Cheap strong dye with COOH group?

[WS]

Hi DK, 

you mean this: https://secure.wikimedia.org/wikipedia/en/wiki/Fluorescein
"ordinary" Fluorescin? 

Yes, it was my first thought, as you may get it quite cheaply in 
technical quality, even through eBay. I dismissed it quite fast, as I had 
mad "bad" experience with FITC as label in fluorescence microscopy - too 
fast bleaching, when irradiating with blue light from a mercury lamp or 
even 488nm laser. As for now, the main purpose would be tracing an 
organic compund / labelled protein during processing, am I overconcerned 
maybe?

Thanls, 
Wo





> 
> Carboxyfluorescein? Not sure about price. Shouldn't be expensive. Some
> triazine textile and inkjet dyes do come with as carboxy groups. There
> are zillions of them on the market. Not sure how to get structures for
> most of them however.
> 
> DK