Insulin, proinsulin, and c-peptide on-line, pre-column automatic derivatization and separation were demonstrated by using the microSI-LOV system, coupled with capillary electrophoresis (CE) The SI-LOV system serves as the sample pretreatment “front-end” for CE, allowing programmable sample derivatization and injection. Fluorescence response was collected by an epiluminescence fluorescence microscope. Reaction conditions were optimized by selecting different stop- and inject positions of the sequenced sample-reagent profile by programming the stop flow position of reacted zone at the capillary inlet. Surface of the CE capillary was automatically regenerated after 10 to 15 sample separations. The sampling frequency was increased by hydrodynamically flushing the unwanted, unprocessed sample residue still in the capillary after the monitoring of the desired sample peak was completed. For the electrochromatogram on the right, 5.15 mM bovine insulin, 1.96 pM proinsulin, and 781.1 nM c-peptide standard solutions were derivatized with fluorescamine reagent individually for 10 seconds in the LOV module, followed by electrokinetic (EK) injection and separation in the CE capillary.
Insulin by CE
2.4.15.
