Mediating the liquid chromatography wall effects using diamagnetic repulsion

The variation in packing density as a function of column radius has been demonstrated to be a major limitation in the efficiency of liquid chromatography columns. Referred to as the wall effects, these changes in bed structure across the diameter of the column cause the distortion of eluting solute profiles from flat discs to parabolic in shape. These parabolic profiles are measured as having a faster, more efficient migration in the column centre with a slower, less efficient migration at the column wall. The possibility of using diamagnetic repulsion as an approach to mediate these effects was investigated using an on-column visualisation chromatography system. A series of magnetic fields were applied to various columns formats to determine if solute migration from the column wall cold be achieved. A distinct migration of solute from the column walls was observed for small scale pipette columns indicating the principle of diagenetic repulsion may be a feasible approach. However, migration of iodine in both a 15 mm and 4.0 mm internal diameter (ID) column indicated no repulsion was achieved. Discrepancies between these results may have been a result of changed magnet array position relative to the chromatography column.