Talk:Chromatography
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[edit] This page needs a lot of more details
This page needs a lot of more details, what the procedures for the columns are, and the pros and cons to make a decision when to use which one. massa 16:10, 14 Nov 2004 (UTC)
I am teaching an upper level undergraduate course and graduate course in Chromatography and Mass Spectrometry. Over the years I have not found a suitable textbook and so I am considering using primary resources and these WikiPages as reference points. My students will also be challenged to edit and clarify these pages when possible. If we had other academics do the same thing then this could be a good way to improve the material. '''''R.O'B''''' at UBC Okanagan (talk) 13:53, 20 December 2007 (UTC)RobOBrien
[edit] Chromabarography
This was included in the article by User:Invent, the content needs to be verified, a search for chromabarography on the Web of Science gives no results. Could be a hoax
Chromatography is nothing else than the mirror of analytical chemistry. What do you think, what does the analytical instrumentation-making expect in the near future?
Truly - a new technology!
XXI century puts the task for the qualitative improvement of the possibilities of the chromatographic apparatus. One of them is the new technology of Chromatography - Chromabarography. In the development of chromatography, a process that goes on up to day, a definite tendency is traced. After the substantial theoretical and technological "gush" it follows to provide the equipment with additional parts allowing the enlargement of the analytical possibilities of the chromatograph. On this background it is considered in-time to develop such a rich with its possibilities and effective technology a gas chromatography as Chromabarography - a new basic technology of chromatography.
What does it present itself, what does it give to the user and producer of the equipment?
After all, the heart of chromatography is the chromatographic column. The theory of gas chromatography, presented by the equation of Van Deemter, shows that for each chromatographic separation there exists an optimal flow rate above and below which the column efficiency is reduced. In practice, the linear speed of the sample zone moved by the carrier gas, is changed continuously and increases as it approaches the outlet, which results in a non-effective use of a part of the column. In this case equation characterizes the optimal separation process only in that section of the chromatographic column through which the sample passes at an optional speed.
However the linear speed of the sample zone moving with the carrier-gas can be kept constant by programming the pressure gradient movement along the column in time, realizing the function: pressure - location - time by keeping constant the pressure difference ∆ p at the ends of the chromatographic column during the whole cycle of the analysis (Russia Patent "Chromatograph of A. S. Hayrapetyan").
For the first time in the world this basic technology was worked out and proposed, based on the investigation of the factors of diffusion and kinetics, and includes the meaning "bar-gradient chromatography" or Chromabarography, not included in the standard terminology for gas chromatography of the International Union of Theoretical and Applied Chemistry (IUTAC).
For the realization of the basic technology an equipment was invented and defended by a Russia patent. As a result a maximum possible efficiency (Hayrapetyan's Effect) of column is obtained at a minimum length, which at the same time is optimal as well, as in difference to the ordinary column a further increase in column length increases the analysis time.
These are not the only advantages of Chromabarography. On the contrary, interesting possibilities of its modification have been revealed, which envisage:
A combined application of the moving pressure gradient and temperature (Chromabarothermography)
Or the moving pressure gradient along the column in combination with temperature programming equally inflicted to the whole chromatographic column (Chromabarograph with temperature programming).
- Looks like self promotion or hype for a dubious technology. Google search returns around 700 hits for the term, but a good number on the first pages appear to be hype written by the same person that wrote this - based on style and wording. Several were discussion on blogs or whatever signed by one ARAM HAYRAPETYAN, presumably the inventor of Chromabarography. Many Russian sites on the Google list. If it is real it is yet too new and unverified to include here. -Vsmith 02:03, 31 Jan 2005 (UTC)
Very entertaining, indeed. Packed column supercritical fluid chromatography uses a pressure regulator at the column outlet keeping the pressure constant, should the user so desire, irrespective (within the design limitations of the equipment) of flowrate, mobile phase composition, and temperature. The body governing nomenclature conventions is the IUPAC, International Union of Pure and Applied Chemistry, http://www.iupac.org BTW, the original invention by Tswett (pick your transcription) held the column outlet at constant pressure: it was held at ambient pressure.
