AMET-1: Certified Reference Material of L-methionine

The following tables show those constituents for which certified and information values have been established for this L-methionine pure substance certified reference material (CRM).

The value represents the purity of L-methionine and is based on results from data generated at NRC using quantitative proton nuclear magnetic resonance spectroscopy (1H‑qNMR). The expanded uncertainty (UCRM) in the certified value is equal to U = kuc where uc is the combined standard uncertainty calculated according to the JCGM Guide [1] and k is the coverage factor. A coverage factor of two (2) was applied for L-methionine. It is intended that UCRM accounts for every aspect that reasonably contributes to the uncertainty of the certified value.

Table 1: Certified value for AMET-1

Substance Molecular formula Mass Fraction
g/g
L-methionine (a) C5H11NO2S 0.9989 ± 0.0034

Table 2: Information value for AMET-1

Substance Molecular formula Mass Fraction
g/g
water (b) H2O 9.9×10–5

Coding

The coding refers to the instrumental method of analyte determination.

  • a - Quantitative proton nuclear magnetic resonance spectroscopy (1H-qNMR)
  • b - Karl Fischer titration

Intended use

This reference material is primarily intended for use in the calibration of procedures and the development of methods for the determination of L-methionine. A minimum sample mass of 15 mg is recommended.

Storage

It is recommended that the material be stored in a controlled cold temperature environment such as a refrigerator between 2 to 8 °C. After use the bottle should be tightly closed and stored properly.

Uncertainty

Included in the combined uncertainty estimate (uc) are uncertainties in the batch characterization (uchar), uncertainties related to possible between-bottle variation (uhom), uncertainties related to stability (ustability) and uncertainties related to variability between different qNMR signals (umethod). Expressed as standard uncertainties, these components are listed in Table 3.

Table 3: Uncertainty components for AMET-1

Substance Uk=2
g/g
uc
g/g
uchar
g/g
uhom
g/g
ustability
g/g
umethod
g/g
L-methionine 0.0034 0.0017 0.0017 0.0000 0.0000 0.0002

Date of issue: February 2017
Date of expiry: February 2022
Revised: December 2017 (homogeneity and uncertainty sections, table 3 and editorial updates)

Date modified: