Development of a capillary electrophoresis-77 K luminescence detection system for online spectral identification

We have demonstrated that capillary electrophoresis (CE) can be easily inte rfaced with 77 K luminescence spectroscopy (LS) for separation and online s pectral identification of structurally similar analytes. This novel CE-LS a pparatus consists of a regular CE system, instrumentation for LS and a spec ially designed capillary Dewar. When the separating molecules traverse into the cryostat detection window, liquid nitrogen is added, freezing the sepa rating analyte zones within the capillary. At low temperature, detection li mits are improved via signal averaging and the inherent increase in quantum yield at 77 K. We present the first application of the CE-LS system to str uctural isomers (2,3- and 3,4-methylenedioxymethamphetamine) and stereoisom ers (trans- and cis-resveratrol). With this approach, the CE-LS interfacing provides a sensitive, accurate, rapid, simple and economic methodology for analytical chemistry.