[edit] Paper chromatography
Correct me if I'm wrong, but I think that paper chromatography is really a very minor subject in modern chromatography. I don't think it should have such prominence in the article. I can understand how it is good as a demonstration of the principle. If it is actually used in any modern analytic procedures, these should be mentioned. ike9898
- It's used a tiny bit for pigement seperation by some botanists, although TLC would be more commonly used for the same procedure. The paper chromotography section is quite well written, and does clearly explain the principle of chromotography, plus it is a technique that a high-school or undergrad student may come across, so I'd be hesitant to see it cut. Mabye we should add a sentence to say that it is no longer a procedure widely used in labs --nixie 23:28, 15 Feb 2005 (UTC)
As an encyclopedic topic, paper chromatography occupies a critical position in the historic development of the science of chromatography. I support nixie's contention about the quality and relevance of the section. If an edit is needed, it is the moving of the IMAC description to the affinity chromatography section and the drafting of an accurate ion exchange section, arguably one of the most important techniques in the modern chromatographic arsenal. :M Signs 16:49, 11 Mar 2005 (UTC)
[edit] Gas-liquid chromatography
I am I just being biased, or is this a rather cursory, and incorrect (GC is useful for both non-polar and polar compounds--it just depends on what column you use), comment on GC compared to the other sections? On the whole, this article seems to give a bio-researcher's POV of GC. Pi3832 15:34, 22 May 2006 (UTC)
[edit] Structure
Any objections to restructuring the article to make it more organised? It would look a little like this:
Chromatography
- History
- Chromatography theory
-
- Retention
- Plate theory
- Solid-liquid chromatography
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- Affinity chromatography
- Column chromatography
- Ion exchange chromatography
- High performance liquid chromatography
- Normal phase (NP) liquid chromatography
- Reversed phase (NP) liquid chromatography
- Paper chromatography
- Thin layer chromatography
- Size exclusion chromatography
- Liquid-liquid chromatography
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- Countercurrent chromatography
- Gas-liquid chromatography
Or does anyone have any improvements? The whole array of chromatographic techniques on Wikipedia is jumbled and in need of some order -- Serephine ♠ talk - 14:05, 20 June 2006 (UTC)
- Go for it.--Pi3832 16:05, 21 June 2006 (UTC)
I would add capillaryelectrochromatography since it has way more applications and importance in analytical chemistry than some of the applications already included. It would also be nice if there was a section or at least a link to microchip technologies since it happens to be the hottest thing around at the moment. Dv3 19:17, 16 April 2007 (UTC)
[edit] My Recent Edits
Here's the explanation of what I changed:
- 1. Saying that chromatography paper is "dipped" makes it sound like the paper is completely submerged in solvent. This would be disastrous.
- 2. TLC stationary phase is bonded to a substrate, not a carrier. The use of this word here could be confused with, e.g. carrier gas.
- 3. A substances retention time, Rf value, etc. is not definitive proof of its identity. Although it is very useful, spectroscopic methods are always used for further verification.
- 4. In GC, the stationary phase, whether in a capillary or packed column, is always solid. A liquid stationary phase would not stay stationary for very long, especially with a stream of gas flowing over it.
- 5. The entire TLC plate is not made out of silica, so I changed it to say "layer."
