Flow-type chemiluminescence detection cell using an optical fiber for capillary electrophoresis

A flow-type chemiluminescence detection cell using optical fiber was design ed for capillary electrophoresis. The capillary was set up straight to the optical fiber with a certain distance in a Teflon(R) tube. Hydrogen peroxid e was delivered through a three-way joint by a syringe pump and mixed with analytes at the capillary outlet. Luminol chemiluminescence was adapted for use with this detection cell. Analytical conditions, such as hydrogen pero xide flow rate, distance between the capillary and the fiber, and the reage nt concentrations, were examined in detail with the cell. The present flow- type system provided a CL signal with high sensitivity, resolution, and rep roducibility. The detection limit (S/N = 3) for luminol was 7.6 x 10(-9) M (28 amol; 3.7 nl injected) with theoretical plate numbers of 130000-160000 and a relative standard deviation of 3.3 % for the peak height (n = 10). A mixture sample of glycine, glycylglycine, and glycylglycylglycine, which we re labeled with isoluminol isothiocyanate (2,3-dihydro-6-isothiocyanato-1,4 -phthalazinedione), was also subjected to the present system. They were sen sitively detected and represented with high resolution.