EXPRESS: Precursor/Fragment Ion Identification from Bulk Analysis of a Mixture through Two-Dimensional Correlation...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Mass Spectrometry

Background:

• Mass spectrometry (MS) analysis of complex mixtures faces challenges like isobaric overlap and competitive ionization.
• Current methods, such as chromatography-coupled MS and tandem-MS, necessitate physical separation or isolation of analytes.
• These limitations hinder efficient and accurate identification of compounds in intricate samples.

Purpose of the Study:

• To adapt two-dimensional (2D) correlation techniques from optical spectroscopy for application in mass spectrometry.
• To develop a method for identifying precursor and fragment ion pairs directly from complex mixtures.
• To obviate the need for sequential separation or isolation of analytes in MS analysis.

Main Methods:

• Application of 2D correlation techniques to mass spectrometry data.
• Development of a mathematical framework to threshold correlation-derived metrics.
• Prediction of shared molecular origin for mass-spectral signals.
• Utilizing direct analysis in real time (DART) mass spectrometry for data acquisition.

Main Results:

• Successfully identified precursor and fragment ion pairs from a two-component mixture without analyte separation.
• Developed metrics to predict whether mass-spectral signals originate from the same molecule.
• Achieved greater than 90% accuracy in identifying single-analyte spectra using NIST MS Search 2.2 software.

Conclusions:

• 2D correlation techniques can be effectively adapted to mass spectrometry for analyzing complex mixtures.
• The developed mathematical framework enables accurate analyte identification by linking precursor and fragment ions.
• This approach offers a powerful alternative to traditional separation-based methods and is applicable to various time-dependent MS datasets.