Sciencemadness Discussion Board

difference between fluorescent and non-fluorescent tlc plates

soma - 5-8-2016 at 22:23

I recently got some tlc silica plates that were supposed to have fluorescent indicator in them. I compared them under the 254 uv to plates that didn't have indicator and there was no difference.

Are they supposed to glow?

Thanks.

[Edited on 6-8-2016 by soma]

unionised - 6-8-2016 at 09:17

They are supposed to glow under UV light.
Something like this is typical
http://www.chem-ilp.net/labTechniques/TLC.htm

NEMO-Chemistry - 6-8-2016 at 12:47

Are you sure of the wave length you used? I have both a short wave and a long wave UV light (black lights are longer wave), the plates only glow on short wave lengths.

Easiest way i have seen to tell from the tube is to look at it, short wave is normally clear glass and each end has a short curly wire at each end.

Longer wave lengths are often opaque or black tubes and the ends are different in the tubes.

soma - 6-8-2016 at 15:25

I recently bought a led flashlight on ebay that was advertised as being 254nm uv. I've also got a blacklight.

This is the ad for the tlc plates. If the picture is supposed to represent it, it seems like they don't have the uv indicator. (The ad says they do.) http://www.ebay.com/itm/112033870854

NEMO-Chemistry - 7-8-2016 at 01:26

Can you see the light from the torch? I think its likely the torch is not what it says it is. The wavelength you need is not good to look at, Or maybe its just not got enough power.

My UV light is something like 3-5W

Fulmen - 7-8-2016 at 02:45

The images confuses me, the plates are dark while the spots fluoresces.

unionised - 7-8-2016 at 04:56

The fluorescent plates are quite bright when lit with 254 nm UV but they don't fluoresc at all when lit with 366nm (or longer).
So the picture may well show F254 plates, lit by 366 nm light and causing the materials on the plates to light up.

I suspect tiaht your 254nm torch was misdescribed.

soma - 7-8-2016 at 22:27

This is the torch - it was recommended by XeonTheMGPony
http://www.ebay.ca/itm/UV-LED-torch-250nm-curing-glue-solder...