Modular instrumentation for capillary electrophoresis with laser induced fluorescence detection using plug-and-play microfluidic, electrophoretic and optic modules.

This study reports on the development of a novel instrument for capillary electrophoresis (CE) coupled with laser induced fluorescence (LIF) detection that is inspired by the Lego-toy concept. The Lego CE-LIF design is an evolution of purpose-made CE instrumentation, allowing the users to construct their own analytical device with a high degree of standardization (i.e. a "standard" setup) without requirement of mechanical and electronic workshop facilities. To allow instrument reproduction outside the original fabrication laboratory, which is not trivial for in-house-built CE systems, the new design is based on unprecedent 'plugging' hyphenation of various off-the-shelf parts available for microfluidics, optics and electrophoresis. To render the operation with Lego CE-LIF optimal, we developed a new background electrolyte (BGE), using for the first time extremely high concentrations of zwitterionic and large weakly charged species for much improvement of detection sensitivity. The Lego CE-LIF was demonstrated for separation and detection of oligosaccharides labelled with 8-aminopyrene-1,3,6-trisulfonic acid (APTS). The new gel-free BGE for oligosaccharide analysis also allowed simplification of the conventional CE-LIF protocol used with commercial instruments while keeping satisfactory separation performances. Furthermore, the new BGE is fully compatible with a non-thermostatted Lego CE instrument thanks to low current and therefore low heat generation under application of a high voltage.