temperature stability, electronic pressure controlled (EPC) support gases, such as hydrogen and air for the FID, and internal amplifier electronics. Select your detector type(s) based on your particular measurement application, detection limit required, matrix interferences, and/or regulatory guidelines.

All detectors require factory installation.

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