Configuration of an Agilent Technologies 8890 Gas Chromatograph with a thermal conductivity detector (TCD) for the analysis of natural gas per GPA Method 2261 and ASTM D1945.1-3 TCD-A identifies the following analytes: Analyte, CAS # LDL (ppm) Max. (vol%) Isobutane, 75-28-5 100 10 n-Butane, 106-97-8 100 10 Isopentane, 78-78-4 100 2 n-Pentane, 109-66-4 100 2 Carbon dioxide, 12-38-9 100 20 Ethane, 74-84-0 100 100 Propane, 74-98-6 400 100 Oxygen/argon composite 100 20 Nitrogen, 7727-37-9 100 100 Methane, 74-82-8 100 100 Initial C6+ composite backflush4 400 1 Includes the following installed hardware: • One 10-port gas sampling/backflush to detector valve, two 6-port series bypass valves, and three pneumatic actuators • Auxiliary isothermal oven • Necessary analytical columns • Necessary restrictors and fittings Also includes method development, test chromatograms, and documentation. Application Notes: 1. Performance warranted to GPA 2261 and ASTM D1945 specifications 2. System will be configured with helium carrier gas. 3. Typical analysis time is 40 minutes. If n hexane is to be quantified and not in the backflush, analysis time will be about 70 minutes. 4. Any gas chromatograph system will become reduced over time and will absorb oxygen at trace levels. In this case the customer will need to passivate the system with air injections prior to analysis to prevent absorption. 5. An initial backflush method is not recommended for samples containing C6+ hydrocarbon concentrations exceeding 25% due to the possibility of interference between the backflush peak and the next eluting peak. 6. This method does not include the analysis of hydrogen or helium. If this is required, let your Wasson representative know. 7. This quote does not include linearity testing per ASTM D1945. Please let your sales representative know if this needs to be added to the quote.
