• Bandpass Filters for Sulfur or Phosphorus
  • Simultaneous Sulfur and Phosphorus Detection with the Dual FPD
  • Detects Sulfur Compounds to 200ppb, Phosphorus Compounds down to 10ppb
  • Simultaneous Hydrocarbon Speciation with the FPD/FID or Dual FPD/FID

The FPD detector is similar to the FID except that the detector body is completely light tight and a second flow of hydrogen purges the optical path between the photomultiplier tube ( PMT ) and the hydrogen-rich flame. A bandpass filter at 393nm. for sulfur or 525nm. for phosphorus mounts in front of the PMT so only the emissions from sulfur or phosphorus are detected while other wavelengths are rejected.

While not 100% selective, the FPD is 100,000 times more sensitive for S-P compounds than for hydrocarbons. Sulfur compounds such as H2S or SO2 can be detected down to about 200 ppb and phosphorus to 10ppb. The phosphorus response is linear, but the sulfur response is exponential ( twice the sulfur yields four times the peak area ).

The dual FPD detector is equipped with two PMTs which allow simultaneous detection of sulfur and phosphorus, and either the single or dual FPD can be equipped with an FID collector electrode and electrometer which will detect the hydrocarbon peaks at the same time as the PMTs are responding to the S-P compounds.

The FID response is not as sensitive as a pure FID because the hydrogen-rich flame required for optimum S-P detection is not optimum for best hydrocarbon response. Users can easily optimize S-P response versus hydrocarbons response by simply adjusting the hydrogen/air mixture using the included EPC gas controls.

Click here for printable FPD technical overview (.pdf).



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.


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

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