ALEU-1: Certified Reference Material of L-leucine

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

The certified value represents the purity of L-leucine 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-leucine. It is intended that UCRM accounts for every aspect that reasonably contributes to the uncertainty of the certified value.

Table 1: Certified value for ALEU-1

Substance Molecular formula Mass fraction g/g
L-leucine C6C13NO2 0.9930 ± 0.0040

Table 2: Information values for impurities in ALEU-1

Substance Molecular formula Mass fraction g/g
isoleucine C6C13NO2 2.3 x10-3
methionine C5C11NO2S 6.8 x10-5
phenylalanine C9C11NO2 3.8 x10-6
valine C5C11NO2 2.7 x10-5

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-leucine. A minimum sample mass of 10 mg is recommended.


It is recommended that the material be stored in a controlled cold temperature environment such as a refrigerator between 2 to 8°C.


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 ALEU-1

Substance Uk=2
L-leucine 0.0040 0.0020 0.0017 0.00057 0.0000 0.00096

Date of issue: October 2017
Date of expiry: October 2022

Date modified: