The Limits of Aqueous Hot-Wire Electrochemistry: Near-Critical and Supercritical Fluids in Electrochemical Sensors?

Gründler, Peter; Degenring, Daniela

doi:10.1002/1521-4109(200105)13:8/9<755::aid-elan755>3.0.co;2-7

Cited by 24 publications

(6 citation statements)

References 10 publications

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“…Further reduction of the electrical noise associated with the ohmic polarization of the microwire was achieved by connecting the microwire to the potentiostat in the middle point between two power line contacts. It was possible to maintain the surface temperature of the hot-wire electrode below the boiling point of the solution for an indefinite time or well above the boiling point for a short time (e.q., in aqueous solutions, a surface temperature of 250 °C was maintained for ∼5 ms without boiling the solution). However, to provide a large temperature change, high currents up to 6 A had to be used .…”

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confidence: 99%

Hot Microelectrodes

Barański

2002

Anal. Chem.

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Heat generation at disk microelectrodes by a high-amplitude (few volt) and high-frequency (0.1-2 GHz) alternating voltage is described. This method allows changing electrode temperature very rapidly and maintaining it well above the boiling point of solution for a very long time without any indication of boiling. The size of the hot zone in solution is determined by the radius of the electrode. There is no obvious limit in regard to the electrode size, so theoretically, by this method, it should be possible to create hot spots that are much smaller than those created with laser beams. That could lead to potential applications in medicine and biology. The heat-generating waveform does not electrically interfere with normal electroanalytical measurements. The noise level at hot microelectrodes is only slightly higher, as compared to normal microelectodes, but diffusion-controlled currents at hot microelectrodes may be up to 7 times higher, and an enhancement of kinetically controlled currents may be even larger. Hot microelectrodes can be used for end-column detection in capillary electrophoresis and for in-line or in vivo analyses. Temperature gradients at hot microelectrodes may exceed 1.5 x 10(5) K/cm, which makes them useful in studies of Soret diffusion and thermoelectric phenomena.

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confidence: 99%

Hot Microelectrodes

Barański

2002

Anal. Chem.

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“…Temperatures beyond the boiling point are possible since the bubble formation associated with the boiling process is kinetically delayed. Even higher temperatures should be possible, as temperatures up to 250 °C were reported [25]. We also studied the temperatures reached with shorter heat pulses of 1, 5, 10, and 50 ms duration.…”

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confidence: 99%

Development of a Temperature‐pulse Enhanced Electrochemical Glucose Biosensor and Characterization of its Stability via Scanning Electrochemical Microscopy

et al. 2021

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Glucose oxidase (GOx) is an enzyme frequently used in glucose biosensors. As increased temperatures can enhance the performance of electrochemical sensors, we investigated the impact of temperature pulses on GOx that was drop-coated on flattened Pt microwires. The wires were heated by an alternating current. The sensitivity towards glucose and the temperature stability of GOx was investigated by amperometry. An up to 22fold increase of sensitivity was observed. Spatially resolved enzyme activity changes were investigated via scanning electrochemical microscopy. The application of short (< 100 ms) heat pulses was associated with less thermal inactivation of the immobilized GOx than longterm heating.

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“…They found that supercritical conditions could not be achieved by fast pulse heating due to rapid pressure decrease. Maximal 250 °C could be reached in case of 5 ms heat pulses 82,83. Recently, Gründler reported on a new implementation of his technique 84.…”

Section: Temperature Pulse Methodsmentioning

confidence: 99%

Electrically Heated Electrodes: Practical Aspects and New Developments

Flechsig¹,

Walter²

2011

Electroanalysis

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This article comprehensively reviews a selected subfield of thermoelectrochemistry, which bases upon joule-heated working electrodes. Both directly and indirectly heated electrodes are considered. In all cases, an electric current (AC or DC) is used to elevate the electrode temperature during the electrochemical processes. The development of joule-heated electrodes started as early as 1966 and was greatly accelerated by Gründler et al. since 1993. However, during the last 5 years the development became even faster, when other groups started to contribute novel approaches and designs on how to implement electrically heated electrodes in capillary electrophoreses and spectroelectrochemistry. To date there are more than 90 publications on heated electrodes.

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The Limits of Aqueous Hot-Wire Electrochemistry: Near-Critical and Supercritical Fluids in Electrochemical Sensors?

Cited by 24 publications

References 10 publications

Hot Microelectrodes

Hot Microelectrodes

Development of a Temperature‐pulse Enhanced Electrochemical Glucose Biosensor and Characterization of its Stability via Scanning Electrochemical Microscopy

Electrically Heated Electrodes: Practical Aspects and New Developments

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