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J Nanopart Res (2014) 16:2728 DOI 10.1007/s11051-014-2728-0
RESEARCH PAPER
Plasmonic sensing of CTAB in gold nanorods solution based on Cu(II) ions-mediated H2O2 etching effect
Guojun Weng Jianjun Li Jian Zhu
Junwu Zhao
Received: 2 July 2014 / Accepted: 1 November 2014 / Published online: 13 November 2014 Springer Science+Business Media Dordrecht 2014
Abstract Hexadecyltrimethylammonium bromide (CTAB) acts not only as a stabilizer but also as the template in the seed-mediated growth approach, which is signicant to the successful preparation of gold nanorods. However, the concentration of CTAB is difcult to determine in gold nanorods solution, especially in the gold nanorods colloids cleaned by centrifugation. In this paper, we have developed a simple, selective, and sensitive plasmonic sensing method for determination of the CTAB concentration in gold nanorods solution by Cu(II) ions-mediated H2O2 etching effect. In this sensing, gold nanorods were employed as optical probes, which showed strong longitudinal plasmon band (LPB). The CTAB participated oxidization makes H2O2 etch gold nanorods along the long axes. The catalyzed etching leads to the length of gold nanorods being short, resulting in blue shift of the LPB and the sequential color changes. Under the optimal experiment conditions, the blue shift of LPB was proportional to the concentration of CTAB in the ranges of 140 mM, with a good correlation coefcient of 0.9865. The recoveries of the CTAB in gold nanorods solution samples ranged from 98.36 to 115.42 %. Therefore, the proposed nano-sensor was demonstrated to be simple, sensitive, and selective,
providing an effective alternative for sensing of CTAB in gold nanorods solution.
Keywords Gold nanorods (Au NRs)
Hexadecyltrimethylammonium bromide (CTAB)
Plasmon etching Nanoprobes Noble metal
nanostructure
Introduction
The charming size-dependent properties of noble metal nanostructures have created a great prospect for their application in wide elds, such as electronics, optics, catalysis, and biomedicine (Burda et al. 2005; Giljohann et al. 2010; Saha et al. 2012). Gold nanorods have received signicant attentions due to their unique optical properties and easy synthesis (Lohse and Murphy 2013; Vigderman et al. 2012). Compared to gold nanospheres, gold nanorods have two separate surface plasmon resonances (SPR) bands, known as the transverse and longitudinal SPR peaks, corresponding to their electrons oscillated along the short and long axes of the rods (Link et al. 1999). The...