Electrospray mass spectrometry (ESI-MS) is a versatile analytical tool for biomolecular protein analysis and proteomics. One important area is to study protein structure and composition in which peptides and proteins can be ionized with multiple charges via electrospray ionization. Based on the charge envelope, the molecular weight can be easily determined using manual or automated deconvolution.<br/>In this application, a direct and robust analysis method for protein identification is introduced using an expression-L compact mass spectrometer (CMS) (Advion Inc., Ithaca, NY) coupled with an open port sampling interface (OPSI) connected to the ESI source. The charge deconvolution function implemented in the data analysis software will also help users more easily determine the molecular weight of the target protein. The Bovine Serum Albumin (BSA) protein is used as a demonstration of the OPSI-ESI-CMS method. The concentration of BSA used was 30 µM in 100 mM aqueous ammonium acetate. 2µl of the BSA solution was used for OPSI-ESI-CMS analysis resulting in an example spectrum shown in figure 1a. The calculated uncharged molecular weight of BSA (Sigma part number A7638) is shown in figure 1b with a MW of 66462.4, which is close to the value of 66463 from Swiss-Prot. More proteins (apomyoglobin, lysozyme, enolase and a human IGG) will be used to evaluate the OPSI-ESI-CMS method for protein molecular weight determination.

Rapid protein identification with an open port sampling interface coupled to a compact mass spectrometer

256th National Meeting (2018)

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