New Instrumentation: Gas Chromatography / Thermal Conductivity Detector / Flame Ionization Detector - Methanizer
RJLG is expanding its use of gas chromatography (GC) instrumentation by adding a gas chromatography / thermal conductivity detector / flame ionization detector - methanizer to our current capabilities. The Company envisions using this instrument for the analysis of gas product purity, gas piping purity, and natural gas/BTU. The GC also has the capability to test compressed air as well as measure ambient air quality, indoor air quality, and medical air purity.

This new instrument has several unique features that will add value to RJLG's analytical capabilities, including:

• Dual detectors in series (TCD, FID) for increased application versatility
• A 10-port gas sampling valve, sample loop, and two column combination, providing the capability to separate hydrogen, oxygen, nitrogen, methane, C2-C6 hydrocarbons, carbon monoxide, and carbon dioxide with a single injection
• A 10-Stream selection valve autosampler, allowing automated sampling and analysis of up to 10 gas samples at a time
• Optional direct on-column or gas sampling loop injection capabilities

The thermal conductivity detector (TCD) is the most universal detector available. The TCD detector measures the difference in thermal conductivity of the carrier gas flow and the sample gas. The TCD consists of electrically heated filaments in a temperature-controlled oven. When an analyte elutes and the thermal conductivity of the column effluent is reduced, the filament heats up and changes resistance. This resistance change is sensed by a Wheatstone Bridge circuit which produces a measurable voltage change, which is translated into an analog signal that is sent to the data system for analysis.

The flame ionization detector (FID) responds to any molecule with a carbon-hydrogen bond. In the FID, the carrier gas effluent from the GC column is combined with a hydrogen/air mix, and routed through a stainless steel jet. The hydrogen/air mix supports a diffusion flame at the jet's tip which ionizes the analyte molecules. An electrostatic field is generated by the difference in potential between the positively charged collector electrode and the grounded FID jet. A collector electrode attracts the negative ions to the electrometer amplifier, producing an analog signal which is sent to the data system for analysis. The Methanizer option enables the Flame Ionization Detector to detect low levels of CO and CO2. It is installed as the removable jet in a special FID detector assembly. The Methanizer jet delivers the column effluent mixed with hydrogen to the FID detector.

The GC/TCD/FID-methanizer utilizes one 10-port gas sampling valve and two analytical columns to perform the separation and analysis of hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, and C1-C6 hydrocarbons, all in a single injection. The non-destructive TCD measures compounds whose concentrations are at least 250 ppm. The FID measures the C1-C6 hydrocarbons, plus CO and CO2, which are converted to methane by the Methanizer in the FID jet.