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Additional data on Multi-Laboratory Validation – Vitamin C method AOAC First
Action 2012.22 / F. Martin, NRC/AS
23.Nov.2015
CONFIDENTIAL
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C O N C L U S I O N
This additional MLT was organized to collect new precision data (repeatability and reproducibility)
of samples which presented higher variability numbers than the rest of the matrices during the MLT.
Two fresh samples (Infant Formula RTF Milk Based and Adult Nutritional Powder Low Fat) were
dispatch to twelve laboratories.
The results for the Adult Nutritional Powder Low Fat product are now well within the SMPR
requirements. Regarding the Infant Formula RTF Milk Based, even if the precision numbers
improved, they remained slightly outside of the requirements.
One of the participant lab decided to analyse the four bottles received in duplicates. To mirror this
experiment the decision was made to also analyse the samples at NRC, using a different method
(AOAC Official method 985.33). Both sets of data suggest that the higher variability observed for the
RFT sample come from variability within the samples, and not from the method.
These results show that AOAC Official method 2012.22 comply with the requirements set in the
corresponding SMPR, and thus is fit for purpose for the analysis of ascorbic acid (vitamin C) in infant
formula and adult/pediatric nutritionals. The authors thus recommend that the method should be
proposed for AOAC Final Action Official Method status.
AOAC OMB Meeting Book
380