A simple subatmospheric pressure device to drive reagents through microchannels for solution-phase synthesis in a parallel fashion

A simple but effective subatmospheric pressure device has been developed to drive reagents through microfluidic channels for solution-phase parallel synthesis. Y-shaped microfluidic glass chips with different channel lengths were fabricated using a photolithographic and wet chemical etching procedure. The subatmospheric pressure device, composed of a microvacuum pump, a buffer vessel and a vacuum gauge with two electric switches, can automatically adjust the applied vacuum range in the buffer vessel as required. With the subatmospheric pressure as the driving force, the fluid flow in parallel channels can be precisely controlled, respectively, by the needle valves and monitored by a water filled U-tube manometer. The system was evaluated with Suzuki coupling reaction in a parallel fashion as a demonstration. Experimental results confirmed that the developed system is superior for parallel synthesis parameter evaluation.