P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
1503
Table 19. SLVstudy: accuracy, precision, andHorRat values found for zinc 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
Sterilizedcream
Zn
h
3.1±0.2
2.6±0.6
83±7
0.05
0.4
0.60
16.9
22.5
1.6
Zn
i
2.7±0.6
88±7
0.14
0.5
0.50
16.7
19.3
1.4
Zn
i
2.6±0.7
82±8
0.05
0.4
0.60
16.8
23.3
1.7
Cornbran
Zn
h
18.6±1.1
17.6±1.3
95±6
0.38
0.8
2.1
1.8
4.5
0.4
Zn
i
17.8±1.4
96±6
0.50
0.2
0.9
1.2
5.0
0.4
Zn
i
17.5±1.3
94±6
0.35
0.2
0.7
1.4
4.3
0.4
Dieteticmilkpowder 1
Zn
h
74.8±0.6
72.8±1.4
97±1
0.02
0.5
0.6
0.6
0.9
0.1
Zn
i
73.9±1.7
99±1
0.24
0.8
1.6
1.1
2.1
0.3
Zn
i
72.7±1.3
97±1
0.01
0.5
0.5
0.7
0.7
0.1
Nonfatmilkpowder
Zn
h
46.1±1.1
45.6±2.4
99±3
0.68
0.8
2.1
1.8
4.5
0.5
Zn
i
44.1±2.4
96±3
0.14
0.8
2.1
1.8
4.7
0.5
Zn
i
45.2±2.1
98±3
0.51
0.8
1.8
1.7
3.9
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
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