Scientific Equipment Source
4-555 Wentworth Street East
Oshawa, ON, L1H 3V8
Canada
Tel: 905-231-0930
Fax: 905-231-0944

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HP 5890 Detector boards

TCD Board

FID Board

ECD Board

NPD Board

There are many detectors which can be used in gas chromatography. Different detectors will give different types of selectivity. A non-selective detector responds to all compounds except the carrier gas, a selective detector responds to a range of compounds with a common physical or chemical property and a specific detector responds to a single chemical compound. Detectors can also be grouped into concentration dependant detectors and mass flow dependant detectors. The signal from a concentration dependant detector is related to the concentration of solute in the detector, and does not usually destroy the sample Dilution of with make-up gas will lower the detectors response. Mass flow dependant detectors usually destroy the sample, and the signal is related to the rate at which solute molecules enter the detector. The response of a mass flow dependant detector is unaffected by make-up gas. 

A number of detectors are used in gas chromatography. The most common are the flame ionization detector (FID) and the thermal conductivity detector (TCD). Both are sensitive to a wide range of components, and both work over a wide range of concentrations. While TCDs are essentially universal and can be used to detect any component other than the carrier gas (as long as their thermal conductivities are different than that of the carrier gas, at detector temperature), FIDs are sensitive primarily to hydrocarbons, and are more sensitive to them than TCD. Both detectors are also quite robust. Since TCD is non-destructive, it can be operated in-series before an FID (destructive), thus providing complementary detection of the same eluents.

Some gas chromatographs are connected to a mass spectrometer which acts as the detector. The combination is known as GC-MS.

Detector Type Support gases Selectivity Detectability Dynamic range
Flame ionization (FID) Mass flow Hydrogen and air Most organic cpds. 100 pg 107
Thermal conductivity (TCD) Concentration Reference Universal 1 ng 107
Electron capture (ECD) Concentration Make-up Halides, nitrates, nitriles, peroxides, anhydrides, organometallics 50 fg 105
 Nitrogen-phosphorus (NPD) Mass flow Hydrogen and air Nitrogen, phosphorus 10 pg 106
Flame photometric (FPD) Mass flow Hydrogen and air possibly oxygen Sulphur, phosphorus, tin, boron, arsenic, germanium, selenium, chromium 100 pg 103
Photo-ionization (PID) Concentration Make-up Aliphatics, aromatics, ketones, esters, aldehydes, amines, heterocyclics, organosulphurs, some organometallics 2 pg 107
Hall electrolytic conductivity (ElCD) Mass flow Hydrogen, oxygen Halide, nitrogen, nitrosamine, sulphur    

 

If you are a bargain hunter please give us a call, we always have instruments in stock, which have not been refurbished and can be sold as is in working condition.

Scientific Equipment Source provides service and training on site in most of central Ontario this includes neighboring cities Ajax, Whitby, Pickering, Oshawa, Toronto, Mississauga. We can also provide training and courses on site on chromatograph (GC), HPLC in the Durham region; this includes Pickering, Ajax, Whitby, Oshawa. For other customers we can be also flexible on arrangements. For the rest of customer any equipment for repair has to be sent back by a courier.