Removal of sodium dodecyl sulfate from protein and peptide samples with cross‐linked [Os(dmebpy)2Cl]+/2+‐derivatized acrylamide and vinylimidazole copolymer

Abstract

RationaleSodium dodecyl sulfate (SDS) is widely used for the solubilization and denaturation of proteins, but it interferes with liquid chromatography/mass spectrometry (LC/MS), suppressing protein signals or forming adduct ions. A quick and effective clean‐up technique of SDS is essential for MS analysis of proteins. Ion‐exchange spin columns are commonly used for SDS removal in protein samples.MethodsA bulk sample of insoluble, cross‐linked [Os(dimethylbipyridine)2Cl]+/2+‐derivatized poly(acrylamide)‐poly(vinylimidazole) copolymer was synthesized and broken into small particles. The polymer was activated by washing with 1:1 ACN/water 50 mM triethylammonium phosphate 0.05% TFA, 0.1% TFA ACN and then 0.1% TFA water. Under acidic aqueous conditions, SDS adsorbs on the activated surfaces of the Os‐complexed copolymer particles, but not the proteins and peptides in the same mixtures. Thus, the copolymer can be used to remove SDS from protein and peptide samples. The copolymer‐adsorbed SDS is removed by washing with 0.1% TFA ACN, permitting re‐use of the copolymer.ResultsStandard myoglobin and some practical protein samples from a biochemistry lab spiked with different concentrations of SDS were successfully cleaned up using this Os‐copolymer for LC/MS analyses. Up to 0.2% (w/v %) of SDS can be successfully removed from those protein samples.ConclusionsThis Os‐complexed copolymer provides a new alternative for quick cleanup of SDS from protein samples, and can serve as a new class of metal complex based anion exchanger for protein purification. Copyright © 2016 John Wiley & Sons, Ltd.