The detection of arsenic using gold-based nano particles platted on screen printed carbon electrode interfaces

S. Vilakazi
Mintek,
South Africa

Keywords: arsenic, gold nanoparticles

Summary:

The detection of arsernic using gold-based nanoparticles platted on screen printed carbon electrode interfaces Abongile N. Jijana*a, Ntsoaki Mputhi*b*, Sibulelo Vilakazi*c National Innovation Centre, Advanced Material Division, Mintek, 200 Malibongwe Drive, Private Bag x 3015, Randburg, South Africa. *e-mail: Sibulelov@mintek.co.za The semiconducting α-lipoic acid capped gold nanoparticles are discussed, the gold nanoparticles were grown at room temperature. These nanocrystals posed a size average spherical crystal diameter of 14.3 nm, confirmed by transmission electron microscopy (TEM) studies. The surface charges around the nanoparticle surface deduced from the Zeta analysis of the gold nanoparticles capped with the α-lipoic acid showed surface charges around -1.03 mV, indicating good dispersion stability. These semiconducting nanomaterials matrices showed good size dependent electron mobility, good electro-activity, electronic conductivity and good optical properties. A band edge (Eg) of 2.1 eV, was obtained for the produced gold nanoparticles. The α-lipoic acid capped spherical gold nanoparticles were further modified with L-Cysteine molecule, which served to recognize the As-heavy metal ion in solution. Surface passivation of the gold nanoparticles with chemical compatible ligands such as amines and carboxylic acids makes them popular in the many application fields. This work reports a unique semiconducting gold nanoparticle based electrochemical sensor for the detection of the As ground water contaminant. The electron induced [(L-cysteine)-(α-lipoic acid)-AuNPs] sensing platform was initially characterized by four redox electron transfer reactions of the inorganic gold core and the inorganic capping layer on their surface, that occurred at formal potentials ( ); 1.34 V, 1.159 V and -0.218 V respectively. These clarifications indicated the moderate electro-activity of the sensing platform. A target limit of detection (LOD) at ppm concentration range was obtained. The use of the square wave voltammetry stripping voltammetry (SWV-ASV) in development of the herein proposed sensor certify the sensing platform high selectivity and binding affinity towards the target arsenic heavy metal ion (HMI). References 1. Bodelón, G., Costas, C., Pérez-juste, J., Pastoriza-santos, I., & Liz-marzán, L. M. (2017). Nano Today Gold nanoparticles for regulation of cell function and behaviour. Nano Today, 13, 40–60. https://doi.org/10.1016/j.nantod.2016.12.014 2. Chithrani, B. D., Ghazani, A. A., & Chan, W. C. W. (2006). Determining the Size and Shape Dependence of Gold Nanoparticle Uptake into Mammalian Cells. 3. Chowdury, M. A., Walji, N., Mahmud, A., & Macdonald, B. D. (2017). Paper-Based Microfluidic Device with a Gold Nano sensor to Detect Arsenic Contamination of Groundwater in Bangladesh. https://doi.org/10.3390/mi8030071 4. Devi, J. M. (2017). Journal of Molecular Graphics and Modelling Simulation studies on structural and thermal properties of alkane thiol capped gold nanoparticles. Journal of Molecular Graphics and Modelling, 74, 359–365. https://doi.org/10.1016/j.jmgm.2017.03.023 5. Dragoe, D., & Sp, N. (2006). Detection of trace levels of Pb 2 + in tap water at boron-doped diamond electrodes with anodic stripping voltammetry, 51, 2437–2441. https://doi.org/10.1016/j.electacta.2005.07.022