Gold Microelectrode Array Research Articles

Amperometric Differential Determination of Ascorbic Acid in Beverages and Vitamin C Tablets Using a Flow Cell Containing an Array of Gold Microelectrodes Modified with Palladium

A simple and attractive method for quantification of ascorbic acid (AA) in beers, soda, natural juices and commercial vitamin C tablets was achieved by combining flow injection analysis and amperometric detection. An array of gold microelectrodes electrochemically modified by deposition of palladium was employed as working electrode which was almost unaffected by fouling effects. Ascorbic acid was quantified in beverages and vitamin tablets using amperometric differential measurements. This method is based on three steps involving the flow injection of: (1) the sample plus a standard addition of AA, (2) the pure sample, and (3) the enzymatically-treated sample. The enzymatic treatment was carried out with Cucumis sativus tissue, which is a rich source of ascorbate oxidase, at pH 7. The calibration plots for freshly prepared ascorbic acid standards were very linear in the concentration range of 0.18–1.8 mg L−1 with a relative standard deviation (RSD) < 1%, while for real samples the deviations were between 2.7 % to 8.9 %.

Highly sensitive heavy metal analysis on platinum‐ and gold‐ultramicroelectrode arrays

AbstractThe use of platinum‐and gold‐ultramicroelectrode arrays for heavy metal analysis is described. The noble metal microelectrodes are structured with standard silicon technologies. The geometry of the electrode array is varied and optimized in regard to the microelectrode characteristic. Mercury film formation and–dissolution on platinum microelectrode arrays is characterized and compared with iridium electrodes of the same geometry. Gold microelectrode arrays are shown to be useful for mercury detection. The repeated use of the sensors has been studied. Optimizing the electrode gemoetry and the stripping procedure results in detection limits down to the ng/L range.

Flow-through Cell Based on an Array of Gold Microelectrodes Obtained From Modified Integrated Circuit Chips

M. A. Augelli, V. B. Nascimento, J. J. Pedrotti, I. G. R. Gutz and L. Angnes, Analyst, 1997, 122, 843 DOI: 10.1039/A701519D

A gas-humidity sensor fabricated with phthalocyanine Langmuir-Blodgett film

Langmuir-Blodgett films of a symmetrically substituted copper phthalocyanine were deposited onto planar interdigital gold microelectrode arrays designed specially with a heating resistor. Measurements on this device showed that it could be used as a humidity sensor at room temperature, and as a gas sensor when it was heated by heating the resistor. Either as a humidity or gas sensor, it exhibits high sensitivity, rapid response and good stability. It has excellent selectivity to NH 3 as a gas sensor.

Photoelectrolysis of water on a titanium dioxide/platinum microelectrode array

Interdigited electrode arrays (IDA) have been studied so far in reference to the development of chemical microtransistors and sensors as well as to high performance measurements of redox intermediates based on a platinum, silver or gold microelectrode array [1-4]. Recent advances in microfabrication techniques allow preparation of IDA with various chemical functions in addition to the role as an electrode array itself. A possible candidate is a semiconductor-based IDA where both photochemical and electrochemical control of reactions along the array can be expected. As an example, we fabricated a TiO2/Pt microelectrode array and studied the effects of spatial arrangement of the electrodes on the photoelectrochemistry of TiO 2. Although the photochemistry of TiO 2 particles has been studied extensively [5-7], the effects of spatial distribution of Pt or P t /RuO 2 sites on the photocatalytic activity of TiO 2 particles have been discussed very little. In this note, we report that the photocurrent on a TiO 2 microelectrode accompanied by photodecomposition of water is markedly enhanced by applying a potential to a Pt microelectrode arranged in the vicinity of the TiO 2 electrode. The results are discussed in terms of diffusion of OHions across the array and subsequent band bending of the depletion layer in TiO2 by OH-.

Voltammetry at linear gold and platinum microelectrode arrays produced by lithographic techniques

Voltammetry at linear gold and platinum microelectrode arrays produced by lithographic techniques