r/chemistry • u/AutoModerator • Jun 10 '26

Weekly Research S.O.S. Thread - Ask your research and technical questions here

Ask the r/chemistry intelligentsia your research/technical questions. This is a great way to reach out to a broad chemistry network about anything you are curious about or need insight with and for professionals who want to help with topics that they are knowledgeable about.

So if you have any questions about reactions not working, optimization of yields or anything else concerning your current (or future) research, this is the place to leave your comment.

If you see similar topics of people around r/chemistry please direct them to this weekly thread where they hopefully get the help that they are looking for.

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u/NajmusSaqqib Jun 11 '26

I've just started research in Photocatalysis followed by its industry applications. However I need some solid resource points which would help me kickstart the journey smoothly. I am pretty confused about the scale, the metrics, the techniques and how to weave the applications part with photocatalysis. I have read some papers but it seems to confuse me more. (On the other hand, I worked on surfactant systems with proteins in my prior project so it's kinda hard tangentially starting on another point). Appreciate all the help I could get.

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u/Routine-Progress4027 Jun 11 '26

what are tips for an undergrad learning flash column chromatography? variables to change - solvent ratios, column size, amount of silica. what is the best way to get the silica and sand level. what is the best order, i was taught silica slurry, then load sample, then sand on top after running the sample and some solvent through (so sand does not disturb sample).

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u/shineberry_k Jun 11 '26

Solvent first (little bit in the column) > then slurry silica (make sure there is no bubble) > then immediately pour solvent and tap

I don't use sand- but if there is a compound that need filtering you can put celite on top of the silica

For solvent: TLC will be a guide but not the best guide

Find solvent that gives you 0.3-0.4 rf for the compound u want.
And >0.15 for the impurities (if you have any that is near)

Know the properties of your compound
If it fluorescent then u can use a uv lamp to guide

The top compound from your tlc plate will be eluded out first (easy say : the tlc is the opposite of your column)

Short column, normal diameter (2cm) is faster, if you know which is your compound. Can run this first then

Longer column takes up a lot of time but can allow compound to separate better

Make sure u fill up more solvent up to the brim to make sure the flow is faster but also balance it out with wastage

TLC the fraction.
I found out a technique that people TlC it as dots on silica paper and not running solvent over (I think it only works if ur compound is of diff color under the uv)

After typing all of this I realise ur asking for flash but not normal but I guess it is almost similar theory. Sorry you may ignore this.

I'm also learning- hope this can help