Direct observation of sample trapping process onto internal-surface reversed-phase pre-column

The solute trapping procedure onto a bovine serum albumin (BSA)-coated ODS pre-column was directly observed with a chromato-videoscope. The fluorescence image of dansyl (DNS) amino acids along the column was detected by a video camera and the images were digitized and analyzed as densitograms by an image processor. DNS-amino acids were retained at the top of pre-column and formed a distinctive band when phosphate-buffered saline (PBS) was used as a mobile phase. However, the shape of the solute bands was affected by the presence of BSA in the sample solution and also by the flow rate.