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What is the difference between C18 and C8 columns?

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What is the difference between C18 and C8 columns?

C8 column refers to a type of column used in the reverse-phase chromatography, containing octylsilane as its stationary phase, while the C18 column refers to another type of column used in the reverse-phase chromatography, containing octadecylsilance as the stationary phase.

Are all C18 columns the same?

The different C18 columns are made to allow for different selectivities. Although all your columns are C18 functionalized phases, they will differ in hydrophobicity, peak shape (depending of degree and quality of end-capping and purity of silica) and selectivity and perhaps pore radius.

What are the differences between C4 C8 and C18 columns in HPLC?

C18 has 18 carbon atoms while C8 has only 8 carbon atoms. C18 has a longer carbon chain, but C8 has a shorter one. C18 has higher retention while C8 has shorter retention. C18 has higher hydrophobicity, but C8 has a lower hydrophobicity….Follow Pharmaguideline.

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What does C18 mean in HPLC column?

C18 is octyldecylsilane and contains 18 carbons bound to the silica. So they have more carbons and a longer carbon chain than C8 (8 carbons) or C4 (4 carbons). Because of the extra carbons, C18 has a larger surface area that the mobile phase has to travel across.

Is C18 polar or nonpolar?

A C18 column is an example of a “reverse phase” column. Reverse phase columns are often used with more polar solvents such as water, methanol or acetonitrile. The stationary phase is a nonpolar hydrocarbon, whereas the mobile phase is a polar liquid.

What is ODS and BDS column?

ODS and BDS are two columns used for reverse-phase chromatography. The key difference between ODS and BDS column is that ODS column contains free –OH functional groups, whereas BDS column contains deactivated –OH groups. Moreover, ODS columns have high peak tailing while BDS columns are designed to reduce peak tailing.

What is difference between ODS and C18 column?

The AQ type C18 column, such the ODS-B, has an end-capping that reduces phase collapse greatly, so it can be run in 100% water if needed. The ODS-A column has a more typical hydrophobic end-capping.

How do I select columns in HPLC?

These guidelines should help you make the right choice.

  1. Separation modes. Your first task in picking a column is selecting a separation chemistry.
  2. Column length. After you’ve decided on a column type, consider its length.
  3. Size and type of column particles.
  4. Throughput.

Is C18 column polar or nonpolar?

What are the detectors used in HPLC?

Lesson 6: Detectors for HPLC

  • UV, VIS, and PDA Detectors. Refractive-Index Detector.
  • UV, VIS, and PDA Detectors.
  • Refractive-Index Detector.
  • Evaporative Light Scattering Detector.
  • Multi-Angle Light Scattering Detector.
  • Mass Spectrometer.
  • Conductivity Detector.
  • Fluorescence Detector.

Is stationary phase polar?

Stationary phases are usually very polar, while mobile phases vary widely in polarity, but are less polar than the stationary phase. This is called normal phase (NP) chromatography.

What is phenyl column?

Phenyl columns are first reversed-phase columns, and give retention just as other reversed-phase columns. Next they give specific retention increments for analytes that interact via pi-pi interactions, or a lack of increment for analytes that do not have such specific interactions.

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