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Autori: Danut-Ionel Vaireanu, Peter R. fielden, and Bernard J Treves Brown
Editorial: ISSN 0957-0233, Institute of Physics Publishing Ltd, Measurement Science and Technology, 11, p.244-251, 2000.
A conductivity detector providing high voltage isolation for
electroseparations is described. It is based on an oscillator which is
capacitively coupled to the measurement electrodes; the conductance
between the electrodes determines the output frequency. The detector was
evaluated using a small-volume (500 nl) conductivity cell (cell constant
5.1´10-3 m-1) cell which is described; it was then characterized using a
factorial method and optimized to maximize the sensitivity (absolute
change in frequency) to changes in conductivity.
A novel method was used to determine the cell constant for a pair of
microband electrodes (100 µm across on 200 µm centres) with electrolyte
confined in a fine channel above them — this was 2615 ± 86 m-1 and the
detector has been used with this cell for isotachophoretic separations
Cuvinte cheie: conductivitate, constanta celulei, detector, isotacoforeza // conductivity, cell constant, detector, isotachophoresis