Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry for Quantitative Amino Acid Analysis

Area of Science:

• Bioanalytical Chemistry
• Analytical Chemistry
• Mass Spectrometry

Background:

• Amino acid analysis has transitioned from a qualitative to a quantitative technique in bioanalysis.
• Mass spectrometry (MS) methods, such as electrospray ionization and matrix-assisted laser desorption ionization, have largely replaced traditional amino acid analysis for qualitative protein and peptide characterization.
• Accurate quantification of proteins and peptides is crucial for applications like clinical diagnostics.

Purpose of the Study:

• To develop a highly accurate and precise amino acid analysis method for quantifying protein and peptide standard reference materials (SRMs) at the National Institute of Standards and Technology (NIST).
• To leverage isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS), a technique routinely used at NIST for certifying analyte concentrations, for amino acid quantification.

Main Methods:

• Development of a novel amino acid analysis method.
• Utilized isotope dilution coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS).
• Application of the method for assigning concentration values to protein and peptide SRMs.

Main Results:

• A new, highly accurate and precise method for amino acid quantification using isotope dilution LC-MS/MS has been established.
• This method is suitable for certifying the concentration of protein and peptide SRMs.
• The developed method supports the calibration of various protein and peptide assays, including those in clinical diagnostics.

Conclusions:

• Isotope dilution LC-MS/MS provides superior accuracy and precision for amino acid analysis compared to older methods.
• This advanced analytical technique is essential for producing reliable SRMs for proteins and peptides.
• The method contributes to the accuracy of protein and peptide measurements in diverse bioanalytical applications.