Dispensing and Diagnostics of Nano-liter Samples in Microreactors Using Electroosmotic Flow

by Arumbuliyur Comandur, Kaushik

Abstract (Summary)
This study describes a microreactor design in which two samples are injected simultaneously, using electroosmotic flow and mixed in the microreactor. Both numerical and experimental investigations were carried to evaluate the pinching, switching and mixing of nanoliter sample volumes in the microreactor. The microreactor was fabricated on PDMS/glass hybrid and tested using fluorescein spectroscopy. The first step in this study was the pinch precise sample volumes are the center of microchannels. This was achieved by applying suitable voltages at the reservoirs. Different pinching conditions namely strong, medium and weak were obtained by controlling the voltages. The next step after pinching was to inject the samples to the microreactor. The timing of the sample injection was also controlled by changing the applied electric fields. In order to optimize the injection process effects of sample size and applied electric field on sample concentration were studied. It was found that the normalized final concentration of the sample increased from 0.03 to 0.11 as the sample length increased from 60 to 150 ?m at constant electric field. Also, there was a decrease in the final concentration at the microreactor as the electric field strength increased. The concentration decreased from 0.14 at 100 V/cm to 0.04 at 1000 V/cm. The final study involved mixing the samples and modeling the reaction between the samples. The samples were allowed to mix in the microreactor for a period of 4.5 s. It is seen that normalized concentration of the product increases from 0.25 to 0.45 during that period.
Bibliographical Information:


School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:electroosmotic flow pinching switching microreactor reactions


Date of Publication:01/01/2009

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