The oxidase-like activity of iridium nanoparticles, and their application to colorimetric determination of dissolved oxygen

• DOI: 10.1007/s00604-017-2326-9
• Publication Date: 2017-05-16T02:48:27Z
• Authors: Malin Cui; Yuan Zhao; Chan Wang; Qijun Song
• Keywords: 02 engineering and technology; 0210 nano-technology

Iridium nanoparticles (IrNPs) with intrinsic oxidase-like activity were synthesized by using sodium citrate as the stabilizer and NaBH4 as the reducing agent. The IrNPs have an average diameter of 2.5 ± 0.5 nm and exhibit excellent oxidase-like property. Under the catalytic action of the IrNPs, 3,3′,5,5′-tetramethylbenzidine (TMB) is oxidized by dissolved oxygen (DO) to form a blue product with an absorption maximum at 652 nm. The catalytic activity is ascribed to the production of superoxide anion radical (O2ˉ∙). The chromogenic reaction is exploited for the determination of DO. The method exhibits a wide calibration range from 12.5 to 257.5 μM of DO and a limit of detection as low as 4.7 μM. Compared to other methods, this method presented here shows improved precision and faster response time.