Analytical and Bioanalytical Chemistry

, Volume 373, Issue 7, pp 519–525

On-chip absorption measurements using an integrated waveguide

  • Bryan G. Splawn
  • Fred E. Lytle
Special Issue Paper

DOI: 10.1007/s00216-002-1316-9

Cite this article as:
Splawn, B.G. & Lytle, F.E. Anal Bioanal Chem (2002) 373: 519. doi:10.1007/s00216-002-1316-9


Square hollow waveguides are used to integrate measurement of absorption with chip-based electrophoresis. The 50×50 µm liquid channel and 50×50 µm waveguide are etched as a negative pattern into a silicon master and replicated as a positive in poly-dimethylsiloxane (PDMS). The uniform refractive index of the chip prevents guiding by total internal reflection. Instead, light at 488 nm is guided by reflection at the air-PDMS interface. The waveguide has a 60% efficiency over a distance of 3.2 cm. Separation of fluorescein and the dye BODIPY is demonstrated. A detection limit (S/N=3) of 200 µM fluorescein is obtained using a 50 µm pathlength and a simple photocell detector.

Waveguides Absorption detection Capillary electrophoresis Poly-dimethylsiloxane Chip

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Bryan G. Splawn
    • 1
  • Fred E. Lytle
    • 1
  1. 1.Chemistry Department, 1393 Brown Laboratories, Purdue University, West Lafayette, Indiana 47907-1393USA