Terahertz-capillary electrophoresis (THz-CE) for direct detection of separated substances in solutions

Abstract

We present a novel technique for capillary electrophoresis (CE) using terahertz (THz) waves, namely “THz-CE,” which enables us to sensitively detect separated substances in a solution flowing in a hollow of capillary whose inner diameter is smaller than 100 µm. Such THz detection could be achieved by utilizing the near-field interaction between a solution filled in a capillary and a point THz source that was locally generated by optical rectification in a nonlinear optical crystal irradiated with a femtosecond pulse laser. Here, we investigated the performance of THz-CE numerically and experimentally, and succeeded in observing the electrophoretic chromatogram for the separation between acetic acid and n-propionic acid by THz-CE.