Intrinsic peroxidase-like activity of rhodium nanoparticles, and their application to the colorimetric determination of hydrogen peroxide and glucose

Tatiana G Choleva; Vasiliki A Gatselou; George Z Tsogas; Dimosthenis L Giokas

doi:10.1007/s00604-017-2582-8

Intrinsic peroxidase-like activity of rhodium nanoparticles, and their application to the colorimetric determination of hydrogen peroxide and glucose

Mikrochim Acta. 2017 Dec 5;185(1):22. doi: 10.1007/s00604-017-2582-8.

Authors

Tatiana G Choleva¹, Vasiliki A Gatselou¹, George Z Tsogas¹, Dimosthenis L Giokas²

Affiliations

¹ Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece.
² Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece. dgiokas@cc.uoi.gr.

PMID: 29594622
DOI: 10.1007/s00604-017-2582-8

Abstract

The intrinsic peroxidase-like activity of rhodium nanoparticles (RhNPs) and their use as catalytic labels for sensitive colorimetric assays is presented. RhNPs catalyze the oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H₂O₂ to produce a blue reaction product with a maximum absorbance at 652 nm. Kinetic studies show catalysis to follow Michaelis-Menten kinetics and a "ping-pong" mechanism. The calculated kinetic parameters indicate high affinity of RhNPs for both the substrate TMB and H₂O₂. In fact, they are better than other peroxidase mimicking nanomaterials and even the natural enzyme horseradish peroxidase. On the other hand, RhNPs exhibit no reactivity towards saccharides, thiols, amino acids and ascorbic acid. Based on these findings, a sensitive and selective colorimetric method was worked out for the determination of H₂O₂ in real samples with a linear response in the 1-100 μM concentration range. By employing glucose oxidase, the glucose assay has a linear range that covers the 5 to 125 μM glucose concentration range. The detection limits are <0.75 μM for both species. The methods were applied to the determination of H₂O₂ in spiked pharmaceutical formulations, and of glucose in soft drinks and blood plasma. Figures of merit include (a) good accuracy (with errors of <6%), (b) high recoveries (96.5-103.7%), and (c) satisfactory reproducibility (<6.3%). Graphical abstract Rhodium nanoparticles catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H₂O₂ to produce a blue reaction product. The effect is exploited in photometric assays for hydrogen peroxide and glucose.

Keywords: 3,3,5,5-Tetramethylbenzidine; Blood plasma; Hygiene products; Peroxidase-mimetics; Rhodium; Soft drinks; Spectrophotometry.