Questions tagged [chromatography]
collective term for a set of laboratory techniques for the separation of mixtures
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Dark smudge at the TLC solvent front
I have recently started using TLC in my graduate work to test for the cleavage of a cyclic oligo-adenylate in an enzymatic reaction. The sample I'm spotting on my plate is in an aqueous solution ...
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Has anyone added dyes to a mixture about to separated by chromatography in order to visualize where the desired product lies?
Usually in preparative chromatography one needs to know when the desired substance to be separated is coming down the pike. Often this required some sophisticated instrumentation. But, it occurred to ...
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Gas chromatography of samples containg water
I have read a few articles where it is stated that samples containing water are detrimental for a GC experimental results and equipment.
For example, in the paper Identification of essential oil ...
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Why is Ion Exchange Chromatography done in a column?
It seems like the idea of Ion Exchange Chromatography is to get a maximum amount of exposure of your gel to your solution. It seems like overhead stirring and a gel bed would be more likely to be ...
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Optimal lipophilic solvent for washing PEEK-lined reversed-phase HPLC columns
What would be the reasonable strategy for washing a reversed-phase (RP) octadecylsilyl (ODS) C18 HPLC columns from lipids and other non-polar residues? The columns are used for biochemical analysis of ...
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What is the function of thin layer in thin layer chromatography?
I just learned about the thin layer chromatography, which I think is basically the same as the paper chromatography.
I am wondering what is the function of the thin layer? I mean, what's special about ...
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Impact of flow rate on peak areas in Mass Spectrometry
As a follow up to the discussion in comments: it's now clear that UV peaks will have larger area if flow rate is decreased, because the same portion of molecules are measured again and again.
With ...
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Analysis of reaction mixture by TLC and finding column chromatography condition
I am conducting an organic synthesis. Below is the TLC image.
I used dichloromethane:methanol:triethylamine=10:1:0.15 as eluent, but I stored it during 3 days, so it may be a little bit concentrated.
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Is it possible to run column chromatography in reversed phase?
I'm conducting a synthesis involving aza-crown-ether.
Whether aza-crown-ether acts as a base or not is unclear, but when I do TLC using dichloromethane/methanol, it is hardly drawn up with the mobile ...
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Reason for GC peak splited
I ran GCMS and one of the peak of GC appears:
The peak shows some tailing, but there seems to be another peak at right-hand end of the signal. I have already checked the MS and confirmed that there ...
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Can the paper in thin layer chromatography be any type of paper?
I'm doing a chemistry chromatography lab that wants me to recreate anything I want. I decided to measure how far a pigment goes in each color for the same brand, but I'm stuck at the paper part. I ...
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Normal phase dead time marker
In reverse-phase HPLC, Thiourea, Uracil, Nitromethane or $\ce{KNO3}$ are used as dead time markers because of their polarity and therefore weak interactions with the stationary phase. However, I could ...
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Why is Retention factor for Iodide greater than Bromide?
I did a separation of Bromide and Iodide ions using paper chromatography technique for 0.3% solutions of Bromide and Iodide of sodium. I got the Retention factor equal to ~0.71 for Iodide and ~0.47 ...
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Is it possible to functionalize silica gel as Activated Carbon can be? How?
Activated carbon and Silica gel both have a high surface area.
If I understand correctly it is possible to trap stuff inside activated charcoal pores to give it specific retention properties (by ...
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Comparing retention time of acetic acid, salicylic acid and acetylsalicylic acid in HPLC
I want to compare retention time of acetic acid(AA), salicylic acid(SA) and acetylsalicylic acid(ASA) in HPLC. What are the factors do I have to consider when comparing? Considering dipole moment only,...
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