Capillary electrophoresis with laser-induced fluorescence in clinical drug development: Routine application and future aspects

The clinical bioanalytical setting is characterized by sample volumes of <1 ml biological fluid (e.g. plasma, urine), a range of 3–4 decades of concentrations to be quantified and a limit of quantitation in the μg/l–ng/l range for sets of 100–5000 individual samples. Setup of capillary electrophoresis (CE) for routine application in this analytical field was successful for analytes accessible to fluorescence detection by using laser-induced fluorescence (LIF) detection. Empowerment of CE–LIF for routine serial analysis of thousands of samples includes improvement in autosampler techniques, thorough procedures for capillary treatment and particularly more advanced detection technology. Introduction of multi-capillary systems with charge-coupled device cameras and frequency doubled Ar-ion laser (λ=257 nm) offers this technique the chance of superiority over classical analytical assays — especially in the field of (new) low volume samples e.g. capillary blood or microdialysate encouraging clinicians to search for meaningful non-invasive samples.