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Multi-Dimensional Gas Chromatography State-of-the-Art

Multi-Dimensional Gas Chromatography State-of-the-Art. J.-M. D. Dimandja January 16, 2007. Chromatography in Context. GCxGC Instrumentation. Detector. Injector. Data Processor. Secondary Column. Primary Column. Modulator. What is Modulation?. Demodulator. Modulator. Transmission.

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Multi-Dimensional Gas Chromatography State-of-the-Art

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  1. Multi-Dimensional Gas Chromatography State-of-the-Art J.-M. D. Dimandja January 16, 2007

  2. Chromatography in Context

  3. GCxGC Instrumentation Detector Injector Data Processor Secondary Column Primary Column Modulator

  4. What is Modulation? Demodulator Modulator Transmission Desired Audio Signal Audio Signal AM FM Demodulator Modulator Desired Multi-dimensional Signal 1st Dimension GC Signal Transmission Through 2nd GC Dimension

  5. Role of the GCxGC Modulator • Amplitude Modulation • Frequency Modulation • Phase Modulation • The modulator plays a key role in the optimization of a GCxGC method

  6. Types of GCxGC Modulators • Thermal Modulators • Valve Modulators • Will be covered by Prof. Seeley

  7. Modulator Figures-of-Merit • Sampling efficiency • Temperature operating range • Technical sophistication • Ruggedness • Cost

  8. Evolution of Thermal Modulators • Resistors • Thermal scanners • Thermal jets

  9. Thermal Resistor Principle • Resistive heating • Rapid cooling due to low thermal mass of the resistive film

  10. Rearview Defogger

  11. Defogger Operation • Resistive paint heated • Defogging occurs

  12. Napa Defogger kit

  13. The Original Resistor (Liu/Phillips, 1988) Electrically Conductive Paint Stationary Phase

  14. Resistor Pros/Cons

  15. Improvements • Two-stage modulation (Liu, 1989) • Thicker stationary phase (Liu, 1990) • Dry-ice resistor (Venkatramani, 1991) • Stainless-steel, multi-stage resistor (Burger, 2003)

  16. Resistor Summary • Interfaced with HRMS (1994) and TOF MS (1996) • Academia (prototype development), Industry (Shell), government R&D (CDC) • Cheap and easy to assemble, but not commercially viable

  17. Thermal Scanning Principle Mechanically activated modulator that scans a given section of the column to produce the modulation. 1 2

  18. Dual-Oven Heat Shuttle (Xu, 1993) 1 2

  19. Single-Oven Heat Shuttle (Xu, 1994) 1 2

  20. Inside-Oven Cryo-Shuttle (Marriott, 1995) 1 2

  21. Inside-Oven Heat Shuttle -- Thermal Sweeper (Ledford/Phillips, 1997) 1 2

  22. Thermal Scanner Pros/Cons

  23. Thermal Scanner Summary • First “commercial” system (Sweeper, 1997) • Petroleum industry, government R&D (CDC, CGA) • Data processing issues (no software for automated visualization and/or quantitation)

  24. Jet Modulator Principle • Active cooling and heating stages • Thermal scanners only have one active stage (either heating or cooling, but not both)

  25. Single-Stage, Dual-Jet (Beens, 2001) Trapping phase

  26. Single-Stage, Dual-Jet Release phase

  27. Two-Stage, Quad-Jet Modulation (Ledford, 2001) TRAP

  28. Two-Stage, Quad-Jet Modulation FOCUS

  29. Two-Stage, Quad-Jet Modulation RELEASE

  30. Two-Stage, Dual-Jet Modulation (Ledford, 2002)

  31. Two-Stage, Dual-Jet Modulation

  32. Two-Stage, Dual-Jet Modulation

  33. Two-Stage, Dual-Jet Modulation

  34. Thermal Jets Pros/Cons

  35. Thermal Jet Summary • Curent commercially available state-of-the-art in GCxGC • Industry, academia, government • Achilles heel: consumables • Gaines/Frysinger solution • Harynuk/Gorecki solution

  36. Conclusions

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