Questions tagged [chromatography]
collective term for a set of laboratory techniques for the separation of mixtures
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How do I calculate the masses of compounds in a mixture from a GC?
I'm supposed to analyse the two GC graphs in the attached picture (I quickly drew them instead of taking a picture). The question states ths "A mixture contains 3-Methylhexane. To determine the ...
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Regression equation for peak fronting/tailing in chromatography
Background
I would like to have a sum of functions $$\sum_{i=1}^k f_i(x)$$ which approximates my chromatogram. The variable $x$ would be my retention time, although I don't mind if answers change it ...
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Term for one chromatography sample affecting the next?
Suppose I am running a collection of samples on a chromatograph (gas or liquid) in some order. Some of the sample molecules have large retention times due to their size and/or interactions with each ...
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When creating a separation method in gas chromatography, calibration with compounds mixture or for each separate component?
When creating a separation method in gas chromatography, is there any difference between the calibration with the compounds mixture and the calibration for each separate component? I have 5 components....
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How to effectively replace DMSO with LC–MS-compatible solvent for the samples from a well plate?
I want to do LC–MS analysis of the samples from a 384-well plate where each compound (at around 1–10 μM) is dissolved in 10–15 μL of DMSO. I am worried about the DMSO dwarfing the analyte’s signal, as ...
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Is there any reason why KMnO4 for TLC is stored under basic condition?
my mentor told me that the KMnO4 solution specifically for TLC has added some bases like sodium hydroxide but we don't know why. I try to search on google, and found that the bases are usually by-...
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How to interpret gas chromatography results?
I am having trouble interpreting gas chromatography (GC) results for the production of ethyl acetate from acetic acid and ethanol. I am trying to find the reaction order from these results, as well as ...
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How can I approximate the actual HPLC gradient?
In High Performance Liquid Chromatography (HPLC), the actual gradient is a bit different from the true gradient programmed because of dwell volume and other effects. For example, in the figure added, ...
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How to choose the solvent gradient for the flash column chromatography of a complex mixture?
When performing a flash column chromatography, it is advised to select an eluent in which the desired compound has an $R_\mathrm{F}$ of about $0.25$ in TLC.
However, if I want to separate and isolate ...
user78790
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How does industry separate glucose from fructose using liquid chromatography when producing high-fructose corn syrup?
Can someone explain how the separation of glucose and fructose is achieved using liquid chromatography in the industrial production of high-fructose corn syrup?
I've seen references to ion-exchange ...
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Trouble analyzing amine using GC-FID
I am trying to analyze a sample containing hexamethylenediamine (HMD) dissolved in ethanol using GC-FID for an undergraduate chemical engineering project. The column used is Agilent DB-FFAP (high ...
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Dynamic equilibrium of Girard T-derivatized oxysterols
This is a question relating to organic chemistry, moreso than chromatography.
I am running LC-MS on various hydroxycholesterols (HC) and dihydroxycholesterols (diHC). To increase ionization efficiency ...
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Why I am unable to detect nystose & kestose using hplc and refractive index detector while could see peaks of glucose,sucrose,fructose, and raffinose [closed]
Mobile phase is 60% acetonitrile and temperature of the column is 25 degrees (supercosil amino from sigma). RID is also set up at 25.
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Mystery GC peak appearing between 1H2 and various molecular combinations of 1H, 2H and 3H?
The following gas chromatograph, taken from "Review of the different techniques to analyse tritium", labels all but the largest peak. Given that the analyte is likely to be from some source ...
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Why will changing the solvent crack the column for column chromatography?
When we perform column chromatography with silica to purify the reaction crude product, we sometimes need to change the solvent system to better extract our target product.
For example, changing from ...
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