Hello everyone,

Just getting into making up my own TLC plates to avoid the extra cost and waste of buying them online and I'm wondering if I will need a fluorescent compound in the mix to identify compounds on the plates.

I've been looking around online but I can't seem to find much information on the fluorescent indicators companies use in their plates. I stumbled upon some information about "Fluorescene" as a reagent indicator after chromatography, but I'd like the plates to work like the commercial TLC plates available online, which have the fluorescent indicator impregnated in the plate.

I'm currently using a mix of Calcium Sulfate as the binder and Silica for the mobile phase painted (**not literally painted, more like poured**) onto glass plates.

If anyone with experience in making their own plates, or TLC of common alkaloids in general, could shed some light on this for me I'd greatly appreciate it.

Also, I wonder, is the fluorescence of the plate even necessary when working with Tryptamine/Phenethylamine/Indole alkaloids?


Thanks for having me,
Chert


Edit: "**" Avoiding "paint vs pour" confusion.

You'd have to be sure your fluorescine wasn't soluble in your solvent system. Considering it's used for tracing leaks in drainage systems, it seems like this would be a bit tricky.

Perhaps someone who knows what the fluorescent substance in commercial plates is could chime in. It has to be insoluble in a wide range of solvents so I'm thinking some kind of fluorescent (rare earth?) metal oxide is most likely. The coating from inside a fluorescent lighting tube might do the job but then you have to be wary of mercury residues.

Heyo,

@downwardsfromzero - Interesting idea, this may be the case. I was able to find out what manufacturer's actually use in their plates, It's called "F245". Other than that I can't seem to find what this actually means. I'm guessing the 245 in the name relates to a spectrum but still haven't found anything relating to the actual identity of the compound, or mixture.

Thank you for your input!

Overall it seems most of the known alkaloids of interest are actually fluorescent at around 300-500nm (commercially available black lights are sufficient here), so this indicator is kind of irrelevant in that aspect.

Most of my interest pertains to lesser known compounds, so in that case ill just have to buy the impregnated disposables until the identity of f245 is revealed.

F254 appears to be zinc silicate

https://broadpharm.com/w...uct.php?catalog=BP-12212

You can buy it by itself, or you can buy silica gel powder with f254 already added, so you can mix with water and pour your own plates. That's how we used to make our prep tlc plates.

You don't need f254 necessarily. If you are using developing agents that cover all of your compounds of interest, then you don't need it.
I think it's a waste to make your own plates, and not have f254 included, as it's able to help you visualise so many compounds.

Hey thanks a bunch, leratiomyces!

Thanks for clearing that up. I'll heed your warning and try to source some of that fluorescent silica then. It seems the additive would be helpful in identifying other compounds present that aren't fluorescent, even if the target compound/species is.

Very much appreciated
Chert