Red diode laser induced fluorescence detection with a confocal microscope on a microchip for capillary electrophoresis


  1. Jiang, G.
  2. Attiya, S.
  3. Ocvirk, G.
  4. Lee, W.E.
  5. Harrison, D.J.
Corporate Authors
Defence Research Establishment Suffield, Ralston ALTA (CAN)
A highly sensitive laser induced fluorescence (LIF) detection system based on a 635 nm laser diode and cyanine-5 (Cy-5) dye, is described for use with a planar, microfluidic, capillary electrophoresis (CE) chip. The CE-chip is able to determine a protein biological threat agent simulant, ovalbumin (Ov), by performing an immunuoassay separation of Cy-5 labeled anti-ovalbumin from its complex with Ov, in under 30 s. A confocal, epiluminescent detection system utilizing a photomultiplier tube gave optimum results with a 400 Mum pinhole, an Omega 682DF22 emission filter, a 645DRLP02 dichroic mirror, a 634 + or - 5 nm excitation filter, and a Power Technology ACM08 635 nm laser operated at 11.2 mW. Using this detector, a microchip CE device with a separation efficiency of 42000 plates and an etch depth of 20 Mum, gave a concentration detection limit of 9 pM Cy-5. This limit corresponds to the determination of 4560 injected molecules and detection of 900 of these molecules, given a probe volume of 1.6 pl and probing efficiency of 20%.
Affinity capillary electrophoresis;Bioanalysis;Capillary Electrophoresis (CE);Capillary zone electrophoresis;Immunoassay separations;Laser Induced Fluorescence (LIF);Microchip;Microfluidics;Ovalbumin
Report Number
DRES-SL-1999-085 — Paper
Date of publication
21 Dec 2000
Number of Pages
Hardcopy;Document Image stored on Optical Disk

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