Shim-pack MAYI 2 Series - Features
HPLC Column
Remove/Elute Macromolecular Compounds
The analytical results for the molecular weight standard reagent (pullulan) for size-exclusion chromatography are shown below. With ordinary silica gel, pullulan is retained through interactions; however, with a hydrophilic coating, macromolecules are eluted without retention due to the size-exclusion effect. (Because size exclusion separates molecules by size, the exclusion limit may differ even for molecules with the same molecular weight.)
*The stationary phase was not modified; only a hydrophilic coating was applied.
Achieves Faster Cleanup
Through optimization of the packing material and column body, the Shim-pack MAYI 2 Series supports a maximum pressure of 60 MPa (50 MPa for a 2 mm inner diameter). This enables the flow rate during sample injection to be increased, allowing macromolecules to be removed more rapidly and efficiently. The following example shows the removal effect using casein as a model macromolecular compound. When the casein peak area obtained without a column was set to 100%, the removal rate was calculated from the area of non-retained casein at each flow rate. The results show that increasing the flow rate enables more efficient removal.
- *The molecular weight of casein varies by type: α-casein is approximately 2.5–2.7×10⁴, and β-casein is approximately 1.7–2×10⁴.
Therefore, some of the casein with lower molecular weights is considered to be partially retained.
High Macromolecular Compound Removal Rate and High Recovery of Low-Molecular-Weight Compounds
In addition to its high macromolecule removal capability, the Shim-pack MAYI 2 Series can retain low-molecular-weight compounds with high recovery. The results below compare the recovery with other online clean-up columns using multiple low-molecular-weight compounds with different Log D values (a pH-dependent hydrophobicity (lipophilicity) index). The stationary phase was C18 in all cases. For compounds with Log D values above 1, Shim-pack MAYI 2 C18-60 shows the highest recovery.
Simplifies Pretreatment and Improves Analytical Robustness
The Shim-pack MAYI 2 Series is particularly effective in trap-and-elute systems, removing macromolecules unnecessary for analysis and efficiently introducing target compounds into the downstream analytical column. This not only simplifies pre-treatment, but also prevents macromolecules from flowing into and clogging the analytical column or detector, enabling robust analysis. The following shows chromatograms and pressure changes when untreated milk samples were injected multiple times into a Shim-pack MAYI 2 column and a commonly used column.
With the commonly used column, the pressure increased as the number of injections increased, rising by approximately 7.5 MPa after 60 analyses. In contrast, with the Shim-pack MAYI 2, virtually no pressure change occurred even after more than 100 analyses.
Shim-pack MAYI 2 C18-60 (30 mm x 2.0 mm, 50 μm)
Chromatogram
Pressure curve
Commonly used C18 column (10 mm x 4.6 mm, 5 μm)
Chromatogram
Pressure curve