Abstract
This paper presents a new microfluidic device capable of precise sampling and variable-volume pipetting. The pneumatic valves were designed to control the volumes of the dispensation channel with specific ratios such as 1x, 5x and 30x. By means of proper combinations of the ratios, variable-volume liquid can be easily dispensed with a volume ranging from 1x to 100x. This microdevice made of polydimethylsiloxane (PDMS) using soft lithography techniques can be easily integrated with other microfluidic devices for further micro-total-analysis-system applications.