4-Aminothiophenol functionalized gold nanoparticles as colorimetric sensors for the detection of cobalt using UV-Visible spectrometry

The 4-aminothiophenol functionalized gold nanoparticles (4-ATP-Au NPs) were used as colorimetric sensors for the detection of Co2+ in aqueous solution by using UV-Visible spectrometry. The 4-ATP-Au NPs were characterized by UV-Visible, FT-IR, TEM and dynamic light scattering (DLS) which confirmed their higher binding affinity towards Co2+ through coordinate covalent interactions that can be observed with the naked eye. The absorbance ratio (A(570)/A(523)) was linear with Co2+ concentration in the range of 15 x 10(-3) to 1 x 10(-3) M with a correlation coefficient of (R (2)) 0.994, and the limit of detection was 5.79 x 10(-5) M.