Automatic Column Coupling System To Operate Chromatographic Supports Closer To Their Kinetic Performance Limit and To Enhance Method Development

摘要

A new hardware solution is proposed that allows one tonautomatically change the length of a chromatographic bed.nThe setup is based on the serial coupling of chromatographicncolumns using two rotor-stator valves (with Nnpositions, N + 1 ports). Despite the use of a prototypensetup requiring rather long connection tubing, only 9%nloss in efficiency is observed for compounds with anretention factor above 4 compared to the efficiencynexpected on the basis of the individual column results. Itnhas been demonstrated for a number of isocratic andngradient separations that the system allows one to realizenconsiderable analysis time savings by adapting the totalncolumn length to the specific sample requirements andor to the stage of method development wherein one isnworking. During method development, a separation on anshort column length can first be used to rapidly gainninsight into the composition of the sample, leaving fewernruns to be done on a column of maximal length (offeringnefficiencies that are inaccessible with individual columnnsystems). The ease with which information can be obtainednon columns of different lengths can furthermorenbe exploited for screening purposes to detect coelutingncomponents in a stage wherein they still appear completelynunresolved (i.e., have a resolution well below Rsn) 0.5).