Serum protein profiling using surfactant-aided matrix-assisted laser desorption/ionization mass spectrometry Original Research Article

It has been shown previously that sodium dodecyl sulfate (SDS) can be used at its critical micellar concentration to increase the number of peptides detected in a peptide mixture by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Here we demonstrate that, in a similar fashion, preparation of peptides and low molecular weight proteins from serum using SDS micelles improves the information content in MALDI-MS. In particular, the addition of SDS yielded a 30% increase in the number and a 50% increase in the abundance of low molecular weight (<6000 Da) analytes. C18 ziptips and C18 magnetic beads were used as pre-cleaning steps for comparative analysis and it was found that magnetic beads were more suitable for pre-cleaning prior to combining the eluent with SDS. The non-ionic surfactant n-octyl-β-d-glucopyrinoside yielded improved ion abundances of peptides with masses above 6000 Da, although these increases are less dramatic than those found with SDS. These results demonstrate that surfactant-aided MALDI-MS can lead to an increase in the amount of information obtained from complex mixtures of peptides/proteins. Such improvements may prove advantageous for applications such as those focused on protein profiling.