Abstract
Sodium dodecyl sulfate (SDS) plays a pivotal role in protein denaturation, tissue extraction, and protein mass-based electrophoretic separations. However, even modest concentrations of SDS can cause column overpressure, retention time shifts, and ionization signal suppression during liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses. Thus, SDS removal is a critical step for LC-MS/MS analysis of protein digests containing SDS. This study describes an inexpensive and high-throughput method to remove SDS from protein digests using weak-anion exchange (WAX) resins in 96-well filter plates. Requiring less than 3 min, this method can reduce SDS concentrations from 0.1-0.4% to less than 5 ppm and from 0.6-1% to less than 100 ppm. After SDS removal, the recoveries of unmodified tryptic peptides and phosphorylated peptides (at 94.3 nM) were ∼90% and ∼70%, respectively. Additionally, when using aqueous 1% SDS to solubilize trastuzumab-spiked mouse serum and subsequently removing the SDS using the WAX resin, quantitation of trastuzumab exhibited excellent linearity (R2 = 0.9996) together with a low coefficient of variation (<10%). Calculated concentrations were within 20% of the expected value for spiked standard samples (0.5, 1, and 2 μg/mL trastuzumab in mouse serum). The method is about 20× more cost-effective versus commercialized SDS removal kits and both the resin and filter plate are readily available, so the method should easily transfer to other laboratories.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call