Mass spectrometry based systems and methods for implementing multistage MS/MS analysis for identification of experimental glycolipid samples

A mass spectrometry (MS) based system configured to implement multi-stage MS/MS analysis for identification of experimental glycolipid samples, the MS based system comprising:

• a mass spectrometer configured to receive and analyze an experimental glycolipid sample to determine experimental MS/MS spectral data of the experimental glycolipid sample;
• a reference spectral database configured to store a plurality of reference glycolipid datasets, each of the reference glycolipid datasets corresponding to a reference glycolipid and comprising at least (a) reference glycan fragment data defining MS/MS spectra of a glycan portion of the reference glycolipid, and (b) reference lipid and/or glycolipid fragment data defining MS/MS spectra of a lipid portion of the reference glycolipid;
• a memory storing program instructions;
• and
• a processor communicatively coupled to the memory and the reference spectral database,
• wherein the processor is configured to execute the program instructions to cause the processor to:
• (1) implement a first stage analysis of glycan fragment data comprising:
• determining, from the experimental MS/MS spectral data, experimental glycan fragment data defining MS/MS spectra of a glycan portion of the experimental glycolipid sample,
• identifying a matching reference glycan of a candidate reference glycolipid selected from the reference spectral database, wherein fragment data of the matching reference glycan comprises one or more MS/MS spectral values that correspond to one or more MS/MS spectral values of the experimental glycan fragment data,
• determining, based on the matching reference glycan of the candidate reference glycolipid, a glycan structure of the glycan portion of the experimental glycolipid, and
• (2) implement a second stage analysis of lipid and/or glycolipid fragment data comprising:
• determining, from the experimental MS/MS spectral data, experimental lipid and/or glycolipid fragment data defining MS/MS spectra of a lipid portion of the experimental glycolipid sample,
• rule-based shifting, by the processor, one or more mass values of the reference lipid and/or glycolipid fragment data of the candidate reference glycolipid, while maintaining, during the rule-based shifting, the experimental glycan fragment data identified during the first stage analysis, to generate shifted reference lipid and/or glycolipid fragment data,
• performing a spectral comparison of one or more MS/MS spectral values of the shifted reference lipid and/or glycolipid fragment data with one or more MS/MS spectral values of the experimental lipid and/or glycolipid fragment data, and
• determining, based on reference lipid and/or glycolipid fragment data of the candidate reference glycolipid, a lipid structure of the lipid portion of the experimental glycolipid,
• wherein, based on the spectral comparison, the experimental glycolipid sample is determined to be of a same glycolipid species as the candidate reference glycolipid, the lipid structure of the lipid portion of the experimental glycolipid being different from a lipid structure of the candidate reference glycolipid as characterized by a difference between the experimental lipid and/or glycolipid fragment data and the reference lipid and/or glycolipid fragment data.