FLOW RATES FOR USE WITH JORDI™ GPC/SEC COLUMNS

The 10mm x 500mm Jordi™ GPC columns is larger than the typical 7.8mm x 300mm GPC Columns.

• Larger Injection Volumes are possible with Jordi™ Columns without overload.
• Column flow rates for Jordi™ columns are typically 1.5mL/minute. Higher plate counts can be obtained at lower linear velocities.
• Normal analysis times are about 22 minutes at 1.5mL/minute which can be cut into half when run on a Jordi™ column at 3.0mL/minute with minimum loss of plate count.

The most optimal flow rate is always the lowest possible when analyzing polymers. This may not be true for small molecules.

If you change flow rate to increase efficiency for a narrow standard, a more narrow peak will result. If the standard is dispersed, it will either exhibit a broader peak as the different MW species start to separate, or it will remain somewhat the same.

When separating a polymer distribution, it is generally believed that the optimum efficiency can be determined by measuring the plate count of an unretained molecule such as toluene at different flow rates. This will not be true for polymer separation as the optimal flow rate is much lower than that of a smaller molecule.

See the chart above: Higher resistance to mass transfer of the polymer as illustrated above by the Van Deemter Plots.