Questions tagged [chromatography]
collective term for a set of laboratory techniques for the separation of mixtures
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Using Hydrogen as a carrier gas for a GC; consideration of reactivity with analytes
In many cases people use H2 as a carrier gas for a GC. But does this exclude analysis of (say) systems with unsaturation or aromatic compounds etc. If a analysis uses a temperature program say up to ...
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Determining volume of hydrogen gas evolved in water splitting reaction
I want to carry out a photocatalytic water spliting reaction. This reaction will generate Hydrogen and Oxygen gas in 2:1 ratio according to the following reaction -
2H2O + energy (light) → 2H2 + O2
So,...
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What is the correct unit of a RI detector used for HPLC analysis?
I analyze sugar compounds in soft drinks with HPLC using refractive index detection (RID) on Agilent 1260 Infinity Binary LC (System User Guide (PDF)). I am not sure which unit to put next to the $y$-...
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Finding unknown concentration using HPLC standard curve
I calculated a standard curve equation from a given concentration and peak area, which gave me $y=1994.6x+218.4$. I made the graph with the $x$-axis μg/mL and $y$-axis peak area.
The question is, a ...
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Chromatography and Height Equivalent to a Theoretical Plate (HETP)
HETP can be expressed in two ways:
HETP = L/N
HETP = A + B/u + Cu
where:
L: lenght of the coloumn
N: Number of theoretical plates
A: Eddy-diffusion parameter, related to channeling through a non-...
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How to change the counterion of a nucleotide salt?
I need to take the sodium nucleotide salts I have available in my lab and modify them to instead contain some more exotic counterions. Can I do this by binding my nucleotides to a strong anion ...
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Synthetic resin method to remove permanent hardness of water [closed]
Why is $\ce{R-SO3H}$ first treated with NaCl and then the RNa form i.e., the sodium form of resin is used for treating hard water? Why cannot we directly treat hard water with $\ce{R-SO3H}$? What is ...
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How does having a basic stationary phase help the separation of acidic/basic compounds from non acidic/basic ones?
I have to reason whether silica or alumina would be a better choice of stationary phase for separating a mixture of pyridine and cyclohexanone with column chromatography.
I would expect both pyridine ...
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How to minimize sample dispersion during spotting for paper electrophoresis?
I am separating highly polar amino acids and their derivatives using paper electrophoresis. This requires pre-wetting a piece of filter paper with electrophoresis buffer (in this case, carbonate-...
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What matters for ion exchange: net or local charge?
I am interested in separating two small organic molecules by ion exchange chromatography.
Following the example set by several old papers for these molecules, I want to use a cation exchanger. Both ...
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What's a good high precision analysis technique (after GC) to measure trace isopropanol in water samples?
Looking to measure trace IPA content in water samples.
Only GC I have access to doesn't take samples with water. Different columns not an option.
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Mixture is eluted too early from alumina in flash column chromatography
I have recently tried to purify my reaction mixture by column chromatography. Because my reaction mixture had poor resolution in silica-based TLC, I used neutral alumina-based TLC plate. After I ...
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Why does column chromatography not work like it's supposed to?
I'm a few months into working in an organic synthesis lab and I consider myself to have a solid intuition for, well, how chemistry works. I have ran at least 50 columns at this point but no matter ...
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Decomposable solvent identification in GC-FID
How can a gas chromatography with flame ionization detection (GC-FID) be used to identify a liquid solvent that decomposes at its boiling point like DMSO? In a solution with other higher boiling ...
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Activating alumina before column chromatography
Recently I synthesized some amine compounds, and because it showed better separation in the neutral alumina TLC plates than silica plates, I am planning to purify the reaction mixture using neutral ...
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