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Improving signal to background ratio for on‐the‐fly fluorescence lifetime detection in capillary electrophoresis
Author(s) -
Li Liangchi,
McGown Linda B.
Publication year - 2000
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(20000401)21:7<1300::aid-elps1300>3.0.co;2-n
Subject(s) - capillary electrophoresis , signal (programming language) , microscope , fluorescence , materials science , confocal , capillary action , laser induced fluorescence , optics , laser , lens (geology) , fluorescence spectroscopy , analytical chemistry (journal) , chemistry , chromatography , computer science , physics , composite material , programming language
On‐the‐fly fluorescence lifetime detection (OFLD) in capillary electrophoresis (CE) was previously demonstrated using a commercial multiharmonic Fourier transform (MHF) spectrofluorometer interfaced to a commercial CE system. This paper discusses optimization of the interface design for minimization of background fluorescence and scattered light, thereby maximizing the signal‐to‐background ratio (S/B) of the dynamic measurement. Strategies included using various combinations of optical filters including a holographic filter and longpass or bandpass filters, tilting the capillary relative to the incident laser beam, employing a confocal design and adding an iris to remove out‐of‐focus light, using a microscope objective in the emission beam to increase the collection efficiency, and using square instead of ciruclar capillary columns. Significant improvements in S/B for on‐column, on‐the‐fly detection of fluorescein in CE were achieved with most modifications.