Electrode polarization is a significant obstacle in the impedance measurements of ionic liquids. An atomically smooth electrode surface could potentially reduce unwanted impedance contributions from electrode polarization. Liquid metal electrodes were formed by adhering Galinstan to acrylic plates in a parallel-plate capacitor arrangement. Electrode polarization was compared to a similar cell with stainless steel electrodes. The impedance of salt and protein solutions (β-lactoglobulin) was measured from 40 Hz to 110 MHz. Because of oxide layer formation, the performance of the Galinstan electrode is significantly different than the theoretical ideal.

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Dielectric spectroscopy is used to probe the electrical properties of biomolecules dissolved in liquids. A 40 μl cell is constructed out of acrylic with polished, stainless steel electrodes. Experiments are performed on avidin and biotin-labeled BSA, showing characteristics of aggregation. Experiments with avidin and biotin demonstrate shifts in dielectric relaxation of the avidin associated with changes in the dipole moment and size of the molecule due to biotin binding. These shifts are analyzed in the context of biomolecular changes. These experiments demonstrate the utility of impedance spectroscopy to detect changes due to small molecules binding to proteins.