Electrode location impact on cole-impedance parameters using magnitude-only measurements

Abstract

In this paper the variability of the Cole-impedance parameters, extracted from magnitude-only measurements using a two-electrode setup are examined. Eight electrodes placed around the centre latitudinal line of an apple are used to collect magnitude measurements from 200 Hz to 1 MHz. Parameters are extracted in MATLAB using a non-linear least squares fitting (NLSF) algorithm, with simulations showing less than 0.5% average relative error compared to the experimental data. The variability, based on electrode location, of each parameter and select combinations are calculated and discussed; with R ₁ and R ₀ showing the highest variability and α the lowest in this setup. The combinations R ₁ /R ₀ and τ = (R ₁ C) ^1/α show lower variability than R ₁ , R ₀ , and C, making them potentially more attractive for monitoring physiological changes than the the individual parameters.