title: Development of High-purity Certified Reference Materials for 17 Proteinogenic Amino Acids by Traceable Titration Methods.
abstract: To ensure the reliability of amino acid analyses, the National Metrology Institute of Japan of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed high-purity certified reference materials (CRMs) for 17 proteinogenic amino acids. These CRMs are intended for use as primary reference materials to enable the traceable quantification of amino acids. The purity of the present CRMs was determined based on two traceable methods: nonaqueous acidimetric titration and nitrogen determination by the Kjeldahl method. Since neither method could distinguish compounds with similar structures, such as amino acid-related impurities, impurities were thoroughly quantified by combining several HPLC methods, and subtracted from the obtained purity of each method. The property value of each amino acid was calculated as a weighted mean of the corrected purities by the two methods. The uncertainty of the property value was obtained by combining measurement uncertainties of the two methods, a difference between the two methods, the uncertainty from the contribution of impurities, and the uncertainty derived from inhomogeneity. The uncertainty derived from instability was considered to be negligible based on stability monitoring of some CRMs. The certified value of each amino acid, property value with uncertainty, was given for both with or without enantiomeric separation.
authors.affiliation: Bio-Medical Standards Section, Organic Analytical Chemistry Division, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology.
authors.forename: Megumi
authors.initials: M
authors.lastname: Kato
authors.forename: Taichi
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato
authors.forename: Sakae
authors.initials: S
authors.lastname: Eyama
authors.forename: Mari
authors.initials: M
authors.lastname: Goto
authors.forename: Mariko
authors.initials: M
authors.lastname: Yoshioka
authors.forename: Akiko
authors.initials: A
authors.lastname: Takatsu
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000592:standards*; D011506:Proteins / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results; D013237:Stereoisomerism; D035501:Uncertainty
chemical_list: D000596:Amino Acids; D011506:Proteins