Patent ID: 7745153

Claim:
A protein assay reagent composition comprising pyrocatechol violet at a concentration from about 0.1 mM to about 0.5 mM; a metal at a concentration from about 0.05 mM to about 0.4 mM; polyvinyl alcohol at a concentration from about 0.05% w/v to about 0.4% w/v; optionally methanol at a concentration from about 0% v/v to about 10% v/v, polyvinyl pyrrolidone at a concentration from about 0.05% w/v to about 0.2% w/v, a buffer at a concentration from about 25 mM to about 200 mM, and at least one of a chelator at a concentration from about 0.05 mM to about 2 mM, or sodium benzoate at a concentration from about 1 mM to about 6 mM, wherein the pH of the protein assay reagent composition is from about pH 1 to about pH 4.