Urine for plasmonic nanoparticle-based colorimetric detection of mercury ion.

Urine for diagnostics: Urine, a "green" natural product, is used as an active component to produce a simple, inexpensive, and portable colorimetric Hg(2+) sensing assay with high selectivity and sensitivity by simply mixing gold nanoparticles (AuNPs) and urine. The synergetic effect of uric acid and creatinine decorated on AuNPs is the reason for selective binding of Hg(2+) , leading to the aggregation of gold nanoparticles and thereby causing a visible color change.