On-chip preconcentration and separation of simple and complex analytes using isotachophoresis

We present a theoretical model and parametric study of isotachophoresis based preconcentration of trace analytes in microfluidic devices. We use a simple semi-analytical model to capture the self-sharpening effect of isotachophoretic boundaries and solve the unsteady problem of fluorescent analytes preconcentration inside these boundaries. We evaluate the influence of various experimental conditions to achieve rapid preconcentration of these simple analytes. We also experimentally demonstrate the non-ideal complexities exhibited by biological samples such as proteins and DNA. These higher molecular weight species, due to additional steric hindrance and wall interactions, exhibit more complicated electromigration behavior and preconcentration.