Spectrophotometric detection of uric acid with enzyme-like reaction mediated 3,3 ',5,5 '-tetramethylbenzidine oxidation

WO3 nanosheets (NSs) were prepared and characterized by X-ray photoelectron spectrometer (XPS), X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The obtained WO3 NSs exhibited peroxidase-like catalytic activity, which can catalyze H2O2 to oxidize 3,3 ',5,5 '-tetramethylbenzidine (TMB) to generate oxidized TMB (oxTMB) with an absorption peak centered at 652 nm. Based on this, a facile method for the spectrophotometric determination of H2O2 was established. Under the selected conditions, the increase in absorbance of oxTMB enabled the detection of H(2)O(2 )ranging from 2.0 to 180 mu M. Considering the fact that H(2)O(2 )is one of the products of urate oxidase (UAO)-catalyzed uric acid (UA) oxidation, a convenient method for the selective determination of UA was further developed with the help of UV-Vis spectrophotometer. The increase of absorbance at 652 nm showed a linear response to UA concentration over the range of 2.0-180 mu M. The limit of detection for UA was as low as 1.25 mu M. More importantly, the proposed method was applied to the determination of UA in serum samples with satisfactory results.