Colorimetric and electrochemical arsenate assays by exploiting the peroxidase-like activity of FeOOH nanorods

• Published in: Mikrochimica acta (1966) Vol. 186; no. 11; p. 732
• Main Authors: Zhong, Xiao-Li, Wen, Shao-Hua, Wang, Yi, Luo, Yu-Xi, Li, Zhi-Mei, Liang, Ru-Ping, Zhang, Li, Qiu, Jian-Ding
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.11.2019; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Arsenates; Arsenates - analysis; Benzothiazoles - chemistry; Biomimetic Materials - chemistry; Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Colorimetry; Colorimetry - methods; Drinking Water - analysis; Electric properties; Electrical conductivity; Electrical resistivity; Electrochemical analysis; Electrochemical Techniques - methods; Ferric Compounds - chemistry; Green products; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Lakes - analysis; Limit of Detection; Microengineering; Nanochemistry; Nanorods; Nanotechnology; Nanotubes - chemistry; Original Paper; Oxidation; Peroxidase; Peroxidase - chemistry; Rivers - chemistry; Silver chloride; Substrates; Sulfonic Acids - chemistry; Water Pollutants, Chemical - analysis; Nanozyme; Peroxidase-mimic; Electrochemical analysis; Arsenic; Colorimetric analysis; Iron oxyhydroxide
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-019-3863-1

The authors describe an electrochemical and an optical method for the determination of As(V) by using iron oxyhydroxide (FeOOH) nanorods that display peroxidase-mimicking activity. The nanorods catalyze the oxidation of substrate ABTS by H 2 O 2 to form a green product with an absorption maximum at 418 nm. If, however, As(V) is electrostatically adsorbed on the nanorods, the oxidation is gradually inhibited. A colorimetric assay was worked out based on these findings. Response is linear in the 0 to 8 ppb and 8 to 200 ppb As(V) concentration range, and the detection limit is 0.1 ppb. Even higher sensitivity is achieved in an electrochemical method which is based on the excellent electrical conductivity of FeOOH nanorods. Electrochemical analysis of As(V) was achieved by first adsorbing As(V) on the nanorods. This inhibits the ABTS reduction current signal, best measured at a potential of 150 mV (vs. Ag/AgCl). The linear range extends from 0.04 to 200 ppb, and the detection limit is as low as 12 ppt. Graphical abstract Schematic representation of FeOOH nanorod-based colorimetric and electrochemical assays for arsenate (As(V)). As(V) adsorbed on FeOOH nanorods inhibits the peroxidase-mimicking activity of nanorods, and a colorimetric and electrochemical dual-signal assay was constructed to achieve sensitive determination of As(V).