Synthesis of water soluble chitosan stabilized gold nanoparticles and determination of uric acid
Thi Lanh Le, Quang Khieu Dinh, Thai Hoa Tran, Hai Phong Nguyen, Thi Le Hien Hoang and Quoc Hien Nguyen
Abstract
Gold nanoparticles (Au-NPs) have been successfully synthesized by utilizing water soluble chitosan as reducing and stabilizing agent. The colloidal Au-NPs were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The results showed that the colloidal Au-NPs had a plasmon absorption band with maximum wavelength in the range of 520–526 nm and the diameters were about 8–15 nm. In addition, a new Au-NPs-modified electrode was fabricated by self-assembling Au-NPs to the surface of the L-cysteine-modified glassy carbon electrode (Au-NPs/L-Cys/GCE). The Au-NPs-modified electrode showed an excellent character for electro-catalytic oxidization of uric acid (UA) in 0.1 mol L−1 phosphate buffer solution (pH 3.2). Using differential pulse anodic stripping voltammetry (DP-ASV), a high selectivity for determination of UA has been explored for the Au-NPs-modified electrode. DP-ASV peak currents of UA increased linearly with their concentration at the range of 2.0 × 10−6 to 4.0 × 10−5 mol L−1 with the detection limit of 2.7 × 10−6 mol L−1 for UA. The proposed method was applied for the detection of UA in human urine and serum samples with satisfactory results
