Ammonia silver staining

Figure 21.18 Ammonia silver staining of the longitudinal section of mid section of nerves at 14 weeks postimplantation (a) PUCL-oZf-PEG (b) PUCL-ran-PEG (c) autograft (d) PCL (e) silicone.

Other agents are also available, which are used to remove pigmentation of teeth e.g. weak ammonia solution is used to remove iodine stains, hypochlorite or iodine solution are used to remove silver stains, hypochlorites are used to remove iron stains of teeth and for dye stains, chlorinated lime and acetic acid are used. 

Demer, F. R., University of Arizona Lab. Safety Notes, 1990, (Fall), 2 A report of an explosion when mixing an outmoded silver staining reagent involving ammonia which could, and evidently did, form fulminating silver. Use of more modem safe formulations is commended. 

A yellow to brown or black stain is produced,4 which is compared with a set of standard strips prepared under similar conditions. The chief difficulty encountered is to obtain a reliable and permanent set of standards especially is this the case with silver nitrate, the stains of which do not keep. The most satisfactory method5 of preparing such stains is to soak the filter paper in gum tragaeanth, dry it, soak it in silver nitrate solution, again dry it, expose to arsine under the requisite conditions and fix the stain by repeated soaking in very dilute ammonia and coating with paraffin. By the use of 66 per cent, silver nitrate solution, OT x 10-6 g, of As may be detected.6... 

The ammonia produced in the lime test can be detected by indicator papers. Especially effective is filter paper moistened with silver nitrate-manganese nitrate solution. On contact with ammonia, a gray or black fleck appears on the white paper. The stain is due to a mixture of free silver... 

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