PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Gas Chromatography1. Introduction2. Stationary phases3. Retention in Gas-Liquid Chromatography4. Capillary gas-chromatography5. Sample preparation and injection6. Detectors(Chapter 2 and 3 in The essence of chromatography)A. Types of Columns in GC1. Packed-bed column (d > 2 mm, packing particle from 100 to 250 micron) 2. Micro-packed column (d < 1 mm, dp/dc less than 0.3) 3. Packed capillary column (d < 0.6 mm, packing particle 5-20 micron) 5. Support coated open tubular (SCOT) Liquid phase + glass powder or particle support 6. Porous layer open tubular column (PLOT) Particle support 4. Wall coated open tubular columns (WCOT)Thin layer of stationary phase coated directly on the wall of the tube.Question. In a WCOT GC, two component, each with plate height H = 0.0064 cm, are observed have a resolution of 0.5 when the length of column is 1 m. How long should the column to be achieve baseline resolution? Gas-liquid Chromatography: Classical packed column, and WCOTGas-Solid Chromatography: Classical packed column, and PLOTPartition mechanism Adsorption mechanismB. Stationary phase in Gas-liquid Chromatography 1. General Considerations for liquid stationary phase materials:a. un-reactive with carrier gas and solutesb. low vapor pressurec. good coating characteristics (i.e. wet the materials used in the column fabrication) d. Have reasonable solubility in some common volatile organic solvent.e. Wide temperature operating range. The low limit: melting point, or glass point for polymers The maximum temperature is determined by thermal stability and vapor pressure. In practice, the higher T is that can be maintained without breakup of the liquid film into droplets.2. Types of liquid stationary phasesa. Hydrocarbon and Perfluorocarbon stationary phases (non-polar) Squalane (C30H62); Apiezon; Apolane-87 (C87H167) b. Ether and ester stationary phasesPoly-ethers (e.g., poly-phenyl ethers), phthalate esters c. Liquid organic-salts stationary phasesAlkylammonium or alkylphosphonium with nucleophilic anions (such as BF4-)d. poly(siloxane) stationary phasesState of the art GC performancelog k = c + rR2 + sπ2 + aΣα2 + b Σ β2 + llogLHHH16(Gas chromatography)System constants (c, m, r, s, a, b, and l): depended on chromatographic system conditions: mobile phase, stationary phase, and temperature. Solute descriptors (R2, π2, Σ α2, Σ β2, logL, and Vx): depended on solute properties163. How to choose liquid stationary phases.Kamlet-Taft parametersSystemsSolutesSystem constants (c, m, r, s, a, b, and l): depended on chromatographic system conditions: mobile phase, stationary phase, and temperature. Effects on system constantslog k = c + rR2 + sπ2 + aΣα2 + b Σ β2 + llogLHHH16(Gas chromatography)System constants (c, m, r, s, a, b, and l): depended on chromatographic system conditions: mobile phase, stationary phase, and temperature. Temperature Effectslog k = c + rR2 + sπ2 + aΣα2 + b Σ β2 + llogLHHH16(Gas chromatography)C. Solid stationary phases in Gas-solid chromatography G-S chromatography has a narrow range applications Such as separation of volatile hydrocarbons and halocarbons solvents, sulfur gases. Advantages: high stability. Disadvantages: low capacity factor, irreversible-adsorption.State of the art performanceQuestion. In a WCOT GC, two component, each with plate height H = 0.0064 cm, are observed have a resolution of 0.5 when the length of column is 1 m. How long should the column to be achieve baseline resolution? 5. A graduate student performed a separation of a potential drug A and B in extraction of natural products. A mixture of component A and B were separated on a 30-cm long uniform LC column. The retention times of these two components were 16.40 and 18.63 min, and the base-widths were 1.11 and 1.21 min, respectively. A component that does not be retained by the stationary needs 1.30 min to pass the column. Please calculate (1) the resolution, plate number and plate height of these two components. (2) How long should the column be to achieve a baseline resolution of these two peaks? and what are the retention times for components A and B in this new