Wurster test

Wur·ster test

(vūr'ster),
an obsolete test for tyrosine in which a substance is dissolved in boiling water and quinone is added. If tyrosine is present, a ruby-colored reaction takes place, and the solution turns brown after a few hours.

Wurster,

Casimir, German chemist, 1856-1913.
Wurster reagent - filter paper impregnated with tetramethyl-p-phenylenediamine, which turns blue in the presence of ozone or hydrogen peroxide.
Wurster test - for tyrosine.