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“Oxidative etching-aggregation” of silver nanoparticles by melamine and electron acceptors: An innovative route toward ultrasensitive and versatile functional colorimetric sensors

Wang, Guang-Li, Zhu, Xiao-Ying, Jiao, Huan-Jun, Dong, Yu-Ming, Wu, Xiu-Ming, Li, Zai-Jun
Analytica chimica acta 2012 v.747 pp. 92-98
colorimetry, detection limit, hydrogen peroxide, iron, melamine, nanosilver, ozone
An innovative and versatile functional colorimetric sensor for melamine (MA) and H₂O₂ was developed with simplicity, excellent selectivity and ultrasensitivity. The detection mechanism was based on the “oxidative etching-aggregation” of silver nanoparticles (AgNPs) by the cooperation effect of MA and electron acceptors such as H₂O₂, ozone or Fe(NO₃)₃. The detection limits of this method for MA could reach as low as 0.08nM, 0.16nM and 3nM when H₂O₂, ozone or Fe(NO₃)₃ was used as an electron acceptor, respectively. When using H₂O₂ as a typical electron acceptor, the method enabled the detection of H₂O₂ with a detection limit of 0.2nM. This proposed method offered a new way to design MA and H₂O₂ sensors and might be easily extended to detect other nucleophilic reagents and electron acceptors based on colorimetric sensors.