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Capillary Columns

Capillary Columns. Nicholas H. Snow Department of Chemistry, Seton Hall University, 400 South Orange Avenue, South Orange, NJ 07079 snownich@shu.edu. Capillary/Open Tubular Column. WCOT - Wall Coated Open Tubular. Capillary Column Dimensions. Other Types of Capillary Columns.

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Capillary Columns

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  1. Capillary Columns Nicholas H. Snow Department of Chemistry, Seton Hall University, 400 South Orange Avenue, South Orange, NJ 07079 snownich@shu.edu

  2. Capillary/Open Tubular Column

  3. WCOT - Wall Coated Open Tubular

  4. Capillary Column Dimensions

  5. Other Types of Capillary Columns

  6. Tubing Material • Stainless Steel • reactive • Glass • can be made inert • difficult to handle • Fused Silica • flexible • most inert • most popular

  7. Fused Silica Surface • Contains 0.1% -OH groups • Very inert • Uniform chemical surface

  8. Fused Silica • High tensile strength • Flexible • Sheath of polyimide • Very inert

  9. Capillary vs. Packed

  10. Packed Column - ECD

  11. Capillary Column - ECD

  12. Important Column Parameters

  13. Column Diameter

  14. Column Length

  15. Column Length Recommendations

  16. Stationary Phase Film Thickness • Starting point: 0.25mm • Compromise: resolution and capacity • Practical operating temperatures • Speed or resolution

  17. Thick Film Stationary Phase • Advantages • increased retention for volatiles • increased capacity • Disadvantages • less efficient • higher temperatures • higher bleed

  18. Natural Gas

  19. Thin Film Stationary Phase • Advantages • high efficiency • lower elution temperatures • fast analysis • Disadvantages • low capacity • limited trace analysis

  20. Thin Film SeparationAir Freshener

  21. Stationary Phase Requirements • Selectivity • Low Bleed Rate • Reproducibility

  22. Common Stationary Phasespolysiloxane gum phases

  23. Stationary Phasespolyglycol

  24. Crosslinked Stationary Phases • More stable • Clean by rinsing • Longer lifetimes

  25. Carrier Gas Flow Rate

  26. Review - Capillary Columns

  27. Review - Capillary Columns

  28. Column Selection

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