difference between c18 and phenyl column

1. What is difference between ODS and C18 column?
2. Is C18 column polar or nonpolar?
3. What does C18 column mean?
4. What is ODS and BDS column?
5. What is the tailing factor?
6. Why pH is important in HPLC?
7. What is polar and nonpolar?
8. Which column is used in HPLC?
9. What is a column in HPLC?
10. What is normal phase column?
11. What is pore size in column?
12. What is polar column?

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. ... Compounds that require more than 50% organic to elute will be less affected by the hydrophilic end-capping on the ODS-B.

Is C18 column 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 does C18 column mean?

C18 columns are HPLC (high performance liquid chromatography) columns that use a C18 substance as the stationary phase. ... C18 simply means that the molecules contain 18 carbon atoms, so the other atoms in the molecule can vary, leading to significantly different substances.

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 the tailing factor?

The tailing factor is a measure of peak tailing. It is defined as the distance from the front slope of the peak to the back slope divided by twice the distance from the center line of the peak to the front slope, with all measurements made at 5% of the maximum peak height.

Why pH is important in HPLC?

When samples contain ionisable compounds, mobile phase pH can be one of the most important variables in the control of retention in a reversed‑phase HPLC (RP-HPLC) separation. ... Since most compounds analysed by RP-HPLC contain one or more acidic or basic functional groups, most mobile phases require pH control.

What is polar and nonpolar?

Nonpolar bonds form between two atoms that share their electrons equally. Polar bonds form when two bonded atoms share electrons unequally.

Which column is used in HPLC?

The reversed-phase HPLC column is the most versatile and commonly used column type and can be used for a wide range of different types of analytes. Normal-phase HPLC columns have polar packing. The mobile phase is nonpolar and therefore usually an organic solvent such as hexane or methylene chloride.

What is a column in HPLC?

Columns are the main component in HPLC because the column is responsible for the separation of the sample components. The sample passes through the column with the mobile phase and separates in its components when it comes out from the column. ... The material filled in the HPLC columns is known as a stationary phase.

What is normal phase column?

When chromatographic separation is done in a normal phase mode, the surface chemistry of the stationary phase has a polar characteristic. The mobile phase is generally nonpolar organic solvent (such as hexane or heptane).

What is pore size in column?

The surface area of the particle is inversely proportional to the pore diameter; therefore, a 3 mm particle with a 120 nm pore diameter will have more than twice the surface area of a 3µm particle with a 300 nm pore diameter. There are a number of pore diameters used by manufacturers to control retention.

What is polar column?

Polar. ... These columns are commonly used to separate polar analytes (such as alcohols, amines, carboxylic acids, diols, esters, ethers, ketones, and thiols) that contain 1) primarily carbon and hydrogen atoms, and 2) also some bromine, chlorine, fluorine, nitrogen, oxygen, phosphorus, and/or sulfur atoms.