UPLC-MS-based analysis of human plasma for metabonomics using solvent precipitation or solid phase extraction.

Area of Science:

• Metabolomics and Analytical Chemistry
• Biomarker Discovery

Background:

• Accurate global metabolite profiling of human plasma is crucial for metabonomic analysis.
• Traditional protein precipitation methods can introduce variability in LC-MS data.

Purpose of the Study:

• To investigate factors influencing valid global metabolite profiles from human plasma.
• To compare protein precipitation versus solid phase extraction (SPE) for sample preparation in LC-MS metabonomics.

Main Methods:

• Human plasma samples were prepared using either organic solvent (methanol/acetonitrile) precipitation or C18 SPE.
• Chromatography employed a reversed-phase gradient system with ultra-high performance liquid chromatography (UPLC).
• Mass spectrometry analysis utilized positive electrospray ionization and time-of-flight detection.

Main Results:

• Reproducibility for solvent-precipitated plasma required system "conditioning" with matrix injections.
• Solid phase extraction (SPE) demonstrated significantly improved methodological repeatability compared to protein precipitation.

Conclusions:

• SPE is a superior sample preparation technique for enhancing the repeatability of human plasma metabolite profiling.
• Optimized sample preparation is critical for obtaining valid and reproducible metabonomic data via LC-MS.