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Sensors 2016, 16(5), 626;

A Rapid In Situ Colorimetric Assay for Cobalt Detection by the Naked Eye

Biotechnology Research Division, Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Research Institute (KAERI), 29 Geumgu-gil, Jeongeup, Jeonbuk 56212, Korea
Department of Chemical Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, 100 Inha-ro, Incheon 22212, Korea
Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea
These authors contributed equally to this work.
Authors to whom correspondence should be addressed.
Academic Editors: Jong Seung Kim and Min Hee Lee
Received: 25 March 2016 / Revised: 24 April 2016 / Accepted: 26 April 2016 / Published: 2 May 2016
(This article belongs to the Special Issue Colorimetric and Fluorescent Sensor)
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A simple, rapid, and convenient colorimetric chemosensor of a specific target toward the end user is still required for on-site detection and real-time monitoring applications. In this study, we developed a rapid in situ colorimetric assay for cobalt detection using the naked eye. Interestingly, a yellow to light orange visual color transition was observed within 3 s when a Chrysoidine G (CG) chemosensor was exposed to cobalt. Surprisingly, the CG chemosensor had great selectivity toward cobalt without any interference of other metal ions. Under optimized conditions, a lower detection limit of 0.1 ppm via a spectrophotometer and a visual detection limit of 2 ppm with a linear range from 0.4 to 1 ppm (R2 = 0.97) were determined. Moreover, the CG chemosensor is reversible and maintains its functionality after treatment with chelating agents. In conclusion, we show the superior capabilities of the CG chemosensor, which has the potential to provide extremely facile handling, high sensitivity, and a fast response time for applications of on-site detection to real-time cobalt monitoring for the general public. View Full-Text
Keywords: cobalt; colorimetric; chemosensor; on-site detection; naked eye cobalt; colorimetric; chemosensor; on-site detection; naked eye

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Kang, S.-M.; Jang, S.-C.; Kim, G.Y.; Lee, C.-S.; Huh, Y.S.; Roh, C. A Rapid In Situ Colorimetric Assay for Cobalt Detection by the Naked Eye. Sensors 2016, 16, 626.

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