What does a fractionation range refer to in chromatography?

A fractionation range in chromatography specifically refers to the range of molecular weights that can be effectively separated during the process. This is particularly relevant in techniques such as size-exclusion chromatography, where molecules are separated based on their size and shape. Larger molecules are eluted first as they cannot enter the pores of the stationary phase, while smaller molecules enter the pores and are thus delayed.

The correct understanding of the fractionation range implies that it defines the specific molecular weight limits within which the method is effective for separation. This is crucial in biochemistry as it allows researchers to isolate proteins or other biomolecules of specific sizes for further analysis or experimentation, ensuring that the method is suited to the intended application.

In contrast, the other options relate to different aspects of chromatography that do not define the fractionation range. For instance, while protein concentrations and binding affinities are important parameters in various chromatography methods, they are not directly tied to the specific range of molecular weights that can be separated in the chromatography process.