Deare Kait,

It is assumed that the silver stain is dependent upon the presence of per-

iodate-sensitive cis-glycols in the core and side- chain polysaccharide of the LPS molecules.

For further reading I would suggest going through the attached papers.

Hope that helps.

Best-

Silver nitrate salt forms black stain when come in contact with skin and the stain is due to the chemical reaction of Ag+ ion. That is why this salt is mainly used to detect voters during election in many countries including Pakistan.