Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Certifying NIST Standard Reference Material 2389a, Amino Acids in 0.1 mol/L HCl Absolute Quantification by ID LC-MS/MS



Mark S. Lowenthal, David M. Bunk, Karen W. Phinney


An isotope-dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS) reference measurement procedure was developed to accurately quantify amino acid concentrations in NIST Standard Reference Material (SRM) 2389a Amino Acids in 0.1 mol/L Hydrochloric Acid. Seventeen stable amino acids were quantified using multiple-reaction monitoring (MRM). Results were compared to gravimetric measurements from the preparation of SRM 2389a, a reference material developed at NIST and intended for use in intra-laboratory calibrations and quality control. Quantitative mass spectrometry results and gravimetry values were statistically combined into certified NIST values with associated error estimates. Coefficients of variation (CV) for the repeatability of the amino acid measurements ranged from 0.33% to 2.3% with an average CV of 0.86%. Relative expanded uncertainties of the measurement precision (including Types A and B uncertainties) ranged from 1.6% to 4.8% among amino acids with an average expanded uncertainty of 2.3%. Mean accuracy of the LC-MS/MS measurements with gravimetry agreed to within |1.1|% for all amino acids. NIST SRM2389a is currently available for characterization of routine methods and serves as a standard for higher order measurement traceability. This is the first time an ID-LC-MS/MS methodology has been applied for quantifying amino acids in a NIST SRM material.
Analytical and Bioanalytical Chemistry


amino acids, standard reference material, mass spectrometry, isotope dilution


Lowenthal, M. , Bunk, D. and Phinney, K. (2010), Certifying NIST Standard Reference Material 2389a, Amino Acids in 0.1 mol/L HCl Absolute Quantification by ID LC-MS/MS, Analytical and Bioanalytical Chemistry, [online], (Accessed April 23, 2024)
Created May 18, 2010, Updated February 19, 2017