Difference Between “M” and “L” Designations in Shodex GPC Columns

Record: 622

Category: Column Selection
Product: GPC
Sample: N/A

Question

Some GPC columns have an “M” or “L” at the end of the column name. Are mixed-gel columns better, and what is the difference between these designations?

Answer

In Shodex GPC columns, the “M” and “L” designations both refer to mixed-gel configurations, meaning the column contains packing materials with multiple pore sizes to extend molecular-weight coverage. However, the internal pore-size distribution differs between the two designs.

M-type columns (e.g., KF-806M) contain a homogeneous blend of different pore-size gels mixed uniformly throughout the column. This design provides broad molecular-weight coverage and is often selected for samples with wide molecular-weight distributions where overall range is prioritized.

L-type columns (e.g., KF-806L) use a more linear or staged pore-size distribution, effectively arranging pore sizes in a progression from smaller to larger. This configuration often produces a smoother, more linear calibration curve across the molecular-weight range and can provide improved resolution in lower molecular-weight regions. For this reason, L-type columns are frequently preferred when accurate molecular-weight determination and calibration curve quality are critical.

Neither design is universally better. The appropriate choice depends on whether the priority is broad distribution coverage (M-type) or calibration accuracy and enhanced resolution in specific MW regions (L-type).

Recommended Application:

• Comparison of Calibration Curves: Linear-Type and Mixed-Gel Type Columns
  Illustrates differences in calibration behavior between linear and mixed-gel GPC columns and helps guide column selection based on resolution and MW range requirements.

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