Preparation of glassy carbon electrode modified by hydrophobic gold nanoparticles and its application for the determination of ethamsylate in the presence of cetyltrimethylammonium bromide

Glassy carbon electrode modified by hydrophobic gold nanoparticles was prepared by simply and rapidly attaching octadecylamine-capped gold nanoparticles onto the glassy carbon electrode surface (denoted as C18NH2-Nano-Au/GCE), which was characterized by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR)-FTIR. The electrocatalytic oxidation of ethamsylate on the C18NH2-Nano-Au/GCE was investigated by means of cyclic voltammetry. The experimental results showed that the octadecylamine-capped gold nanoparticles exhibited a better electrocatalytic activity to ethamsylate, which reduced the oxidation overpotential about 66 mV with obviously increased current response. Under the optimal conditions, there was a good linear relationship between anodic peak current and ethamsylate concentration in the range of 1.0 × 10−8 to 1.0 × 10−5 M with the detection limit of 3.5 × 10−9 M (S/N = 3) in the presence of cetyltrimethyl ammonium bromide (CTAB) by differential pulse voltammetry. The anodic peak current of successive 20 measurements on the identical surface and the renewed ones (n = 10) of C18NH2-Nano-Au/GCE were examined with the relative standard deviation of 3.1% and 3.9%, respectively. It indicated that the chemically modified electrode showed good stability and reproducibility. The proposed method has been used to determine the ethamsylate concentration in biological fluids with satisfactory results.