科研之友
微信
新浪微博
Facebook
分享链接
摘要
A high-pressure electro-osmotic micro-pump fabricated by a sol-gel process is reported as a fluid-driving unit in a flow-injection analysis (FIA) system. The micro FIA system consists of a monolithic micro-pump on a glass slide (2.5 x 7.5 cm), a micro-injector, and a microsensor ( 2.5 x 1.5 cm). The monolithic silica matrix has a continuous skeleton morphology with micrometer-sized through-pores. The micrometer-size pores with a large negative surface charge density build up a large pressure under a DC electric field to drive fluid through the downstream units. A novel Nafion joint for the downstream cathode eliminates flow into the electrode reservoir and further enhances pressure build-up. The measured pump-pressure curve indicated a maximum pressure of 0.4 MPa at. ow rate of 0.4 μ L min(-1) at 6 kV. Despite the large voltage, the small current transmission area through the monolith produced a negligible current ( less than 100 μ A) that did not generate bubbles or ion contaminants. The. ow rate can be precisely controlled in the range 200 nL to 2.5 μ L min(-1) by varying the voltage from 1 to 6 kV. The high pump pressure and the large current-free DC field also enabled the pump to act as an electro- spray interface with a downstream analytical instrument.
- 出版日期2005-6
