Abstract

Capillary electrophoresis (CE) is a rapid and efficient separation technique for small volume samples, which has attracted much attention. Combined with laser induced fluorescence (LIF) detection, extraordinary sensitivity can be achieved. Lasers, emitting light in the visible as well and in the UV have been used in recent studies to detect biomolecules, e.g., amino acids, DNA¹ or proteins². Compared to classical electrophoresis, CE offers better possibilities for automated analysis where a compact and reliable detection unit is necessary. An all solid state laser for LIF would be the ideal light source. Compared to gas lasers, which have been employed, the solid state laser is more compact, stable and has a lower power consumption. Moreover, the reliability and the minimum maintenance requirement of a solid state laser would be an important advantage³. Frequency doubled diode lasers using quasi-phase matching (QPM) waveguides are interesting candidates as light sources for LIF, as the output wavelength could be chosen to match the absorption band of the fluorescing analyte. Also, sufficient power (in the order of mW) in the blue light region could be generated⁴.

© 1993 Optical Society of America