Postcolumn Derivatization
Post column derivatization requires a continuous supply of reagent, and therefore it necessitates the use of a second, low pressure pump connected by means of a confluence point after the column and in front of the detector.

Post-column derivatization following separation on a monolithic column has been published recently (Adcock 2007). The authors designed an instrument based on a flow injection scheme, served with three Milligat pumps. A pair of pumps upstream from the injection valve created an elution gradient, while the third pump supplied a derivatization reagent in postcolumn fashion. This innovative work allowed excellent separation of opiate alkaloids and biogenic amines for their assay in urine, using chemiluminiscence detection.

Adcock J.L., Francis P.S., Agg K.M., Marshall G.D., Barnett N.W.: Anal. Chim. Acta 600 (2007) 136-141.