Lab-on-chip FIA system without an external pump and valves and integrated with an in line electrochemical detector

摘要

Surface energy in small droplets can be used to drive samples through micro-channels. When a sample fluid is spontaneously driven through a solution filled micro-channel with liquid droplets on its entry (sample) and exit (reservoir) ports it is termed as a passive pumping device. A passive pump driven micro-fluidic system integrated with microfabricated planar electrodes or electrode arrays (e.g., interdigitated electrode arrays, or microband electrode arrays) can be considered as a manifold for flow injection analysis without external pump and injector valve. Factors affecting the passive pump driven flow rate in a polydimethylsiloxane (PDMS) – glass hybrid micro-fluidic system, including the volume, viscosity and surface tension of the sample solution and the tilt of the microfluidic channel are analyzed. By placing 2 μL hexacyanoferrate (II) solutions at the entry port of the device peak shaped transients were recorded. The peak heights showed linear dependence on the sample concentrations between 3·10⁻⁷ and 10⁻⁵ M.