Biuret reagent was used to stain wool fibers with copper so the location of a small amount of poly(methyl acrylate) grafted onto the fibers could be determined by energy dispersive x-ray microanalysis of copper. The grafted polymer was determined to be located in regions of the fibers where cuticle had been previously damaged. The amount of grafted polymer present was too small for secondary electron imaging to be useful for locating the polymer grafts.
Bresee, R. R. and Annis, P. A.
"Biuret Staining and X-Ray Microanalysis for Locating Grafted Poly(Methyl Acrylate) on Wool Fibers,"
Scanning Microscopy: Vol. 3
, Article 10.
Available at: https://digitalcommons.usu.edu/microscopy/vol3/iss3/10