“Getting the best sensitivity from on-capillary fluorescence detection in capillary electrophoresis” – A tutorial

•Comprehensive tutorial of sensitive fluorescence detection with capillary electrophoresis.•Critical theoretical and experimental milestones during optimization of detection efficiency.•Graphical artworks and helpful mathematical formulas to encourage implementation of the tutorial's aim.•Promising approaches to improvement of sensitivity in capillary electrophoresis techniques with fluorescence detection.

Capillary electrophoresis with Laser-Induced Fluorescence (CE-LIF) detection is being applied to new analytical problems which challenge both the power of CE separation and the sensitivity of LIF detection. On-capillary LIF detection is much more practical than post-capillary detection in a sheath-flow cell. Therefore, commercial CE instruments utilize solely on-capillary CE-LIF detection with a Limit of Detection (LOD) in the nM range, while there are multiple applications of CE-LIF that require pM or lower LODs. This tutorial analyzes all aspects of on-capillary LIF detection in CE in an attempt to identify means for improving LOD of CE-LIF with on-capillary detection. We consider principles of signal enhancement and noise reduction, as well as relevant areas of fluorophore photochemistry and fluorescent microscopy.

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