Surfactants are often used to solubilize cell membrane and/or to prevent peptide/protein to be adsorbed on the container surface. However, the presence of surfactant may deteriorate LC column and LC/MS system, resulting in poor repeatability. By using a column-switching sample preparation column, MSpak GF-4A, surfactants can be removed prior to the sample being introduced to the analytical column. Therefore, good repeatable analysis can be achieved and the time required for sample preparation can be reduced.
In the following system diagram, in the initial step, the surfactant in the sample is adsorbed to GF-4A by hydrophobic interactions and the protein sample is introduced into the analytical column and separated.
The next step involves switching the hexagonal valve such that a regenerating solution (such as 10 mM CH₃COONa aq. (pH 7.0)/CH₃CN=30/70) flows only to GF-4A and washes out the adsorbed surfactant, regenerating GF-4A.



Sample: BSA

Pretreatment
Column         : Shodex MSpak GF-4A (4.6 mm I.D. x 10 mm)
Eluent         : 50 mM Sodium phosphate buffer (pH 7.0) + 150 mM NaCl
Flow rate      : 1.0 mL/min
Column temp.   : Room temp.
Switching time : 5 min
Analysis 
Column         : Shodex PROTEIN KW-804 + KW-802.5 (8.0 mm I.D. x 300 mm each)  
Eluent         : 50 mM Sodium phosphate buffer (pH 7.0) + 150 mM NaCl
Flow rate      : 1.0 mL/min
Detector       : UV (280 nm)
Column temp.   : Room temp.