Antifade Mixtures for Fluorescence Microscopy are media for mounting preserved samples that will be viewed by fluorescence microscopy. These mixtures serve several purposes:

There are do-it-yourself simple formulations that are inexpensive and easy to prepare, and there are a number of proprietary products that may have specific advantages for their stated purpose. For example, some media give a lower initial fluorescence intensity, but the subsequent rate of photobleaching is much lower, giving a more stable fluorescence for measurements.

Common DIY Antifade mixtures.
These mixtures are prepared by simply mixing the ingredients until dissolved (several hours to overnight) and filtering or centrifuging. They are stored dark at room temperature (or colder, to -20C), and appear to be stable for several years. A search of the Microscopy Society of America Listserver Archives  will find a number of contributions on this subject. From that source, Peter Sargent (comparing  DABCO, phenylene diamine, n-propyl gallate, Vectashield, and Slow Fade) determined that 4% n-propyl gallate in 90% glycerol and 10% PBS was the best he tested; slides are reputed to keep for weeks to years in dark at -20C.

Proprietary Antifade Products.

Molecular Probes   >>
ProLong(r) Antifade Kit -  claimed to be best by Molecular Probes
Slow Fade(r) -  slides keep 2-3 months in dark @ 4 C.

Vector Laboratories  >>
Vectashield, Vectashield Hard-set

The Central Microscopy Facility  >>
The University of Massachusetts at Amherst, MA, USA