The fabrication and application of nanostructured gold used for electrochemical detection of environmental contaminants

• Main Authors: Ying-Yao Tang, 湯瑩瑤
• Other Authors: Po-Yu Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/82654960894684556058

碩士 === 高雄醫學大學 === 醫藥暨應用化學研究所 === 99 === In this study, three different gold nanostructures with electrocatalytic activity or high surface area were fabricated for the electrochemical detection of environmentally hazardous compounds. Gold nanoparticle deposited-indium tin oxide electrode (ITO/AuNP) was fabricated by potential-sweeping or potential-step electrodeposition in acidic aqueous solutions. ITO/AuNP shows higher sensitivity than other common electrodes in the determination of p-nitrophenol and the dependence of the steady state current taken from hydrodynamic chronoamperogram on the concentration of p-nitrophenol was linear from 1.0 × 10–7 M to 3.15 × 10–4 M with a regression coefficient of 0.9995. The detection limit was 9.8 × 10–8 M (13.7 ppb) (S/N = 3). Nanoporous gold coated-ITO electrode (ITO/NPG) was obtained by dealloying Ag from AuAg alloys electrodeposited from aqueous media. ITO/NPG possesses excellent stability and sensitivity due to its high surface area and each pore behaves like an electrochemical thin layer cell. For hydrazine determination, the ITO/NPG electrode shows a wide dynamic range (5.00 × 10-9 M to 2.05 × 10-3 M) and the detection limit is 4.37 × 10-9 M (S/N = 3) which is the lowest detection limit found in recent reports. To obtain the nanopore-assembled macroporous gold-coated ITO (ITO/NP-MPG), AuAg alloys were first electrodeposited into the interstitial spaces between the polystyrene (PS) latex spheres which self-assembled to form the template and then the PS spheres and Ag element were removed in sequence by using tetrahydrofuran (THF) and concentrated nitric acid. Noteworthily, the nanopore structures only promote the electrocatalytic activity for the hydrazine and the detection of another environmental contaminant such as diquat is more easily achieved by using ITO/NP-MPG electrode.