84 / 123
Collaborative Study Report: Method 2011.20 Nucleotides by HPLC-UV
Page 19
Method Accuracy
Method accuracy was assessed in accordance with SPIFAN procedures based on results of the NIST1869a
samples tested as part of the final study sample sets (Table 3). The
p
-value of 0.32 indicates no bias was
found against the certified value (5). Placebo samples not fortified with vitamin D returned negligible results
for vitamin D as expected.
Table 3: Accuracy results for vitamin D in NIST1849a CRM
FORTIFIED: NIST1849a CRM KGSZ273/LTCT316
Seq.
Bias
Analyte
Vitamin D3
Symbol
Value
1
Overall mean of all data (grand mean)
x
10.2
µg hg
-1
2
Total number of replicates
Sum(n(L))
36
2
Certified value (ug/hg)
µ
11.1 µg hg
-1
3
Uncertainty
U
CRV
1.7 µg hg
-1
4
Coverage factor
k
2.0
5
Students's test-statistic
t
STAT
1.0
6
Degrees of freedom
DF
63.0
7
p-value
0.32
Method Applicability
The Vitamin D SMPR applicability statement:
“
Determination of total vitamin D
2
and vitamin D
3
in all forms (powders, ready-to-feed liquids, and liquid
concentrates) of infant, adult, and pediatric nutritional formulas. For the purpose of this SMPR, vitamin D2 is
defined as ergocalciferol (CAS 8017-28-5) and its previtamin isomer; and vitamin D3 is defined as
cholecalciferol (CAS 67-97-0) and its previtamin isomer
(3)
The method has been demonstrated to be suitable for the analysis of vitamin D in a wide range of infant
formulas and nutritional products, as illustrated with the range of different matrices used in this collaborative
study.
Safety Considerations
There are no major hazards beyond those typically found in chemistry laboratories. Use appropriate safety
equipment when handling acids, bases, and solvents. Refer to MSD sheets for detailed safety instructions
for each chemical used.
Comments from Collaborators
A summary of each laboratory’s performance was sent to participants along with an invitation to make
comments on the performance of the method in their laboratory. The following comments were received:
2016.05 (FEBRUARY 2017) VITD-18
MLT REPORT
FOR ERP USE ONLY
DO NOT DISTRIBUTE