Questions tagged [chromatography]
collective term for a set of laboratory techniques for the separation of mixtures
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Normal phase vs reverse phase HPLC
What is the difference between normal phase and reverse phase high-performance liquid chromatography?
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TLC monitoring of Buchwald-Hartwig coupling reaction using ninhydrin stain
I am conducting a synthesis involving Buchwald-Hartwig coupling reaction. The reagents are 2,3,5-tribromothiophene, 1-aza-18-crown-6, NaOtBu as base, $\ce{Pd_2(dba)_3}$ as palladium source, DavePhos ...
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What is the state of stationery phase in paper chromatography?
As per my textbook:
Partition Chromatography: Partition chromatography is based on continuous differential partiotioning of components of a mixture between stationary and mobile phases. Paper ...
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How do I find Rf values & length size of paper in chromatography?
A student is designing an experiment using paper chromatography. From previous results, she knows that the Rf values for two dyes that she wishes to investigate are 0.72 and 0.80.
It is proposed that ...
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What inference can be made from the fact that there is no reversal in how three components eluate?
I gave an answer this question about TLC. I now realize that I am blundering my way through this question.
The problem statement doesn't specify if the compounds to be eluted are polar or non-polar. ...
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Diffusion/Streaky bands on TLC plate
These days I am working on a research project where I am supposed to run TLC for samples which are wax extracts from coconut butten nuts using chloroform as the solvent. All the samples have been ...
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How do I perform thin-layer chromatography to identify alkaloid content in fruits?
Fruits and as well as other plant parts usually contain alkaloids, which are nitrogenous compounds. I'd like to know how the Thin-Layer Chromatography method can be used to determine the alkaloid ...
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Does every solute spend at least $t_M$ in the mobile phase?
In 'Fundamentals of Analytical Chemistry' 9th edition by Skoog, West, Holler and Crouch, there is the following passage (page 865).
The dead time (void time), $t_M$, is the time it takes for an ...
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Does ninhydrin staining detect triethylamine?
My reaction mixture has amine compounds, so it shows tailing in bare silica plates. Therefore I decided to add small amount of triethylamine in the eluent. Because my amine compound is not detected by ...
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The Principle of Internal Standardization (in the context of ion chromatography)
I am trying to grasp how internal standardization works in principle, and I am having some trouble wrapping my head around it. It is not the choosing of an IS I think about, orwhen it might benefit ...
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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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Quantitative information from silica gel TLC plate?
I have a general question about thin-layer chromatography using silica gel.
Can we get quantitative information from a TLC analysis? Is this mainly just the Rf or can we tell more? I'm guessing ...
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Retention time and dead time
Why does ts start just after tm ?
Does the analyte starts spending time in the stationary phase only after the mobile phase has passed and reached the detector ?
Wouldn't there be an overlap between ...
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How does the polarity of the eluent and sample affect the Rf value in thin layer chromatography?
A three-component mixture (X, Y, Z) was separated using normal phase TLC. Three eluents of varying polarity were used. Select the TLC plate that was developed using the least polar eluent (click on ...
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