A fast nonenzymatic sensor for measuring uric acid in biological fluids has been developed by David Parker and coworkers at Durham University, in England (Chem. Commun. 2006, 4084). Currently, enzymatic methods are used to measure uric acid, high levels of which are associated with gout and kidney disease. But these methods are slow and subject to interference by other compounds. The Durham method uses a mixture of luminescent lanthanide complexes consisting of terbium or europium ions with a common macrocyclic ligand (shown; Ln = Tb or Eu, R = NHC(CO2-)CH2CH2CO2-). The excited states of the complexes are quenched selectively by electron transfer from urate anions, and the urate concentration is determined from the green/red light intensity ratios of the Tb/Eu complexes. This ratiometric method internally compensates for interference effects that occur to the same extent for both complexes. The analysis is carried out using fluorometers and multiplate readers--equipment that is commonly available in analytical labs, Parker notes.