Effect of AC voltage frequency on the sensitivity of conductometric detection in microseparation techniques

Conductometric detectors employed in microseparation methods are designed t o primarily match the separation criteria. Consequently, their geometry is seldom optimal from the point of view of conductometry. An unsuitable detec tion cell geometry is manifested in the dependence of the conductometric ce ll constant on the frequency of the AC signal applied to the electrodes. Va riations in the cell constant value cause changes in the measured signal ev en if the solution conductivity is constant. By varying the frequency of th e AC signal it is thus possible to find an optimal frequency at which the h ighest detection sensitivity is attained. The optimum frequency depends bot h on the cell geometry and on the conductivity of the mobile phase solution . (C) 1999 Elsevier Science B.V. All rights reserved.