Dear Harshad,
The type of stationary Phase of HPLC columns can be predict by prefixes and suffixes.
There are some examples:
-Sil, Si, Silica -spher, -sorb are indicate the silica gel or silica based columns.
-spher indicates spherical material
-Sorb used for irregular material (exception is Spherisorb this is spherical in nature)
-WP means wide pore e.g 300A pore size
NPB, NPR, NPS used for Non Porous Beads, Non Porous Resin, Non Porous Silica
ODS, RP-18 indicates C-18 columns
and so on.
I recommend you to read Book written by Stavros Kromidas " Practical Problem Solving in HPLC" published by Wiley-VCH.
Distinction between the column is based on reverse phase and normal phase columns.
Different companies gives their own brandnames and sale.
Reverse phase-C-18 or ODS=Octa Decyl Silane, C-8
Normal phase-Amino, diol etc.
Gas Chromatographic Columns
In gas chromatography the mobile phase is a gas. Gas chromatographic columns are usually between 1 and 100 meters long.
Gas liquid chromatography(GLC): The liquid stationary phase is bonded or adsorbed onto the surface of an open tubular (capillary) column, or onto a packed solid support inside the column.
Gas solid chromatography (GSC): The stationary phase is a solid and the analyte absorbs onto the solid. GSC uses a packed or open capillary column. GSC is used for analytes that do not absorb onto a liquid stationary phase. GSC is a popular method for analyzing carbon disulfide, hydrogen sulfide, carbon monoxide, carbon dioxide, nitrogen oxide, volatile hydrocarbons, halo-carbons, solvents, and other gases found in the air. The solid stationary phase is usually made of graphite carbon blocks, alumina, silica, molecular sieves, or porous polymers beads. Molecular sieves are composed of aluminum and silicate ion exchangers. Porous polymer beads are made up of styrene cross-linked by divinylbenzene.
Open Tubular (capillary) Columns:
When the stationary phase is uniformly distributed on the interior surface of column it is called an open tubular (capillary) column. Open tubular columns are longer, smaller in diameter, and more efficient than packed columns. Open tubular columns have less flow resistance which allows for them to be longer and have a lot of theoretical plates. Capillary columns are between 3 and 100 meters long and form a helical shape. The most common stationary phases used for open tubular columns are polysiloxanes. Polysiloxanes are silicon atoms which have attached oxygen and R groups. The R groups can vary, which makes polysiloxanes very versatile . There are three types of open tubular columns: wall-coated (WCOT), support-coated (SCOT), and porous-layer (PLOT). WCOT is the most popular type of open tubular column. The wall coated open tubular column consists of a capillary tube with its interior surface coated in a tiny layer of stationary phase. The most common type of wall coated open tubular column used is fused-silica, because it is stronger, inert, reliable, easy to use, and flexible. Fused silica capillary tubes are made from purified silica that has a small quantity of metal oxides dispersed throughout the silica. The fused silica column also has a layer of polyimide on the outside of the column, which makes the column flexible and extends the life of the column. Wall-coated open tubular columns can also be made out of plastic, glass, stainless steel, aluminum, or copper. A support-coated open tubular column has a thin layer (approximately 30 µm) of liquid support matter. This type of open tubular column has a greater amount of stationary phase than the wall coated column, so it can handle a larger quantity of sample.
A porous-layer open tubular (PLOT) column is very similar to a support-coated open tubular column. The only difference between the two types of columns is that a PLOT does not have a liquid stationary phase. PLOT columns are used for gas solid chromatography. PLOT columns have a solid layer of carbon, molecular sieves, cyclodextrins, inorganic oxides, or porous polymers, coating the inner wall of the column. PLOT columns can be up to 100 meters long. The inner diameter of a PLOT column is between 0.25 and 0.53 mm. The stationary phase coating is between 5 and 50 micrometers thick.
Packed Columns (also applies to liquid chromatographic columns):
A packed column is dense and evenly packed by solid support. The solid support usually has a liquid stationary phase bonded to it. The solid support allows for the liquid stationary phase to be exposed to the maximum amount of the mobile phase. The solid support and stationary phase must be inert at high temperatures and allow for the mobile phase to be evenly distributed as it moves through the column. The packed columns are shorter in length and wider in diameter than the open tubular columns. The diameter of a packed column is usually between 2 and 4 mm. Packed columns are typically 1 to 5 meters long and also form a helical shape.The packing particles typically have a diameter of 100 to 250 micrometers. Micro-packed columns are packed capillary tubes and are packed with the same material as larger packed columns. The most common stationary phase used for packed columns is diatomaceous earth (diatomite). Diatomite is made up of diatom (single-celled algae) skeletons. The skeletons are composed of mostly silica, and small quantities of alumina and metallic oxides. Other popular stationary phases are pure silica (SiO2) and alumina (Al2O3). Alumina is great for separating aromatic hydrocarbons.
