Application of external micro-spectrophotometric detection to improve sensitivity on microchips
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The goal of this work was to increase the sensitivity of a UV–Vis spectrophotometer by decreasing the background noise and lengthening the optical path. A microphotometer has been modified to precisely select very small parts of a microfluidic channel pattern of a chip and to measure light absorbance on a magnified area of the selected part of the channel. The viability of combining a projection microscope and a spectrophotometer for external absorbance measurements on disposable PDMS chips was studied. Besides the external direct detection above a microfluidic channel, the optical pathlength was lengthened by detecting in the region of the perpendicular exit port. Increasing the cross-sectional area of the zone of irradiation improved the signal-to-noise ratio and the limits of detection (LOD).
KeywordsChip Poly(dimethylsiloxane) External UV detection Micro-spectrophotometer Flow injection Microfluidics/microfabrication UV/Vis
The authors gratefully acknowledge financial support for this research by grants from the National Scientific Research Fund, Hungary K75286), the National Office for Research and Technology (Baross-2-2007-0028) and the National Science Foundation (DMR-0351848, CHE-0515363, and OISE-0754138).
- 1.Tabeling P (2005) In introduction to microfluidics. Oxford University PressGoogle Scholar