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FOR EXPERT REVIEW PANEL USE ONLY
NOT FOR DISTRIBUTION
2
Method Safety Concerns:
As noted by the study director, there are no major or unique hazards noted for this method
beyond those found and common to typical analytical laboratories.
Pros/Strengths:
General:
Diels-Alder reaction is specific to vitamin D
2
and D
3
(conjugated diene) which are absent in
common plant sterols.
Method is an LC-MS/MS method offering excellent selectivity.
The PTAD-D adducts produce simplified chromatography and mass spectra contributing to overall
selectivity and improved S/N.
Multiple mass transitions are used, one for quantitation and qualitative confirmation.
Internal standardization is used to facilitate quantitation and method robustness.
Supporting Data
•
Performance Characteristics / Supporting Data
Multi-Laboratory Testing (MLT)
The submitted MLT data include Vitamin D results for 20 SPIFAN test materials including all
fortified (16) and unfortified (4) matrices as well as SRM 1849a and SRM 1869 (proposed).
Vitamin D
3
results are reported for all but one matrix, 1869 (proposed). Vitamin D
2
data is
reported for this matrix. It is noted that the majority of fortified matrices available contain
only vitamin D
3
.
12 labs were enrolled in the MLT. Three labs did not report data by study deadline.
Results for nine laboratories were used to evaluate method repeatability and reproducibility vs
SMPR.
The submitted data were evaluated for overall mean, repeatability relative standard deviation
(RSDr) and reproducibility relative standard deviation (RSDR).
Cochran tests were utilized to determine outliers. Only a single pair of results for vitamin D2
was excluded as Cochran outliers. No other outliers were identified.
Precision as repeatability (RSDr) – Though not required for this MLT, values for repeatability
were reported from this study and range from 1.9–5.8% RSDr. These values are well within