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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Hachiko on June 16, 2019, 02:40:30 AM

Title: TLC and Fluorescence
Post by: Hachiko on June 16, 2019, 02:40:30 AM

Could we detect an organic compound by TLC with UV lamp if it is not fluorescent?

Title: Re: TLC and Fluorescence
Post by: AWK on June 16, 2019, 02:59:29 AM

You may use many visualizing agents.

Title: Re: TLC and Fluorescence
Post by: Hachiko on June 16, 2019, 03:14:15 AM

Sorry for my unclear question, I mean using UV lamp to detect non-fluorescent compound. So there is no way for UV lamp to detect this kind of compound?
This compound contains some of aromatic rings, could you recommend appropriate visualizing agent for this?

Title: Re: TLC and Fluorescence
Post by: AWK on June 16, 2019, 03:27:41 AM

Some chromatographed compounds quench the indicator fluorescence and in this way become visible.

Title: Re: TLC and Fluorescence
Post by: Hachiko on June 16, 2019, 03:44:36 AM

Thank you for your advice, but could you give some detail methods? I know about chemical stain but it's efficient used for some oxidizable groups or unsaturated bonds.

Title: Re: TLC and Fluorescence
Post by: AWK on June 16, 2019, 03:53:39 AM

https://www.chemistry.mcmaster.ca/adronov/resources/Stains_for_Developing_TLC_Plates.pdf
Most books on TLC give more recipes.

Title: Re: TLC and Fluorescence
Post by: Hachiko on June 16, 2019, 05:05:46 AM

Thank you so much.

Title: Re: TLC and Fluorescence
Post by: Babcock_Hall on June 16, 2019, 12:52:54 PM

Compounds with aromatic rings quenched fluorescence in my experience, but perhaps there are exceptions.  If you have other functional groups, perhaps we could help select a stain.

Title: Re: TLC and Fluorescence
Post by: Hachiko on June 17, 2019, 01:30:00 AM

Sorry, I may get misunderstanding about mechanism of TLC monitor under UV light. So a non-fluorescent compound is also visible as a dark spot under UV light if it absorbs the UV light, is it? And a fluorescent compound is visible as a colored spot depending on the wavelength of fluorescence under UV light.

Title: Re: TLC and Fluorescence
Post by: rolnor on June 17, 2019, 06:30:52 AM

Quote from: awesomesynthesis on June 17, 2019, 01:30:00 AM

Sorry, I may get misunderstanding about mechanism of TLC monitor under UV light. So a non-fluorescent compound is also visible as a dark spot under UV light if it absorbs the UV light, is it? And a fluorescent compound is visible as a colored spot depending on the wavelength of fluorescence under UV light.

Yes

Title: Re: TLC and Fluorescence
Post by: Hachiko on June 19, 2019, 03:28:30 AM

Thank you all.