Question

explain how size exclusion chromatography can be used to change the buffer of a protein sample (buffer exchange). How does this process work and what does the buffer of the sample end up changing?

Answer 1

Size exclusion chromatography is the technique of separation of components based on their molecular size. Separation is achieved by the differential exclusion of the sample molecules as they pass through a bed of porous particles. Buffer exchange occurs when a sample protein is passed through a column containing buffer exchange materials such as resins. Salts and small molecules flow through the resin pores. Larger molecules flow faster through the column. In this way, protein molecules are separated from salts and other smaller molecules in the sample and desalted proteins are collected separately.