1496
P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
Table 12. SLVstudy: accuracy, precision, andHorRat values found for copper 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
Cu
h
2.47±0.20 2.69±0.24
109±9
0.36
0.05
0.09
1.8
3.1
0.2
Cu
i
2.61±0.24
106±9
0.53
0.05
0.1
1.9
3.9
0.3
Cu
i
2.56±0.26
103±9
0.7
0.06
0.15
2.4
5.6
0.4
Cu
i
2.52±0.25
102±8
0.82
0.06
0.14
2.5
5.4
0.4
Dieteticmilkpowder 1
Cu
h
7.55±0.13 7.78±0.21
103±2
0.15
0.09
0.15
1.1
2
0.2
Cu
i
7.63±0.23
101±2
0.6
0.08
0.18
1
2.4
0.2
Cu
i
7.72±0.25
102±2
0.28
0.08
0.2
1
2.6
0.2
Cu
i
7.58±0.21
100±2
0.84
0.08
0.15
1
2
0.2
Nonfatmilkpowder
Cu
h
0.70±0.05 0.75±0.08
107±8
0.44
0.06
0.06
8.3
8.5
0.5
Cu
i
0.78±0.11
112±9
0.22
0.06
0.09
8.3
11.4
0.7
Cu
i
0.78±0.09
112±8
0.21
0.05
0.07
7
8.5
0.5
Cu
i
0.79±0.10
113±9
0.17
0.05
0.08
6.8
10.2
0.6
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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