Elution

<h2 id="eluotropic-series">Eluotropic series</h2>
<p>An eluotropic series is  listing of various compounds in order of eluting power for a given <a href="/facts/Adsorbent/ARH9peYM">adsorbent</a>. The "eluting power" of a <a href="/facts/Solvent/LoMPMz8S">solvent</a> is largely a measure of how well the solvent can "pull" an <a href="/facts/Analyte/qWzKoY8L">analyte</a> off the adsorbent to which it is attached. This often happens when the eluent adsorbs onto the stationary phase, displacing the analyte. Such series are useful for determining necessary solvents needed for <a href="/facts/Chromatography/2FrvPjNV">chromatography</a> of chemical compounds. Normally such a series progresses from non-polar solvents, such as <a href="/facts/N-hexane/JxPecNPt">n-hexane</a>, to polar solvents such as <a href="/facts/Ethanol/3lCLfBSP">ethanol</a>, <a href="/facts/Methanol/EIfpoNCg">methanol</a> or <a href="/facts/Water/0lkXnJPK">water</a>. The order of solvents in an eluotropic series depends both on the <a href="/facts/Stationary_phase_(chemistry)/2FrvPjNV">stationary phase</a> as well as on the compound used to determine the order.
</p>
<table><tbody><tr><th colspan="9">Adsorption strength (least strongly adsorbed → most strongly adsorbed)</th></tr><tr><td>Saturated hydrocarbons; alkyl halides</td><td>Unsaturated hydrocarbons; alkenyl halides</td><td>Aromatic hydrocarbons; aryl halides</td><td>Polyhalogenated hydrocarbons</td><td>Ethers</td><td>Esters</td><td>Aldehydes and ketones</td><td>Alcohols</td><td>Acids and bases (amines)</td></tr></tbody></table>
<table><tbody><tr><th colspan="13">Eluting power (least eluting power → greatest eluting power)</th></tr><tr><td>Hexane or pentane</td><td>Cyclohexane</td><td>Benzene</td><td>Dichloromethane</td><td>Chloroform</td><td>Ether (anhydrous)</td><td>Ethyl acetate (anhydrous)</td><td>Acetone (anhydrous)</td><td>Methanol</td><td>Ethanol</td><td>Pyridine</td><td>Acetic acid</td><td>Water</td></tr></tbody></table>
<h2 id="eluent">Eluent</h2>
<p>The eluent or eluant is the "carrier" portion of the mobile phase. It moves the analytes through the <a href="/facts/Chromatography/2FrvPjNV">chromatograph</a>. In <a href="/facts/Liquid_chromatography/2FrvPjNV">liquid chromatography</a>, the eluent is the liquid solvent; in <a href="/facts/Gas_chromatography/kwLY8vt1">gas chromatography</a>, it is the carrier gas.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a>
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<h2 id="eluate">Eluate</h2>
<p>The eluate contains the <a href="/facts/Analyte/qWzKoY8L">analyte</a> material that emerges from the <a href="/facts/Chromatography/2FrvPjNV">chromatograph</a>. It specifically includes both the analytes and coeluting solutes passing through the column, while the eluent is only the carrier.
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<h2 id="elution-time-and-elution-volume">Elution time and elution volume</h2>
<p>The "elution time" of a solute is the time between the start of the separation (the time at which the solute enters the column) and the time at which the solute elutes.  In the same way, the elution volume is the volume of eluent required to cause elution.  Under standard conditions for a known mix of solutes in a certain technique, the elution volume may be enough information to identify solutes.  For instance, a mixture of <a href="/facts/Amino_acid/WDxYwBny">amino acids</a> may be separated by <a href="/facts/Ion-exchange_chromatography/L1HFf4rA">ion-exchange chromatography</a>.  Under a particular set of conditions, the amino acids will elute in the same order and at the same elution volume.
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<h2 id="antibody-elution">Antibody elution</h2>
<p><a href="/facts/Antibody_elution/54YvHKEb">Antibody elution</a> is the process of removing antibodies that are attached to their targets, such as the surface of <a href="/facts/Red_blood_cell/Kggpq8Jh">red blood cells</a>. Techniques include using heat, a freeze-thaw cycle, ultrasound, acids or organic solvents. No single method is best in all situations.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Chromatography/2FrvPjNV">Chromatography</a></li>
<li><a href="/facts/Desorption/rWdeJjxn">Desorption</a></li>
<li><a href="/facts/Electroelution/hb6vxW2Q">Electroelution</a></li>
<li><a href="/facts/Gradient_elution/UNT9jPp0">Gradient elution</a> in high performance liquid chromatography</li>
<li><a href="/facts/Leaching_(chemistry)/hQ5JQhpF">Leaching</a></li></ul>

<ul><li>Brown, Phillis (2001). <i>Advances in chromatography</i>. <a href="/facts/CRC_Press/duTuH4hz">CRC Press</a>. p. 36. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-8247-0509-2.</li></ul>
<h2 id="external-links">External links</h2>
<ul><li><a href="https://web.archive.org/web/20090602132046/http://www.lcsupport.com/glossary.htm">Chemistry glossary</a></li>
<li><a href="http://www.stenutz.eu/chem/solv1.html">Eluotropic series</a> <a href="https://web.archive.org/web/20151222084322/http://www.stenutz.eu/chem/solv1.html">Archived</a> 2015-12-22 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"IUPAC Gold Book: eluent". International Union of Pure and Applied Chemistry. doi:10.1351/goldbook.E02040. Retrieved 2008-09-28. {{cite journal}}: Cite journal requires |journal= (help) <a href="http://goldbook.iupac.org/E02040.html" target="_blank">http://goldbook.iupac.org/E02040.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>George H. Roberts (2006). "Elution Techniques in Blood Bank" (PDF). American Medical Technologists (AMT). Archived from the original (PDF) on 2019-07-11. Retrieved 2020-07-22. <a href="https://web.archive.org/web/20190711220035/http://www.americanmedtech.org/files/STEP_Online_articles/301.pdf" target="_blank">https://web.archive.org/web/20190711220035/http://www.americanmedtech.org/files/STEP_Online_articles/301.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
</ol>

Elution open-in-new

Elution