Adapting the Laser-Induced Fluorescence Detection Setup of the Standard Capillary Electrophoresis Equipment to Achieve High-Sensitivity Detection of 2-Aminoacridone Labeled Oligosaccharides.

The high-sensitivity capabilities of laser-induced fluorescence (LIF) detection continuously promote the development of various labels with different fluorescence properties. However, this strategy also requires the adaptation of existing detection systems to suit the excitation and emission characteristics of novel fluorescent tags. In this study, we adapted the LIF detector of the commercial capillary electrophoresis instrument to the specific fluorescence spectra of 2-aminoacridone labeled human milk oligosaccharides. An external solid-state laser with a wavelength of 405 nm was connected to the commercial capillary electrophoresis instrument via a simple 3D-printed laser-to-light-guide adapter, and different optical filter setups were compared based on the signal-to-noise ratio. The optimized setup provided detection limits as low as 0.27 to 0.34 nM, corresponding to injection of 3.4 to 4.6 attomoles of 2-aminoacridone labeled oligosaccharides. These findings show that the optimized laser and filter configuration can enhance the sensitivity of electrophoretic separation by several orders of magnitude. In addition, the presented setup can be utilized as a guide for coupling different lasers to the commercial instrument.