Flower-like self-assembly of gold nanoparticles for highly sensitive electrochemical detection of chromium(VI)

Abstract

We report here the fabrication of a flower-like self-assembly of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) as a highly sensitive platform for ultratrace Cr(VI) detection. Two AuNPs layers are used in the current approach, in which the first is electroplated on the GCE surface as anchors for binding to an overcoated thiol sol-gel film derived from 3-mercaptopropyltrimethoxysilane (MPTS). The second AuNPs layer is then self-assembled on the surface of the sol-gel film, forming flower-like gold nanoelectrodes enlarging the electrode surface. When functionalized by a thiol pyridinium, the fabricated electrode displays a well-defined peak for selective Cr(VI) reduction with an unusually large, linear concentration range of 10–1,200 ng L−1 and a low detection limit of 2.9 ng L−1. In comparison to previous approaches using MPTS and AuNPs on Au electrodes, the current work expands the use of AuNPs to the GCE. Subsequent functionalization of the secondary AuNPs by a thiol pyridinium and adsorption/preconcentration of Cr(VI) lead to the unusually large detection range and high sensitivity. The stepwise preparation of the electrode has been characterized by electrochemical impedance spectroscopy (EIS), scanning electronic microscopy (SEM), and IR. The newly designed electrode exhibits good stability, and has been successfully employed to measure chromium in a pre-treated blood sample. The method demonstrates acceptable fabrication reproducibility and accuracy.

Sol–gel derived gold nanoparticles biosensing platform for Escherichia coli detection

“…Recent reports [39] from other authors also confirm that AuNPs are integrated in 3D polymeric networks containing thiolated groups. Furthermore, we have analyzed by AFM at higher resolution those areas where the nanoparticles form aggregates at the surface ( figure 2A).…”

Electrochemical Determination of Chromium(VI) in River Water with Gold Nanoparticles-Graphene Nanocomposites Modified Electrodes

“…Graphene/ AuNPs/GCE also offered excellent repeatability with a relative standard deviation (RSD) of about 1.70% for 5 repeated measurements of 5.00 μM Cr(VI). Compared with previously published methods with gold based electrodes, [10][11][12][13][14][15][16][17][18] the Graphene/ AuNPs/GCE offers the advantages of a satisfied detection limit, convenient detection procedures and simple electrode preparation, which fulfills the requirement for potential practical applications.…”

“…Gold nanoparticles (AuNPs) or nanostructured gold modified electrodes have been developed due to their favorable characteristics in the enhancement of electron-transfer processes with respect to the polycrystalline gold electrode. [10][11][12][13][14][15][16][17] The graphene-based nanomaterials is also being used for electrochemical sensing applications with greater frequency because of unique properties, such as high conductivity, excellent mechanical property and large active surface area. [18][19][20][21][22][23] A modified electrode with AuNPs and graphene nanocomposites for the detection of Cr(VI) was first reported by Santhosh and coworkers.…”

A Self‐assembled L‐Cysteine and Electrodeposited Gold Nanoparticles‐reduced Graphene Oxide Modified Electrode for Adsorptive Stripping Determination of Copper

“…However, due to the strong van der Waals interaction, the graphene sheets tend to form agglomerates, and even restack to form graphite, which significantly reduce the effectiveness of graphene [18]. AuNPs are another widely used material in electrochemistry, owing to their superior biological compatibility, excellent catalytic property and conducting capability [19][20]. The introduction of AuNPs in graphene sheets is an effective way to prevent the formation of agglomerates [21].…”