2
repeatability standard deviation (SD
r
); or % repeatability relative standard deviation
48
(%RSD
r
).
49
50
Reproducibility
51
The standard deviation or relative standard deviation calculated from among-laboratory
52
data. Expressed as the reproducibility relative standard deviation (SD
R
); or % reproducibility
53
relative standard deviation (% RSD
R
).
54
55
Vitamin B
3
(Niacin)
56
Niacin (vitamin B
3
) refers to two compounds: Nicotinic Acid and Nicotinamide. Both forms of
57
the vitamin are equally biological active. Nicotinic acid is chemically pyridine 3-carboxylic
58
acid, CAS Registry Number: 59-67-6. Nicotinamide is pyridine 3-carboxcylic acid amide, CAS
59
Registry Number: 99586-65-9. See figure 1.
60
61
62
Figure 1: Chemical structure of components of niacin.
63
64
4.
Method Performance Requirements:
65
Analytical range
100 – 1100*
Limit of Quantitation (LOQ)
≤ 100*
Accuracy
± 20%
Repeatability (RSD
r
)
≤ 14%
Reproducibility (RSD
R
)
≤ 20%
Concentrations apply to: a) ‘ready-to-feed” liquids “as is”; b) re-
constituted powders (25 g into 200 g of water); and c) liquid
concentrates diluted 1:1 by weight.
*μg /100 g reconstituted final product.
66
67
68
5.
System suitability tests and/or analytical quality control:
69
Suitable methods will include blank check samples, and check standards at the lowest point
70
and midrange point of the analytical range.
71
72
6. Reference Material(s):
73
NIST Standard Reference Material
®
1849a; Infant/Adult Nutritional Formula or equivalent.
74
The SRM is a milk-based, hybrid infant/adult nutritional powder prepared by a manufacturer
75
of infant formula and adult nutritional products. A unit of SRM 1849 consists of 10 packets,
76
each containing approximately 10 g of material. Certified value of NIST1849a is 109
±
10
77
mg/Kg of niacin.
78
79
