Microelectrode general properties
Adamant Technologies’ experience in micro-structuring and coating depositions are exploited in the design and manufacturing of sensors based on microdisc array silicon chips.
Due to the specific features of microelectrodes, sensors using them provide unique solutions to many situations. The most remarkable properties of microelectrodes are described bellow.
The hemispherical diffusion profile induces an improved mass transfer compared to that of macro-electrodes. This brings much higher current density, which translates into a high signal to noise ratio. Furthermore, the limiting current is reached quickly.
Microelectrodes allow working in very high resistive media without loss of sensitivity. This is due to the small currents and to the facts that the ohmic drop is limited to a small area close to the electrode.
The sensing is done within the diffusion layer and this induces a very low dependence on hydrodynamic conditions. With such microelectrodes, the smaller microelectrode diameters are, the lower the flow dependence is. As example, diameters of 2 to 15 µm lead to almost complete flow independence.
A further advantage, specifically relevant to effective on-line operation at elevated and varying pressures, is that microelectrodes do not necessarily require a membrane in order to attain selectivity and reduced fouling in relation with the right measuring protocol.
Microelectrode arrays retain the already mentioned attractive properties of single microelectrodes while enhancing the sensor response by more than two orders of magnitude.
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