I hope you find my edits to be helpful. Mihovil 02:39, 19 September 2006 (UTC)
The physical state of the stationary phase, in the case of open tubular capillary, is actually more like liquid than solid. The layer is very thin and polymeric and it stays in the capillary because of the high surface tension and viscosity of the liquid. Dv3 19:24, 16 April 2007 (UTC)
[edit] Mikhail Semyonovich Tsvet
A user at IP address 66.71.48.70 has repeatedly changed the spelling of "Mikhail Semyonovich Tsvet". The alternate spelling is referenced at the article Mikhail Tsvet. The persistent revision of the spelling in this article seems to be bordering on vandalism. -- Pi3832 00:51, 28 February 2007 (UTC)
- IP user 66.71.58.169 does it also. I concur that it's inappropriate. Can't figure out why we should be using anything other than the guy's own page's name and primary spelling when linking to his page and spelling his name. DMacks 02:26, 28 February 2007 (UTC)
[edit] clc
Someone just asked me about clc. I found this: http://www.polymicro.com/catalog/3_5.htm --Gbleem 05:05, 5 April 2007 (UTC)
[edit] Bees/wasps analogy
I just removed the following comment:
This is the copied form from colby Reynolds (NTI) paper of 2002
from the bees/wasps analogy because it's commentary not encyc content and it's not clear what it even means. If there's a copyright concern for this text, need a complete citation. Conversely, many organic and analytical profs and textbooks use at least one animal-behavior example for teaching chromatography and I've heard bees well before 2002, so I don't think referencing this work to cite the idea is valid. DMacks 18:12, 8 May 2007 (UTC)
[edit] Borax
I just snipped this addition about borax from the Affinity Chromatography sub section:
- You also should be sure to clean all suplies with borax before using, this way the solutions will with hold procedures in a more substansial way.
If it's correct, it might belong in the Affinity Chromatography page, but it's still a bit too technical for any encyclopedia article. Jmeppley 22:25, 26 September 2007 (UTC)
[edit] lizzy
when i was using the black marker i had 2 draw a thick line around the middle surface and the n i had 2 get a cup that was fulled with water and place the tip of the filter into the cup and i left it for about 20 minutes and then all the colors came out, yellow, blue, red, green, purple, and many other colors.Rainbow colors to exact. but i had some difficulty's, the first time that experiment and i put it into the water and left it for about 15 minutes or more it came out gray and black and it was a very faded colors. so i tried it again and then the colors came out and i am still wondering why that format was like that cause i was watching it the hole time and i thought that i was a little bit of color coming out remarkable. I couldn't believe that i had this project 2 do and like so many colors came out and i judged it by its colors. yes i know its not good to do that =). anyway my project was a sudses but all i need 2 do it show it to my class and get my grade. when i do ill get right back to you.discharge —Preceding unsigned comment added by 74.64.65.196 (talk) 15:41, 16 March 2008 (UTC)
[edit] Layman's question
Being an outsider I have to ask for confirmation from an expert: am I wrong in saying that the two groups of applications, a) preparative and b) analytical need different sequential treatment, that is to say that for the preparative purpose the column is chopped to bits for individual testing of its parts, and therefore the analytes stay in the column, whereas for the analytical purpose it is driven through with the solvent so that residence time of each component can be measured by the instruments? If this is the case, then the explanation for the solvent is incorrect. Further, it is not absolutely clear how many words are used for the static phase, and what is the name of the filling support of the static phase, or have I overlooked anything? LouisBB (talk) 05:01, 5 May 2008 (UTC)
- Your understanding of the different applications is not correct. In all cases, either the distance the analyte moves or its residence time is measured to identify the analyte. For analytical purposes, one mainly cares about how much of each analyte is present; for preparative purposes, one mainly cares about recovering a certain analyte. For preparative purposes, cutting apart the column is the least useful thing, because the whole goal is to get the analyte itself, not just see where it is (which is an analytical issue). DMacks (talk) 05:09, 5 May 2008 (UTC)
- Thankyou DMacks for the explanation. Unfortunately to me everything is still not quite clear. What do you mean by saying that the distance of the analyte moves, i.e. per unit time ? In the explanation of column chromatography it is clear that the comumn is not chopped up, but the introduction does not specify how the separate analytes are collected for further use. The definition of the solvent does not say that it is used for carrying the analytes through, rather than to dissolve the sample. Also not that different solvents might be used for carrying different types of compounds through. Is this understanding also incorrect in your view? Then it is still not clear why so many expressions with similar meanings are used under separate entries in the list of terms, static phase, stationary phase, immobilised phase, and what the actual support is called. I am reading the encyclopaedia because I want to learn, so I would like to see clear, compact, concise explanations in the article. Thanks again LouisBB (talk) 12:51, 6 May 2008 (UTC)
