A column capacity study of single, serial, and parallel linked rod monolithic high performance liquid chromatography columns.

The loading capacity of rod monolithic C18 columns was found to be sensitive to the injection volume, but essentially insensitive to the mass loading for a separation of oligostyrenes. When rod monoliths were coupled in series the injection volume loading increased, as too did the resolution of the oligomers, but at the expense of separation time. The volume load capacity of these serially connected monoliths was, however, not directly proportional to the number of columns connected. The volume load capacity was, however, directly proportional to the number of columns when the monoliths were connected in parallel and the flow stream split between each of the monolithic channels. When the number of monoliths in each channel equaled the number of monoliths that were connected in a single channel serial system the peak capacity and retention time was equivalent for both systems, but the volume load capacity of the parallel system was twice that of the serial connection each time the number of channels doubled. The results of this study indicate that parallel connection of rod monolithic columns may be useful for preparative scale and multidimensional separations where it is important that the volume load capacity is high.