Citifluor Permafix-1 (HRF)
Citifluor Permafix-1 (HRF) is an aqueous solution of a chemically modified poly(vinyl alcohol) containing additives for use as a permanent mountant having a high refractive index (~1.52). The solution may be used with either Citifluor AF100 or Citifluor AF200 where it is important to reduce the photo bleaching of fluorochromes (see Application Sheets for Citifluor AF100 and Citifluor AF200 for details) but dilution with these solutions will reduce the refractive index of the dried films. Citifluor Permafix-1 HRF should only be used with specimens that have been fixed i.e. the biopolymers have been cross linked. The additives in the formulation will dissolve linear proteins etc. leading to problems with obtaining good images.
A few drops of the solution should be applied to the specimen followed by a cover slip. Evaporation of the water leads to formation of a clear film which holds the cover slip in place thereby aiding the safe storage of the specimen.
The solutions are of medium viscosity and are water-white in appearance. They contain a small amount of sodium azide to prevent fungal growth. They may be stored at room temperature. The cap of the bottles should always be replaced after use, to prevent evaporation of water which leads to film formation and ultimately to solidification of the product. Samples stored under these conditions for 6 months have been found to exhibit little apparent deterioration e.g. no gel formation.