Table 1 Advantages and limitations of SEC-MALS vs. IEX-MALS.
Method parameters | SEC-MALS | IEX-MALS |
|---|---|---|
Principle of separation | Hydrodynamic size | Charge |
Parameters that increase selectivity and resolution | Restricted Different columns can be used with different fractionation range, resin particle size, matrix or different column length | Varied Different steps/gradient running programs, gradient slope, pH or salt gradient, type of salts, type of buffer, resin particle size, different matrixes, type of column (CIEX/AIEX) and column length |
Injected volume | Limited | Unlimited* |
Sample concentration | Concentrated sample | Diluted or concentrated sample |
Sample buffer | As desired | Conditions that allow binding |
Equilibration time | Long | Short |
Flexibility of changing parameters during the run | Not flexible | Flexible |
Conjugate analysis (for modified proteins) achieved by using RI signal | Easy to perform | More laborious RI signal changes during salt or pH gradients. Requires high sample concentration |
Analysis of low masses | Not recommended | Possible |
Analysis of mixtures of proteins with similar size | Not recommended | Recommended |
Complexity of experiment | Easy and intuitive | Requires prior optimization or knowledge of conditions |
