IN-COLUMN VERSUS ON-COLUMN PHOTOMETRIC DETECTION IN CAPILLARY ELECTROCHROMATOGRAPHY WITH CAPILLARIES PACKED WITH OCTADECYLSILICA GEL

With capillary electrochromatography (CEC) performed with capillaries packed with octadecylsilica gel, photometric detection (in the visible and in the ultraviolet regions) is possible in a packed section (in-c olumn detection) or an emptied section (on-column detection) of the se paration capillary. The influence of the detection mode on linearity o f the calibration function, precision, and detection limit is investig ated. It is shown that the signal enhancement due to enrichment of sol ute in the stationary phase can be quantitatively described with an eq uation derived elsewhere for in-column fluorescence detection. (C) 199 8 John Wiley & Sons, Inc.