Streamlined MRM method transfer between instruments assisted with HRMS matching and retention-time prediction.

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Environmental Science

Background:

• Multiple reaction monitoring (MRM) using liquid-chromatography tandem mass spectrometry (LC-QqQ-MS/MS) offers high sensitivity for trace small molecule analysis in complex matrices.
• The reliance on costly and often unavailable authentic standards limits the widespread adoption of MRM methods.
• A need exists for practical solutions to enable MRM method transfer and facilitate small molecule quantification without direct standard use.

Purpose of the Study:

• To develop a practical platform for transferring MRM methods between different LC-QqQ-MS/MS instruments.
• To enable confident small molecule identification and quantification without the need for authentic standards.
• To leverage high-resolution mass spectrometry (LC-HRMS) and retention time prediction for method transfer.

Main Methods:

• Developed a platform integrating LC-HRMS and retention time (RT) prediction for MRM method transfer.
• Utilized accurate mass measurements from LC-HRMS and MS/MS fragments from literature.
• Employed retention time matching, peak matching, and a quantitative structure retention relationship (QSRR) model for compound identification.
• Validated the platform's robustness using spiked environmental chemicals in various complex matrices (sludge water, urine, cell extracts).

Main Results:

• The platform successfully transfers MRM methods between different LC-QqQ-MS/MS instruments.
• Integration of LC-HRMS and RT prediction allows for confident small molecule identification without authentic standards.
• The QSRR model, based on random forest feature selection, achieved a Pearson r² of 0.63 for RT prediction.
• Robustness was demonstrated across diverse sample types, including environmental, biological, and cellular matrices.

Conclusions:

• The developed platform provides a practical and cost-effective solution for MRM method transfer.
• This approach significantly reduces the dependency on expensive and scarce authentic standards for small molecule analysis.
• The validated platform enhances the reliability and accessibility of trace-level small molecule quantification in complex samples.