A simple assay for azide surface groups on clickable polymeric nanoparticles

The surface azide content of polymeric nanoparticles (latex) was measured in three steps: 1) conjugating an alkyne derivative of Rhodamine (Rho-Alk); 2) using paper chromatography to separate the immobile latex particles from unreacted fluorophore; and, 3) on-paper fluorescence quantification of the latex-bound Rho-Alk. Paper chromatography with methanol elution was effective because the nanoparticles did not migrate during elution, whereas the …