A new split-flow injector for preparative liquid chromatography columns. Annular injection system.
ABSTRACT The packing of large-diameter columns for liquid chromatography is still difficult and numerous publications have reported results from tests which prove the packing is heterogeneous. The slurry is more compact in the wall region and this reduces the flow of the mobile phase, leading to distortion of the sample zone in the column and generation of peak tailing. A new type of injection system for the head of the column has been developed which divides the flow of the solvent from the pump into two parts. One, without sample, is directed to a crown injector, close to the wall. By adjusting the ratio of this flow to that of the bulk flow it is possible to increase the speed of the mobile phase in this part of the stationary phase and reduce distortion of the sample zone. The other part of the solvent carries the sample to the stationary phase through a distributor. The results demonstrate the benefits of this annular injection system, which include increased efficiency and improved column stability.
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ABSTRACT: Axial compression of the stationary phase is an easy technique for packing preparative liquid chromatography columns. However, the compression piston often needs an important external device to move the external jack. A new type of column is described which uses an auto-compression system to move the piston and compress the packing material. The system is fitted with a new annular injector which is known to reduce the peak tailing. The results of the tests demonstrate the ease of use of this column, its efficiency and stability.Analytical and Bioanalytical Chemistry 02/2003; 375(1):112-9. · 3.58 Impact Factor