Noise at microelectrodes and microelectrode arrays in amperometry and voltammetry

Long, John T.; Weber, Stephen G.

doi:10.1021/ac00171a032

Cited by 27 publications

(26 citation statements)

References 27 publications

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“…Our results also demonstrate that, despite previous suggestions 2, 25, 33 , capacitive loading of the amplifier (e n C noise) is not the dominant noise source for amperometric measurements using microelectrodes as further discussed in Supplemental Information. Shot noise and thermal noise due to the diffusional or “Warburg” impedance are also not important noise sources under common recording conditions (also further elaborated in Supplemental Information).…”

Section: Discussionsupporting

confidence: 55%

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Quantification of noise sources for amperometric measurement of quantal exocytosis using microelectrodes

Yao

Gillis

2012

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Electrochemical microelectrodes are commonly used to record amperometric spikes of current that result from oxidation of transmitter released from individual vesicles during exocytosis. Whereas the exquisite sensitivity of these measurements is well appreciated, a better understanding of the noise sources that limit the resolution of the technique is needed to guide the design of next-generation devices. We measured the current power spectral density (SI) of electrochemical microelectrodes to understand the physical basis of dominant noise sources and to determine how noise varies with the electrode material and geometry. We find that the current noise is thermal in origin in that SI is proportional to the real part of the admittance of the electrode. The admittance of microelectrodes is well described by a constant phase element model such that both the real and imaginary admittance increase with frequency raised to a power of 0.84 – 0.96. Our results demonstrate that the current standard deviation is proportional to the square root of the area of the working electrode, increases ~linearly with the bandwidth of the recording, and varies with the choice of the electrode material with Au ≈ carbon fiber > nitrogen-doped diamond-like carbon > indium-tin-oxide. Contact between a cell and a microelectrode does not appreciably increase noise. Surface-patterned microchip electrodes can have a noise performance that is superior to that of carbon-fiber microelectrodes of the same area.

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Section: Discussionsupporting

confidence: 55%

“…Nevertheless, capacitive loading noise can be a dominant noise source for electrochemical electrodes with areas substantially larger than what are generally used for recording quantal exocytosis (> ~ 3000 μm 2 , see Supporting Information and references. 10, 25 …”

Section: Resultsmentioning

confidence: 99%

Quantification of noise sources for amperometric measurement of quantal exocytosis using microelectrodes

Yao

Gillis

2012

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“…We observed a qualitative correlation that electrodes with large CNT agglomerations were highly noisy (S/N <10). The large surface area of an agglomeration likely leads to a large capacitive current; however, the noise increases more than the signal because only a small portion of the surface area is accessible to the analyte 31,32 . SEM images of non-functionalized CNT modified electrodes showed impurities and a large number of agglomerations (Supplemental Fig.…”

Section: Resultsmentioning

confidence: 99%

Functional groups modulate the sensitivity and electron transfer kinetics of neurochemicals at carbon nanotube modified microelectrodes

Jacobs

Vickrey

Venton

2011

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107

108

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The surface properties of carbon based electrodes are critically important for the detection of biomolecules and can modulate electrostatic interactions, adsorption and electrocatalysis. Carbon nanotube (CNT) modified electrodes have previously been shown to have increased oxidative sensitivity and reduced overpotential for catecholamine neurotransmitters, but the effect of surface functionalities on these properties has not been characterized. In this study, we modified carbon-fiber microelectrodes (CFMEs) with three differently functionalized single-wall carbon nanotubes and measured their response to serotonin, dopamine, and ascorbic acid using fast-scan cyclic voltammetry. Both carboxylic acid functionalized and amide functionalized CNTs increased the oxidative current of CFMEs by approximately 2–6 fold for the cationic neurotransmitters serotonin and dopamine, but octadecylamine functionalized CNTs resulted in no significant signal change. Similarly, electron transfer was faster for both amide and carboxylic acid functionalized CNT modified electrodes but slower for octadecylamine CNT modified electrodes. Oxidation of ascorbic acid was only increased with carboxylic acid functionalized CNTs although all CNT-modified electrodes showed a trend towards increased reversibility for ascorbic acid. Carboxylic acid-CNT modified disk electrodes were then tested for detection of serotonin in the ventral nerve cord of a Drosophila melanogaster larva, and the increase in sensitivity was maintained in biological tissue. The functional groups of CNTs therefore modulate the electrochemical properties, and the increase in sensitivity from CNT modification facilitates measurements in biological samples.

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“…These materials have been studied for a wide variety of applications: from electrochemical detectors to biosensors [15][16][17]. Conducting particles + polymer composite materials are widely used in industry in low density metal structures and also as negative electrode materials in batteries [18].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical dissolution and passivation of nickel powder randomly dispersed in a graphite + polypropylene matrix

et al. 2006

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Nickel powder (10% in weight) randomly dispersed in a graphite (40%) + polypropylene (50%) matrix was studied as a composite electrode in a sulphuric-sulphate acid medium by means of voltammetry and Electrochemical Impedance Spectroscopy (EIS). Under voltammetric conditions, this thermoplastic material shows an electrochemical behaviour similar to nickel metal. However, under EIS measurement conditions the electrodissolution behaviour of the nickel powder is partially limited by the diffusion of the anions in the electrolyte in order to electroneutralize the excess of electrogenerated positive charge. The low frequency range of the measured impedance spectra can be interpreted as a parallel arrangement of a capacitive and a Warburg impedance, instead of a CPE element initially considered in the fitting. Values for CPE exponents lower than 0.85 are interpreted as a competition between a capacitive/transport contribution to the overall impedance response.

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Noise at microelectrodes and microelectrode arrays in amperometry and voltammetry

Cited by 27 publications

References 27 publications

Quantification of noise sources for amperometric measurement of quantal exocytosis using microelectrodes

Quantification of noise sources for amperometric measurement of quantal exocytosis using microelectrodes

Functional groups modulate the sensitivity and electron transfer kinetics of neurochemicals at carbon nanotube modified microelectrodes

Electrochemical dissolution and passivation of nickel powder randomly dispersed in a graphite + polypropylene matrix

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