Scattering Light Noise Research on Laser-Induced Fluorescence detection for capillary electrophoresis

Capillary electrophoresis and microchip capillary electrophoresis based on laser induced fluorescence detection (CE-LIFD) played an important role in biology and analytical chemistry for separation and quantitative research of biological samples. This paper presented an analysis on the noise of LIF detection brought by scattering from polymer used as sieving matrix. The theory of laser scattering by polymer was provided. An experiment system was established with excitation laser of 488 nm. Noise data of LIF detection for the electrophoresis of a capillary manufactured in a microchip with 1% linear poly- acrylamide coated on the internal wall was assessed, which had an effective internal diameter of 50 mum. Conclusion was made that noise data increased with the improvement of applied electric field strength. The possible cause was provided and analyzed, too.