High Performance Liquid Chromatographic Columns:
High performance liquid chromatography (HPLC) is aslo known as liquid chromatography. HPLC uses a liquid moblie phase. The same basic principals from gas chromatography are applied to liquid chromatography. There are three basic types of liquid chromatographic columns: liquid-liquid, liquid-solid, and ion-exchange. Liquid-liquid chromatographic columns have the liquid stationary phase bonded or absorbed to the surface of the column, or packed material. liquid-liquid chromatographic columns are not as popular because they have limited stability and they are inconvenient. Partitioning occurs between the two different liquids of the mobile and stationary phases. In liquid-solid chromatographic columns the stationary phase is a solid and the analyte absorbs onto the stationary phase which separates the components of the mixture. In ion-exchange chromatographic columns the stationary phase is an ion-exchange resin and partitioning occurs with ion exchanges that occur between the analyte and stationary phase.
Usually HPLC has a guard column ahead of the analytical column to protect and extend the life of the analytical column. The guard column removes particulate matter, contaminants, and molecules that bind irreversibly to the column. The guard column has a stationary phase similar to the analytical column.
The most common HPLC columns are made from stainless steel, but they can be also made out of thick glass, polymers such as polyetherethelketone, a combination of stainless steel and glass, or a combination of stainless steel and polymers. Typical HPLC analytical columns are between 3 and 25 cm long and have a diameter of 1 to 5 mm. The columns are usually straight unlike GC columns. Particles that pack the columns have a typical diameter between 3 to 5 µm. Liquid chromatographic columns will increase in efficiency when the diameter of the packed particles inside the column decreases.
Ion Exchange Chromatographic Columns:
Ion exchange columns are used to separate ions and molecules that can be easily ionized. Separation of the ions depends on the ion's affinity for the stationary phase, which creates an ion exchange system. The electrostatic interactions between the analytes, moble phase, and the stationary phase, contribute to the separation of ions in the sample. Only positively or negatively charged complexes can interact with their respective cation or anion exchangers. Common packing materials for ion exchange columns are amines, sulfonic acid, diatomaceous earth, styrene-divinylbenzene, and cross-linked polystyrene resins. Some of the first ion exchangers used were inorganic and made from aluminosilicates (zeolites). Although aluminosilicates are not widely used as ion exchange resins used.
Size Exclusion Chromatographic Columns:
Size Exclusion Chromatographic columns separates molecules based upon their size, not molecular weight. A common packing material for these columns is molecular sieves. Zeolites are a common molecular sieve that is used. The molecular sieves have pores that small molecules can go into, but large molecules cannot. This allows the larger molecules to pass through the column faster than the smaller ones. Other packing materials for size exclusion chromatographic columns are polysaccharides and other polymers, and silica. The pore size for size exclusion separations varies between 4 and 200 nm.
References:
Skoog, D., Holler, J., Crouch, S. Principles of Instrumental Analysis, 6th Ed.; Thomson Brooks/Cole: Belmont, 2007.
Poole, C.F. The Essence of Chromatography; Elsevier: San Francisco, 2003.
Miller, J.J. Chromatography: Concepts and Contrasts, 2nd Ed.; John Wiley & Sons, Inc.: Hoboken, NJ, 2005.
Dear Harshad,
The type of stationary Phase of HPLC columns can be predict by prefixes and suffixes.
There are some examples:
-Sil, Si, Silica -spher, -sorb are indicate the silica gel or silica based columns.
-spher indicates spherical material
-Sorb used for irregular material (exception is Spherisorb this is spherical in nature)
-WP means wide pore e.g 300A pore size
NPB, NPR, NPS used for Non Porous Beads, Non Porous Resin, Non Porous Silica
ODS, RP-18 indicates C-18 columns
and so on.
I recommend you to read Book written by Stavros Kromidas " Practical Problem Solving in HPLC" published by Wiley-VCH.
From your question it seems you want to differentiate the various columns available for work. Are you planning to have many types of columns so you want to have an insight into the differences they have or you are just confused with the names like you mentioned. Most of the columns are made from silica as others suggested and already explained a lot too.
Important thing is your plan. It depends on the analysis you have to do. According to the type of analysis, columns are available and you can choose based on your need. Specifications for all types are available on the web as well as with the suppliers also. So just decide your plan of work, what is your exact need and select from the available ones.. :).. Thats all......
Gud Luck
Actually all the above column are same but they are called by different abbreviation for C18 column (ODS, C18, ) which is having Reverse phase bonded support of octadecyl group.
if you really want to distinguish column then their are distinguished on the basis of following (only in ccase of RP-HPLC )
1. carbon load (low or high)
2. End-capped or non-end capped
3. base deactivated non base deactivated
4. polymeric or monomeric.
so, if want to use the colum for seperation it should have high carbon load , endcapped , base deactivated and polymeric.
Which are such columns having high carbon load, end capped, base deactivated and polymeric?
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