Formation of a water-xylene interface in a microchannel without sidewalls

Channels in a microfluidic device were rapidly created using an office inkjet printer. The process was easy enough for common end users to carry it out by themselves. A water-xylene interface was formed by combining two parallel channels that were filled with water and xylene, respectively. Such an interface can be important in analytical and synthetic uses because various chemical processes, such as reaction, extraction, and separation, can be performed through the interface. The water-filled channel was 0.5-1.3 mm wide, and the xylene-filled one was 1.3 mm wide. Both channels were 0.09 mm deep and 20 mm long. The continuous flow of these fluids was successfully carried out using a syringe pump at a volume flow rate of 1 microL/min for 5 min.