1 / 56

Factors Affecting Resolution

Factors Affecting Resolution. k`= K / ß. Modulators. Thermal modulator. Cryogenic modulator. Oberflächenchemie. Cross section of a F used S ilica C olumn O pen T ubular. PHASEN. Choosing the Bonded Phase. PG = polar amide group. R = C 14 alkyl. R1 = isopropyl shielding.

siusan
Download Presentation

Factors Affecting Resolution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Factors Affecting Resolution k`= K / ß

  2. Modulators Thermal modulator Cryogenic modulator

  3. Oberflächenchemie

  4. Cross section of a Fused Silica Column Open Tubular

  5. PHASEN

  6. Choosing the Bonded Phase

  7. PG = polar amide group R = C14 alkyl R1 = isopropyl shielding Triple endcapping, shielding Diisopropyl side groups provide steric protection against low pH Polar amide groupembedded in a long alkyl chain reduces interactiions between basic analytes and silica support Choosing the Bonded Phase

  8. PACKUNG HPLC

  9. Particle Shape Effect on chromatography Spherical particles offer reduced back pressures and longer column life when using viscous mobile phases like 50:50 MeOH:H2O.

  10. Particle Size • Effect on chromatography • Smaller particles offer higher efficiency, but also cause higher backpressure. • Choose 3 µm particles for resolving complex, multi-component samples. Otherwise, choose 5 or 10µm packings.

  11. Surface Area • Effect on chromatography • High surface area generally provides greater retention, capacity and resolution for separating complex, multi-component samples. Low surface area packings generally equilibrate quickly, especially important in gradient analyses.

  12. Kieselgelträgermaterial Rx-SIL(Sol Typ) Zorbax Xerogel (Sil Typ) STRUKTUR: GLEICHMÄSSIGE PARTKEL “SCHWAMM-STRUKTUR,” POLYMERES NETZWERK 50 80A/180 HOCH GUT HOCH ENG 70 100A/300 MITTEL SCHLECHT NIEDER - HOCH BREIT POROSITÄT (%): PARTIKEL GRÖSSE/ OBERFLÄCHE (M2/G) MECHAN. STABILITÄT: HOHE pH-STABILITÄT: REINHEIT: PORENGRÖSSE, PARTIKELGRÖSSE VERTEILUNG

  13. Pore Size • Effect on chromatography • Larger pores allow larger solute molecules to be retained longer through maximum exposure to the surface area of the particles. Choose a pore size of 150Å or less for sample MW  2000. Choose a pore size of 300Å or greater for sample MW > 2000.

  14. Endcapping • Effect on chromatography • Endcapping reduces peak-tailing of polar solutes that interact excessively with the otherwise exposed, mostly acidic silanols. Non-endcapped packings provide a different selectivity than do endcapped packings, especially for such polar samples.

  15. Carbon Load • Effect on chromatography • Higher carbon loads generally offer greater resolution and longer run times. Low carbon loads shorten run times and many show a different selectivity

  16. Bonding Type Monomeric bonding offers increased mass transfer rates, higher column efficiency, and faster column equilibration. Polymeric bonding offers increased column stability, particularly when highly aqueous mobile phases are used. Polymeric bonding also enables the column to accept higher sample loading.

  17. Acidity

  18. Mechanisms

  19. Thomas Mann

  20. SPME

  21. MULTIKAPILLARE

  22. FFF

More Related