Study of orthogonal vector lock-in amplifier in contactless conductivity detector of electrophoresis microchip

An output signal detection method of the contactless conductivity detector of electrophoresis microchip based on orthogonal vector lock-in amplifier is presented. The parameters, which include the excitation signal frequency, the amplitude and frequency of a measured signal, influences on the separation chromatogram detection of electrophoresis microchip is emphatically discussed. The simulation results show that the orthogonal vector lock-in amplifier has superior signal detection capability for on-plane four-electrode contactless conductivity detector, and it can effectively achieve microchips electrophoresis signal detection and pick-up.