Development Of Analytical Method For Inorganic Ions Based On Microfluidic Devices

Microfluidic systems have attracted considerable attention and have been widelyapplied in the fields of analytical, environmental, medical and biological monitoringet al. due to advantages associated with miniaturization, integration, and automation.The aims of this article are to design and manufacture an integrated microfluidic chipsystem, based on the platform of chip and the traditional methods, to develop aminiaturized and portable device for the analysis of inorganic ions. The key problemto address is about the integration of the chip, which will make the device small andsimple for the field analysis.Firstly, there is a brief introduction on the background, development andapplication of the microfluidic technique, as well as the materials and procedures formicrochip fabrication. Meanwhile a review of recent progress in miniaturization andintegration of chip was made, especially in parts of sample pretreatment and detectiontechniques. Secondly, a PDMS-glass chip was designed and fabricated, meanwhilesome conditions in manufacturing were investigated. Thirdly, for the purpose ofsample purification and preconcentration on-chip, a concentrator was developed inchannel of the chip. By designing weirs in the microchannel to confine the cationicsolid phase particles, a microscale solid phase extraction device was fabricated andused for metal ions concentration. In combination with post-column derivatization,the concentrated metals were mixed and complexed with HQS on line, then detectedwith the sensitive laser induced fluorescence method on-chip. Four metal ions wereused to evaluate the device. The results showed an efficient concentrated factor about500, and a better reproducibility with RSD <4%, n=7. Fourth, a lab-on-a-chip (LOC)system integrated with LED-induced fluorescence detection was set up, by integratinga small size and low cost LED as well as a minaturized filter into the PDMS chip. Inthe presence of Na2SO3as reducer and OPA as complexing reagent, NH4+was mixedand reacted with these reagents on-chip, then was selectively and sensitively detected.The research realized the integration and minaturization of the device, whichdecreased the cost and simplified the analytical procedure. Finally, a conclusion forthe work was summarized, as well as a brief outlook on the application of microchipin various fields.