LAB-ON-A-CHIP ANALYSIS WITH CACITIVELY COUPLED CONTACTLESS CONDUCTIVITY DETECTION (C4D)

Abstract

Contactless Coupled Conductivity Detection (C4D) is a universal detection technique for charged molecules and especially practical for the direct detection of inorganic and organic ions that are not able to be detected by other means without labeling process. In this thesis report, C4D is used in conjunction with electrophoresis in a microfuidic device to separate and quantify inorganic ions in water. Comprehensive simulations are carried out to model the detection system and optimize the detector sensitivity. The fluidic channel geometry, specifically the cross section area of the detection cell is narrowed to increase the cell resistance and improve the current coupling. Nanofabrication has been employed to fabricate the nano micro channel in polymeric substrates. A novel design which successfully reduced the cross section area of fluidic channel is fabricated and tested. The result shows the detection sensitivity has been improved approximately 6 times over the conventional fluidic channel.