Selective recognition of fumarate from maleate with a gold nanoparticle-based colorimetric sensing system

A colorimetric sensing system of gold nanoparticles functionalized with carboxylate-binding units of o-(trifluoroacetyl)carboxanilide is described, which selectively recognizes a trans-dicarboxylate (fumarate) from its cis-isomer (maleate) and several dicarboxylates through inter-particle cross-linking, resulting in an apparent color change from red to purple.