Surface-enhanced Raman scattering: A structure specific detection method for capillary electrophoresis

A new approach to detecting capillary electrophoresis (CE) eluent component s by interfacing CE with a surface-enhanced Raman scattering (SERS) system is described. In this approach, CE-based separation of a mixture of trans-1 ,2-bis(4-pyridyl)ethylene and N,N-dimethyl-4-nitrosoaniline has been detect ed by SERS in a postcolumn Geometry. The retention time obtained from SERS corresponds well with that from conventional UV-visible detection. Meanwhil e, CE eluants are identified by their characteristic vibrational spectra, d emonstrating the validity of SERS as a structure-specific detection method for CE. In addition, the ability to monitor SERS intensity changes at molec ule-specific frequencies makes selective detection of individual analytes p ossible, even when separation is incomplete. Finally, CE-SERS is evaluated for separation of amino acids (tyrosine and tryptophan) and environmental p ollutants (chlorophenol mixtures).