Application of external micro-spectrophotometric detection to improve sensitivity on microchips.
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).
Gáspár
Attila
A
Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary. gaspara@tigris.unideb.hu
Bácsi
István
I
Garcia
Erika F
EF
Braun
Mihály
M
Gomez
Frank A
FA