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Ion-exchange chromatography (or ion chromatography) is a process that allows the separation of ions and polar molecules based on the charge properties of the molecules. It can be used for almost any kind of charged molecule including large proteins, small nucleotides and amino acids, with the experimental solution to be separated collectively known as the analyte. It is often used as a first step in protein purification. An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow robert ford An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ...
A commonly-used example of a polar compound is water (H2O). ...
A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
A nucleotide is an organic molecule consisting of a heterocyclic nucleobase (a purine or a pyrimidine), a pentose sugar (deoxyribose in DNA or ribose in RNA), and a phosphate or polyphosphate group. ...
Phenylalanine is one of the standard amino acids. ...
Image File history File links Download high-resolution version (853x404, 31 KB) I, the creator of this work, hereby release it into the public domain. ...
Image File history File links Download high-resolution version (853x404, 31 KB) I, the creator of this work, hereby release it into the public domain. ...
History Ion-exchange methods have been in use since 1850, when H. Thompson and J. T. Way, researchers in England, treated various clays with ammonium sulfate or carbonate in solution to extract the ammonia and release calcium. In 1927, the first zeolite mineral column was used to remove interfering calcium and magnesium ions from solution to determine the sulfate content of water. The modern version of IEC was developed during the wartime Manhattan Project. A technique was required to separate and concentrate the radioactive elements needed to make the atom bomb. Researchers chose adsorbents that would latch onto charged transuranium elements, which could then be differentially eluted. Ultimately, once declassified, these techniques would use new IE resins to develop the systems that are often used today for specific purification of biologicals and inorganics. In the early 1970s, ion chromatography was developed by Hamish Small and co-workers at Dow Chemical Company as a novel method of IEC usable in automated analysis. IC uses weaker ionic resins for its stationary phase and an additional neutralizing stripper, or suppressor, column to remove background eluent ions. It is a powerful technique for determining low concentrations of ions and is especially useful in environmental and water quality studies, among other applications.
The Dow Chemical Company technology was acquired by Durrum Instrument Corp. (maker of the Durrum_D-500), which later formed a separate business unit for its new IC products, naming it Dionex (Dow Ion Exchange). Dionex Corporation was incorporated in Sunnyvale, California in 1980, and, led by A. Blaine Bowman, purchased the Dionex assets. The Dow Chemical Company (NYSE: DOW) is a multinational corporation headquartered in Midland, Michigan, USA. In terms of market capitalization, it is the second-largest chemical company in the world, smaller than only DuPont. ...
Durrum D-500 Amino-acid Analyzer The D-500 Amino Acid Analyzer was designed and built by Durrum Instruments in the late 1960s. ...
Principle Ion exchange chromatography retains analyte molecules based on coulombic (ionic) interactions. The stationary phase surface displays ionic functional groups that interact with analyte ions of opposite charge. This type of chromatography is further subdivided into cation exchange chromatography and anion exchange chromatography: Coulombs torsion balance In physics, Coulombs law is an inverse-square law indicating the magnitude and direction of electrostatic force that one stationary, electrically charged object of small dimensions (ideally, a point source) exerts on another. ...
- Cation exchange chromatography retains positively charged cations because the stationary phase displays a negatively charged functional group such as a phosphoric acid
- Anion exchange chromatography retains negatively charged anions using positively charged functional group such as a quaternary ammonium cation
A cation is an ion with positive charge. ...
Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is an inorganic mineral acid having the chemical formula H3PO4. ...
Categories: Chemistry stubs ...
Separating Proteins Proteins have numerous functional groups that can have both positive and negative charges. Ion exchange chromatography separates proteins according to their net charge, which is dependent on the composition of the mobile phase. By adjusting the pH or the ionic concentration of the mobile phase, various protein molecules can be separated. For example, if a protein has a net positive charge at pH 7, then it will bind to a column of negatively-charged beads, whereas a negatively charged protein would not. By changing the pH so that the net charge on the protein is negative, it too will be eluted.
Elution by changing the ionic strength of the mobile phase is a more subtle effect - it works as ion from the mobile phase will interact with the immobilized ion in preference over those on the stationary phase. This "shields" the stationary phase from the protein, (and vice versa) and allows the protein to elute.
Typical Technique
 Ion Chromatography Workstation A sample is introduced, either manually or with an autosampler, into a sample loop of known volume. A buffered aqueous solution known as the mobile phase carries the sample from the loop onto a column that contains some form of stationary phase material. This is typically a resin or gel matrix consisting of agarose or cellulose beads with covalently bonded charged functional groups. The target analytes (anions or cations) are retained on the stationary phase but can be eluted by increasing the concentration of a similarly charged species that will displace the analyte ions from the stationary phase. For example, in cation exchange chromatography, the positively charged analyte could be displaced by the addition of positively charged sodium ions. The analytes of interest must then be detected by some means, typically by conductivity or UV/Visible light absorbance. Image File history File linksMetadata Download high-resolution version (2304x1728, 1293 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Ion exchange chromatography Metadata This file contains additional information, probably added from the digital camera or scanner used...
Image File history File linksMetadata Download high-resolution version (2304x1728, 1293 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Ion exchange chromatography Metadata This file contains additional information, probably added from the digital camera or scanner used...
Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acid-base extraction Acids: Strong acids Weak acids Superacids Lewis acids Mineral acids Organic acids Bases: Strong bases Weak bases Superbases Lewis bases Organic bases edit Buffer solutions are solutions which resist change...
An agarose is a polysaccharide polymer material, generally extracted from seaweed. ...
Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ...
Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. ...
In order to control an IC system, a Chromatography Data System (CDS) is usually needed. In addition to IC systems, some of these CDSs can also control Gas Chromatography (GC) and HPLC systems.
Manufacturers of Ion Chromatographs
Manufacturers of Ion Chromatography Accessories and Columns Phenomenex, Inc. ...
See also The isoelectric point (pI) is the pH at which a molecule or surface carries no net electrical charge. ...
A HPLC. From left to right: A pumping device generating a gradient of two different solvents, a steel enforced column and an apparatus for measuring the absorbance. ...
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