Talk:Size-exclusion chromatography

Wiki Education Foundation-supported course assignment

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Arahman6777.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 09:26, 17 January 2022 (UTC)

Permeation and filtration?

The gel filtration chromatography page lists gel permeation chromatography as a different method. Are not gel permeation, gel filtration, gel exclusion, size exclusion, and molecular sieve all the same thing? Srnec 20:48, 14 March 2006 (UTC)

Yes, yes, yes, no, and no.

Gel permeation, filtration, exclusion are are the same. Size exclusion is a bit more general, since it doesn't require the stationary phase to be a gel. Molecular sieves can be completely different. Usually these are used in a non-chromatographic mode, and involve a certain amount of affinity (for example, using molecular sieves to dry an organic solvent).

--Takometer 04:29, 26 March 2006 (UTC)

Gel filtration chromatography refers to the Size exclusion chromatography separation of water soluble ligands in aqueous mobile phase. Gel permeation chromatography refers to the Size exclusion chromatography separation of organic soluble ligands in aqueous mobile phase.

Article cleanup

Technical jargon was a bit overused in the article, I've cut out everything that couldn't be explained or re-wrote it. The gel filtration article now redirects here and I've merged the information. I have also removed the example, as it was overly confusing and better explained by the existing article on gel filtration. A copy of the example is left here for discussion purposes:

Let's say we have two types of particle we would like to separate, a large and a small particle. Our beads (which completey exclude the large particle) occupy 80% of the unit volume, and 50% of the beads (40% of the total volume overall) are a channel accessible to just the small particle. 25% of the beads (20% overall) are inaccessible to the small particle but accessible to solvent, and 25% is solid. Our column contains 100mL of total volume (beads + solvent), and we flow liquid through the column at .8 mL/min.

Note that the total volume accessible to solvent is 80 mL, so it will take 100 minutes for the solvent to flow through. The small particles can access 60 mL of space, and they will elute in 75 minutes. The big particles can only see 20 mL of space, and will elute from the column in 25 minutes. Since the big particles are completely excluded from the beads, their elution volume (20mL) is known as the void volume, and the solvent volume is known as the column volume.

I feel this point is worthy of inclusion, but I don't feel confident enough in simplifying it:

Unlike ion-exchange chromatography or affinity chromatography, SEC relies entirely on diffusion, so samples necessarily undergo a dilution, and resolution is adversely affected by increasing the injection volume. Slower solvent speeds will improve resolution to a certain point, but eventually nonspecific diffusion overtakes as a confounding factor.

I would appreciate if someone could simplify this statement and include it -- Serephine / talk - 12:07, 29 April 2006 (UTC)

References?

there are no references?? Really? --128.227.51.30 00:13, 2 July 2007 (UTC)

Advantages section misnamed?

Hi all, I think that the advantages section is slightly misnamed as it also deals with a couple of disadvantages. I would re-write it myself but I'm supposed to be revising! Overall its a really easy to read, good article though, thanks! --Noosentaal^·talk· 14:43, 16 May 2009 (UTC)

Concentration vs. Elution volume

Hello,
In many papers I see a figure of conc. vs. volume, which is created based on a gel-exclusion chromatography.
Could you please help me understand these figures, and how get from a specific data point in such a figure to explicit particle volume?
For example, say that for a concentration of y the elution volume is x. What is this particle radius (assuming that it is a perfect sphere)?
Thank you! Omer http://sites.google.com/site/omermar/
—Preceding unsigned comment added by Omermar (talk • contribs) 12:13, 4 January 2010 (UTC)

Merge Absolute size exclusion chromatography

Related stub would be a good section in this article. --Kkmurray (talk) 16:01, 22 April 2010 (UTC)

I agree. LightScatteringGuy (talk) 17:48, 27 April 2010 (UTC)

Merged --Kkmurray (talk) 19:29, 27 April 2010 (UTC)

General citation refurbishing

Inspired by the "unclear citation style" template I made a general citation remake.
All of the citations made using the old <ref></ref> method were changed into their apropriate Wiki citation script templates. This way it is easier to maintain a consistent citation style in a long run. All of the citation scipts follow rules mentioned below.
Journal articles:

• Names and surnames should be in separate fields and the names shortened to only first letters without any dots or spaces between. If number of authors is greater than 4, a "displayauthors=3" should be used. Using the "vauthors" to put all the authors in one go is good too, but you have to make the apropriate "et. al." yourself as the "displayauthors" ignors this field.
  
• Journal names should be added in their ISO 4 abbreviated form if you can find their resepective Wiki page: [[journal wiki page|ISO 4 abbr.]]. The ISO 4 abbr. are placed in the infobox of a respectie journal Wiki page. This way we can get a shorter citation for journals with long names and the full name is still going to show as a tooltip on mouseover and anybody can easily get to the journal's page. This way it is neat and not confusing.
• All of the journal citations should at least have a DOI or PMID number added. Both are also good. For very old articles with no such numbers, an url to a page showing a way to get that article (i. e. library catalog record) would be very apreciated. For articles with both PMID and PMC numbers, the PMID is sufficient. Current version of citation script treats PMC as a link as well, thus "painting" all of the citation's title blue, which many times makes it almost entirely blue and less readable. That is why I prefer just PMID, but that is just me.
  

Books:

• Names and surnames should be in separate fields. If edithors are pressent, they should be placed in their respective "no. editor last name" and "no. editor first name" fields. If number of authors/editors is greater than 4, a "displayauthors=3" or "displayeditors=3" should be used. Using the "vauthors" or "veditors" to put all the authors/editors in one go is good too, but you have to make the apropriate "et. al." yourself as the "displayauthors" and "displayeditors=3" ignor this field.
• Name list format "vanc" namelistformat=vanc should be used. It is better to have full names in the code and just display them in vancouver style as we don't know if in the future other styles will be more preferable. Also, when you use automatic citation adding from ISBN it many times gives you names in separate fields and it is easier to just add "vanc".
• OCLC number in my opinion should be placed as frequent as the ISBN number. The page you get from klicking the ISBN link is a bit overwhelming for a new user who usually wants to get straight to the book's page. This, or Library of Congress reference number, would be a good addition to book citations.
  
• Simmilar to the issue with journal names, if it is possible to wikilink the books' publisher, please do so. It is preffered to add the Publisher's short name if it exists.
  
• Instead of making several references for different page citations of a same book, it is advised to use the "rp" template, after the citation, instead. This way it is easier to keep a tidy reference list.
  

Websites:

• No specyfic instructions here other than having a proper title (if not visible on the page itself, look for the tab title in your browser or in the metadata of the webpage), webpage name and acces date. Authors and creation / last update date are also apreciated.
  

Other documents:

• Can be referenced using the "website" citation script. The type of the document can be specyfied by the "type" field.
  

Dates:

• I really want to advertise the dd MM yyyy (i. e. 1 Jan 2019) format as it at the same time looks plesant and does not require much space as the default mm-dd-yy format. Aside from that, I don't think it is necessary to add more than a year for both journal and book citations.
  

If anybody would like to propose some changes, please write. As of now, the citations are in a uniform style. Therefore I removed the "unclear citation style" template from the article.
--Light Code (talk) 13:37, 3 January 2019 (UTC)