The use of fluorescent labels and markers is widespread and immunofluorescence, which relies on the use of antibodies tagged with labels such as fluorescein, is a well-established technique. A common problem associated with the microscopical examination of these materials is that the illumination used for stimulating the fluorescence also causes degradation of the label and this causes fading of fluorescence. This is also a problem when trying to visualise materials having a low level of labelling. The photofading of labelled materials can be retarded by the use of the Citifluor mountants. They are also useful for rhodamine and DAPI.

The antifadent solutions AF1, 2 and 3 were specifically developed for use with FITC polyclonal antibodies but their use is now far more widespread. They show improved signal preservation with many other fluorochromes, including rhodamines and DAPI.AF4 contains the antifadent n-propyl gallate, which is particularly suitable for use with DAPI and Alexa dye-stained materials, as well as FITC-labelled materials

• AF1
  Glycerol phosphate buffered solution containing antifadent for use with labelled tissue sections and dead cells. The solution has a pH of approximately 10. Available in two sizes.
   
• AF2
  Glycerol solution containing antifadent for use with labelled tissue sections and dead cells. The solution has a pH of approximately 10. Available in two sizes.
• AF3
  Phosphate buffered saline solution containing antifadent for examination of whole live cells. The solution has a pH of approximately 10. Available in two sizes
   
• AF4
  Glycerol solution containing n-propyl gallate for use with labelled tissue sections and dead cells. An aqueous solution (75% AF4 and 25% water) has a pH of 5.

Cultures of purified cortical astrocytes with rabbit antisera against glial fibrillary acidic protein, a component of the astrocyte cytoskeleton. The rabbit antisera was visualised using fluorescein-conjugated sheep anti-rabbit 1 g antisera.

Micrographs courtesy of Mark Noble, Institute of Neurology, London. The first visual shows fluorescent using glycerol as the mountant media The second visual shows fluorescent using Citifluor (Glycerol/PBS) as the mountant media

After 15 seconds illumination

After 1 minute illumination

After 3 minutes illumination