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Gas Chromatography (GC) with Flame Ionization Detector (FID) and Hot Wire Detector (HWD)

The materials characterization laboratory is equipped with a Varian CP-3800 gas chromatograph (GC) with a Flame Ionization Detector (FID) (Figure 1). It has Electronic Flow Control (EFC) and a PoraPLOT Q column installed, which is used for low molecular weight, volatile organic compound separations. A Varian CP-8410 autosample delivery system is also available. The Varian Star Chromatography Workstation Version 5.51 software is operating with Ethernet communications with full networking capability.

Figure 1: Varian CP-3800 gas chromatograph (GC) with a Flame Ionization Detector (FID).

The gas chromatograph utilizes principles of molecular interaction to achieve separation of complex mixtures. A long (10 - >100m), coiled column is contained within the gas chromatograph and the sample to be analyzed is separated based on the different interactions between the sample components and the “stationary phase” of the column. After separation, samples are carried into a detector. The hot wire detector (HWD) is capable of operating up to 400°C. This detector is relatively insensitive as compared to FID but responds to all solutes that differ in heat capacity and thermal conductivity from those of the carrier gas.

Data from the GC can be used qualitatively for identification based on elution time from the column and quantitatively as the FID signal is proportional to the mass of carbon present in a sample.

At CAMMP, the GC is used to determine gas concentrations while producing carbon nanotubes and concentration of organic compounds during catalytic testing and whole-cell biosensor testing.