A novel colorimetric strategy for sensitive and rapid sensing of ascorbic acid using cobalt oxyhydroxide nanoflakes and 3,3′,5,5′-tetramethylbenzidine

• DOI: 10.1016/j.snb.2017.10.070
• Publication Date: 2017-11-05T22:04:38Z
• Authors: Danyang Ji; Yahui Du; Hongmin Meng; Lin Zhang; Zhongming Huang; Yalei Hu; Jianjun Li; Fei Yu; Zhaohui Li
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract In this work, cobalt oxyhydroxide nanoflakes (CoOOH nanoflakes) were reported to possess a high oxidizability toward TMB for the first time and based on which we have developed a new strategy for qualitative and quantitative detection of ascorbic acid (AA). In our design, CoOOH nanoflakes can directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to oxTMB with an obvious blue color emerging, and AA can selectively inhibit the oxidation of TMB to oxTMB by resolving CoOOH nanoflakes to Co2+, resulting in a decrease in the absorbance of oxTMB and bleaching of blue color. As such, the concentration of AA could be identified very easily by UV–vis spectroscopy and bare eyes. Under optimal conditions, this sensing platform showed a highly sensitive response to AA with a detection limit of 142 nM and a short assay time of 5 min. This assay was also successfully used to quantify AA in human serum samples and practical food samples. Importantly, using this fabricated sensing strategy, we have further developed a paper-based strip sensor for AA detection with satisfactory results, showing its great potential for point of care applications.