Colorimetric and electrochemical arsenate assays by exploiting the peroxidase-like activity of FeOOH nanorods
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ORIGINAL PAPER
Colorimetric and electrochemical arsenate assays by exploiting the peroxidase-like activity of FeOOH nanorods Xiao-Li Zhong 1 & Shao-Hua Wen 1 & Yi Wang 1 & Yu-Xi Luo 1 & Zhi-Mei Li 1 & Ru-Ping Liang 1 & Li Zhang 1 & Jian-Ding Qiu 1,2 Received: 18 May 2019 / Accepted: 19 September 2019 # Springer-Verlag GmbH Austria, part of Springer Nature 2019
Abstract 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 H2O2 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. Keywords Nanozyme . Arsenic . Iron oxyhydroxide . Peroxidase-mimic . Colorimetric analysis . Electrochemical analysis
Introduction The pollution of arsenic (As) in natural water has become one of the major threats to human health [1]. Continues intake of As can cause central nervous system disorders and cardiovascular diseases [2]. According to the World Health Organization (WHO), the standard level of As in drinking water is 10 ppb (130 nM) [3]. In natural groundwater and terrestrial environments, arsenic with the predominant form of arsenite (As(III)) and arsenate (As(V)). Although As(III) is considered to be more toxic than As(V) [4], the presence of As(V) in the environment is more extensive, especially in the environment with high oxygen content. More than that, the arsenate structure is similar to phosphate, the presence of Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-019-3863-1) contains supplementary material, which is available to authorized users. * Jian-Ding Qiu [email protected] 1
College of Chemistry, Nanchang University, Nanchang 330031, China
2
Engineering Technology Research Center for Environmental Protection Materials and Equipment of Jiangxi Province, Pingxiang University, Pingxiang 337055, China
arsenate can disrupt some phosphate-dependent metabolic processes, which can replace phosphorus in the body and cause arsenic poisoning [5]. There are some considerable efforts dedicating for the development of selective and sensitive arsenic detection methods. Various analytical techniques, including high-performance liquid chromatography (HPLC) [6], atomic absorption spectrometry (AAS)
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