We report an online, optical injection interface for capillary zone electrophoresis (CZE) based upon photophysical activation of a caged, fluorogenic label covalently attached to the target analyte. This injection interface allows online analysis of biomolecular systems with high temporal resolution and high sensitivity. Samples are injected onto the separation capillary by photolysis of a caged-fluorescein label using the 351-364 nm irradiation of an Ar+ laser. Following injection, the sample is separated and detected via laser-induced fluorescence detection at 488 nm. Detection limits for online analysis of arginine, glutamic acid, and aspartic acid were less than 1 nM with separation times less than 5 s and separation efficiencies exceeding 1 000 000 plates/m. Rapid injection of proteins was demonstrated with migration times less than 500 ms and 0.5 nM detection limits. Online monitoring was performed with response times less than 20 s, suggesting the feasibility of this approach for online, in vivo analysis for a range of biologically relevant analytes.
ASJC Scopus subject areas
- Analytical Chemistry