Originally, HPLC methods were developed using a 4.6 mm ID columns and greater. At the time, the separations were acceptable and not much emphasis was placed on either reducing solvent consumption or increasing sensitivity. Eventually, 3.0 mm ID columns were introduced as a means of reducing solvent consumption and offered increased sensitivity when the same sample mass was used. Furthermore, 2.1 mm ID columns arrived for use with UHPLC and for interfacing to mass spectrometers. As UHPLC column technology and instrumentation has progressed, the move to smaller ID columns has proven to be advantageous.
Author: Dr. Stephanie Schuster, Senior Technical Support Scientist, Advanced Materials Technology