Questions tagged [chromatography]
collective term for a set of laboratory techniques for the separation of mixtures
286
questions
7
votes
1
answer
2k
views
Why are amber bottles used to store Water for HPLC?
Image Source: https://www.calpaclab.com/water-hplc-spectro-grade-4-liter-bottles-case-4/ted-ws2211-001
When ordering HPLC/Spectro grade Water for HPLC from certain vendors(not all), it comes in an ...
- 1,528
4
votes
1
answer
351
views
Meaning for chromatography terms linear velocity and volume flow rate
I am learning about chromatography and there are two terms that confuse me a lot: linear velocity and volume flow rate. These terms are defined in Daniel Harris's Qualitative Chemical Analysis:
...
- 600
3
votes
0
answers
122
views
What could lead to exaggerated positive LC-MS/MS test for tetrahydrocannabinol?
I was driving with the car and was involved in a minor traffic violation and I was submitted to a drug saliva test. The sample was analysed in the laboratory using liquid chromatography with tandem ...
- 31
2
votes
0
answers
43
views
TLC experiment interprentation
I am having difficulty interpreting the results of an identification test involving six different standards (dyes) in an unknown mixture of dyes, using silica gel TLC plates and acetone as the mobile ...
- 17
0
votes
0
answers
37
views
Need Suggestion for Picking the Right Solvent for Column Chromatography
I've completed my reactions, and based on the stoichiometry and TLC analysis, I think my mixture should contain 3-4 compounds:
Ethyl gallate (my product)
Gallic acid (the reagent/starting material)
...
- 155
0
votes
1
answer
47
views
Aliphatic alcohol analysis in capillary gas chromatography
4.5. Standard solutions of trimethylsilyl ethers of aliphatic alcohols from C20 to C28.
They may be prepared from mixtures of pure alcohols at the time they are required for
use.
Reference solution ...
- 1
1
vote
0
answers
61
views
Why this problem happens on LC-MS chromatogram?
I used to analyse my compounds on LC-MSdevice with 95% water/5% acn +0,1 formic acid. My column is hypersilgold (C18). When I did my acquisition, I obtain this chromatogram sometimes, and it doesn't ...
1
vote
1
answer
123
views
Making an UV inactive salt UV active during purification of charged anion with HILIC purification?
In the context of a purification setup I am asking myself the question: Can a UV inactive charged substance made be UV active by a counter ion that absorbs UV light during a column run?
If so, when no ...
- 779
14
votes
4
answers
3k
views
Does molten metal liquid chromatography exist?
Liquid chromatography is used to analyze and purify different chemical samples in a solvent. It is also used for industrial scale chemical purification. I was wondering if something similar exists for ...
- 651
-1
votes
1
answer
59
views
Thin layer Chromotography Separation
I am confused about the basic understanding when it comes to TLC. I was under the assumption that less polar compounds move farther on the plate due to it having fewer IMFs. But I also heard that a ...
1
vote
0
answers
62
views
How can I isolate products that cannot be cleanly distilled or visualised by TLC for column chromatography?
I am a first year PhD student in the UK, and without giving too many details of my work as it is industrially funded and my sponsors are a bit touchy over IP, I am struggling to isolate the products ...
- 11
2
votes
0
answers
80
views
When is chromatography regarded as a viable industrial purification strategy?
I understand the basics that chromatography is a fairly slow and expensive process compared to direct synthesis. When a synthesis route is not feasible, the economics become favorable. Not being in ...
- 651
3
votes
1
answer
155
views
Are there LCMS compatible buffer systems available for the high pH range 12-14?
I want to perform chemical stability studies for different pH Values. To achieve pH Values from 1 to 6 I can prepare solutions with trifluoric acid and formic acid and ammonium formate and acetate. I ...
- 779
1
vote
0
answers
70
views
"Is there any library in Python or software for analyzing raw chromatography data?"
I have taken the data directly from the FID sensor using a DAQ, so I have the chromatography data in this format:
(2 data colummns in a txt file) (18000 rows)
Time (s) Intensity (V)
0.00367___0.0008
...
- 27
2
votes
0
answers
48
views
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 ...
- 21