P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
1499
Table 15. SLVstudy: accuracy, precision, andHorRat values found formagnesiuminsevencertifiedand 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
Sterilizedcream
Mg
h
84.4±2.0
81.7±4.5
97±3
0.28
2.0
3.9
2.4
4.7
0.6
Mg
i
79.9±4.2
95±3
0.08
1.7
3.6
2.1
4.5
0.5
Mg
i
82.7±4.4
98±3
0.48
2.3
3.8
2.7
4.6
0.6
Chocolatemilkpowder
Mg
h
1779±23
1771±22
100±1
0.82
23
32
1.3
1.8
0.3
Mg
i
1757±67
99±2
0.48
22
59
1.3
3.4
0.7
Mg
i
1744±54
98±2
0.22
21
47
1.2
2.7
0.5
Infant cereals
Mg
h
881±8
911±46
103±2
0.10
25
43
2.7
4.7
0.8
Mg
i
902±43
102±2
0.22
21
40
2.3
4.5
0.8
Mg
i
892±48
101±2
0.53
24
46
2.7
5.1
0.9
Cornbran
Mg
h
818±30
791±45
97±4
0.53
9
35
1.1
4.4
0.8
Mg
i
775±45
95±4
0.25
8
33
1.0
4.2
0.7
Mg
i
785±40
96±4
0.41
9
26
1.1
3.3
0.6
Dieteticmilkpowder 1
Mg
h
1200±8
1206±25
101±1
0.88
8.0
23
0.7
1.9
0.3
Mg
i
1180±30
98±1
0.06
7.0
28
0.6
2.3
0.4
Mg
i
1181±34
98±1
0.03
9
29
0.8
2.5
0.5
Pet food
Mg
h
481±2
483±8
101±1
0.31
7
8
1.4
1.6
0.3
Mg
i
471±12
98±1
0.08
6
11
1.2
2.4
0.4
Mg
i
477±12
99±1
0.52
8
11
1.6
2.3
0.4
Nonfatmilkpowder
Mg
h
1200±15
1206±89
101±3
0.87
18
83
1.5
6.9
1.3
Mg
i
1186±70
99±2
0.60
19
65
1.6
5.5
1.0
Mg
i
1156±87
96±3
0.21
16
81
1.4
7.0
1.3
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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