Help with FITC - (Jun/22/2009 )

How long can a FITC-labeled sample be stored in 4C? I need to use it to label bacteria. Thx!

Nrelo on Jun 22 2009, 06:02 AM said:

You can't store it at -80*C, I take it (in which it could last years) or at -20*C (probably a few months) I take it?

At 4*C I wouldn't give it more than a week, two if you're feeling lucky. Most fluorophores will quench reasonably quickly at 4*C, and FITC is no exception.

-Carlton

Nrelo on Jun 22 2009, 12:02 PM said:

You don´t mention what your "sample" is!
The amount of time that you can store your material depends mostly on the stability of the unlabeled "sample".
Provided you protect against bacterial/fungal growth and maintain in the dark, FITC-proteins are very stable (provided that the unlabeled material is stable under the same storage conditions).

For example, commercial FITC-immunoglobulin conjugates usually have a recommended 4 oC "shelf-life of >1 year. I am, at present, using home made FITC-antibodies to CD33 and CD34 which have been stored in our fridge for > 3 years.

It is usually a good idea to give old conjugates a high-speed spin or 0.22 filter occasionally in order to remove any aggregates.

Hope this helps.

commercially FITC labeled DNA / RNA is stable for years at -20°C, and for months at 4°C in my hands

phillp

FITC stored in dark and in cold should be fine for quite sometime but ur bacteria gonna die. Fixing might help.

Nabi on Jul 2 2009, 09:48 AM said:

yes i will fix them for confocal

Thx all!

By the way, does anyone have any idea at what pH is FITC stable at? I found this paper online that talks about FITC's stability in different conditions but I am unable to download it since the paper is from 1965.

I am working with a peptide conjugated with FITC and I am using it as a detection reagent. So far, there has been no positive shift in fluorescence for my samples as compared to the control.. Trying to work on the buffer conditions etc.

jiajia1987 on Jul 3 2009, 02:35 AM said:

Try the paper request forum. Someone there may be able to get you a copy.

I have a similar question about FITC. I am using it without conjugating it to anything, just as an indicator of pH in an aqueous environment. There are no proteins or other biological molecules in the system. I understand FITC decomposes in water and ethanol is a better solvent for making a stock solution, but it will eventually be used in an aqueous system. Does anyone know how fast it decomposes in water? Will I lose a significant amount of fluorescence in about 2.5 hrs? Since I am using it as an indicator, the data I use is the measured fluorescence intensity, so a drop in fluorescence is a big issue for me.

Thanks!