P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
1497
Table 13. SLVstudy: accuracy, precision, andHorRat values found for iron in four certifiedand in-house referencematerialsusing recommendedandalternate
lines
Material description
Line
Reference
value,mg/kg
a,b
Median±U,
mg/kg
c
Recovery,%
P
-value
d
SD
r
,mg/kg
e
SD
iR
,mg/kg
f
RSD
r
,% RSD
iR
,% HorRat
g
Chocolatemilkpowder
Fe
h
169.9±2.4 166.9±12.0
98±2
0.33
13.2
11.7
7.9
7.0
1.0
Fe
i
163.1±12.4
96±2
0.10
13.1
12.2
7.9
7.3
0.8
Fe
i
166.6±13.1
98±2
0.35
13.3
12.7
8.0
7.6
1.2
Infant cereals
Fe
h
80.4±0.6
79.6±1.3
99±1
0.28
1.0
1.1
1.2
1.4
1.0
Fe
i
79.0±1.2
98±1
0.09
1.0
1.1
1.3
1.3
0.7
Fe
i
79.5±1.3
99±1
0.25
1.1
1.2
1.3
1.4
0.3
Cornbran
Fe
h
14.8±0.9
14.7±1.3
99±6
0.88
0.2
1.0
1.3
6.7
0.2
Fe
i
14.7±1.2
99±6
0.92
0.2
0.8
1.3
5.4
0.3
Fe
i
14.7±1.1
99±6
0.88
0.2
0.7
1.4
4.8
0.3
Dieteticmilkpowder 1
Fe
h
58.5±0.4
59.3±0.9
101±1
0.11
0.8
0.8
1.3
1.3
0.2
Fe
i
59.1±0.9
101±1
0.24
0.7
0.8
1.1
1.4
0.3
Fe
i
59.1±1.0
101±1
0.26
0.7
0.9
1.1
1.5
0.4
a
SDexpressedashalf of stateduncertainty (NISTandLGCcertifiedmaterials) givenas95%confidence interval.
b
SDexpressedasa reproducibilitySD(in-house referencematerials) calculatedaccording to robust statistics (29).
c
Uncertainty (U) estimated throughsimplifiedapproach (30, 31).
d
Statisticevaluationof robust
t
-test: Satisfactory result (
P
>0.05); questionable result (0.01<
P
<0.05); unsatisfactory result (
P
<0.01).
e
SD
r
=SDof repeatability.
f
SD
iR
=SDof intermediate reproducibility.
g
HorRat =RatiousingRSD
iR
andHorwitzdenominator according to ref. 32.
h
Recommended line for ICP-AESanalysis.
i
Alternateconfirmatory lines for ICP-AESanalysis.
MTE-01
FORWORKINGGROUP/ERPUSEONLY
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