Investigation of field-amplified sample stacking in microchannels

Herein, concentration enrichment of sample solutes is obtained by using field-amplified sample stacking (FASS) in microchannel. Numerical investigations are performed to explored the effects of different parameters including the applied voltage, the charged properties of the sample, the buffer concentration ratio, and the injection length on the enrichment performance, and to study the influence of Joule heating effect on FASS. Furthermore, a high conductance gradient boundary is established by photoinitiating fabrication of a porous plug at the enriched interface position. Experimental results show that the fluorescein-Na with 0.1 μM initial concentrations achieves a 329-fold enrichment.