微小ガラス電極を用いた局所電場計測による導電率の評価

抄録

Recently, developments of micro- and nanofluidic devices have attracted much attention. Electrical sensing of single nanoparticles using micro- and nanofluidic channels is one of the most featured technologies. However, details in ionic current responses induced by nanoparticle transport phenomena have not yet been understood because there is not a useful method to measure local conditions in liquids. Especially, local electric fields and concentrations far from the electrode surfaces in liquids are required to be clarified. Herein, we have developed a glass microelectrode that has a small tip less than 1 μm in diameter and that enables us to measure electric potential distributions in electrolyte solutions. Sequencing the glass microelectrode along a fluidic channel that has an orifice of the sensing portion, electric potential differences is locally measured with a spatial resolution comparable with the glass tip size. It is also found that an electric field almost uniform is formed at the orifice, where concentrations are uniform and current-voltage characteristics obeys Ohm’s law.