Colorimetric detection of thiocyanate based on anti-aggregation of gold nanoparticles in the presence of cetyltrimethyl ammonium bromide

A facile, highly sensitive and selective colorimetric strategy for thiocyanate (SCN-) detection is proposed based on anti-aggregation of gold nanoparticles (AuNPs) which was induced by surfactant cetyltrimethyl ammonium bromide (CTAB). A certain concentration of aggregation agent CTAB is responsible for a visible color change of AuNPs from wine red to blue. The aggregations of AuNPs decrease with increasing concentrations of SCN-, which can be monitored by an ultraviolet-visible spectrophotometer or the naked eyes. The limit of the detection (LOD) is 0.1 mu M by the naked eyes and 6.5 nM by UV-vis spectroscopy with the linear range from 0.1 to 1.5 mu M. The applicability of our detection system is also verified by analysis of SCN- in milk samples and satisfactory results were obtained. (C) 2015 Elsevier B.V. All rights reserved.