CRB-FCC: A Standardized Nontargeted Analysis for Formula Assignment and Structure Annotation.

Area of Science:

• Analytical Chemistry
• Chemical Analysis
• Spectroscopy

Background:

• Nontargeted analysis using LC-MS is crucial for identifying chemicals in real-world samples.
• Resolving structures of unknown compounds from mass spectra is a significant challenge due to limited databases and poor spectral quality.
• Existing methods often fail with low-quality or absent mass spectra.

Purpose of the Study:

• To develop a robust method for identifying unknown chemicals in complex samples.
• To overcome the limitations of traditional mass spectral matching in nontargeted analysis.
• To improve the accuracy and reliability of chemical structure elucidation.

Main Methods:

• Developed the Fragmental Chain Characterization (FCC) method for formula assignment from mass spectra.
• Integrated FCC with the Chromatographic Retention Behavior (CRB) approach for compound identification across samples.
• Validated the CRB-FCC method using 1,475 chemical standards and applied it to identify impurities in biosynthesized plastics.

Main Results:

• The CRB-FCC method accurately annotates compounds even with poor quality or missing mass spectra.
• Demonstrated consistent identification of compounds across samples using retention times and assigned formulas, despite spectral variations.
• Successfully identified unknown yellow-hue impurities in biosynthesized plastics when combined with NMR.

Conclusions:

• CRB-FCC offers a standardized protocol for data acquisition and interpretation in nontargeted analysis.
• This method significantly improves the identification of unknown compounds compared to conventional techniques.
• CRB-FCC is expected to accelerate the adoption of nontargeted analysis in academia and industry.