Differbetween
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.
- What is the meaning of ODS column?
- What is difference between ODS and BDS column?
- Which column is more polar c8 or C18?
- Is C18 column polar or nonpolar?
- Why pH is important in HPLC?
- Why C18 column is used in HPLC?
- What is RRT in HPLC?
- What is the tailing factor?
- Why phosphate buffer is used in HPLC?
- What is polar and nonpolar?
- Which column is used in HPLC?
- What is pore size in HPLC column?
What is the meaning of ODS column?
An ODS column is filled with a packing of octadecylsilyl groups (ODS groups or C18 groups) chemically bonded to a silica gel carrier. ODS columns are used for reverse-phase chromatography. ODS columns find a wide range of applications due to their high theoretical plate number and rapid equilibration.
What is difference between 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.
Which column is more polar c8 or C18?
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.
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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.
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.
Why C18 column is used in HPLC?
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 RRT in HPLC?
Relative retention time (RRT) is the ratio of the retention time of analyte peak relative to that of another used as a reference obtained under identical conditions.
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 phosphate buffer is used in HPLC?
Since the retention of ionizable compounds is very sensitive to the mobile phase pH, it is necessary to control the pH of the mobile phase by the addition of a buffer. Phosphate and acetate are particularly useful buffers because they can be used at wavelengths below 220 nm. ...
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 pore size in HPLC column?
The pore size of HPLC particles can vary widely from product to product, but should be consistent within a particular product line of columns. There are two general categories of pore sizes. Small-pore particles have pores ranging from about 6-15 nm (60-150 Å), with the majority in the 8-12-nm range.
