1500
P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
Table 16. SLVstudy: accuracy, precision, andHorRat values found formanganese in threecertifiedand in-house referencematerialsusing recommendedand
alternate 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
Cornbran
Mn
h
2.55±0.15 2.33±0.18
91±6
0.15
0.03
0.12
1.1
4.9
0.4
Mn
i
2.55±0.25
100±6
0.96
0.03
0.20
1.1
7.3
0.5
Mn
i
2.39±0.17
94±6
0.25
0.03
0.09
1.1
3.6
0.3
Dieteticmilkpowder 1
Mn
h
12.7±0.85 12.8±1.1
102±7
0.83
0.27
0.68
2.1
5.3
0.5
Mn
i
13.4±1.3
105±7
0.48
0.26
0.88
2.0
6.6
0.6
Mn
i
12.8±1.1
101±7
0.88
0.24
0.67
1.8
5.2
0.5
Nonfatmilkpowder
Mn
h
0.26±0.03 0.22±0.03
85±10
0.16
0.01
0.02
3.1
6.8
0.3
Mn
i
0.20±0.03
79±9
0.06
0.01
0.02
3.8
10.8
0.5
Mn
i
0.22±0.03
85±10
0.08
0.01
0.01
3.6
5.9
0.3
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
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