1508
P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
Table 24. MD1–4 ruggedness tests: accuracy, precision, andHorRat values found formagnesiuminsixcertifiedand in-house referencematerialsusing
recommended lines
Material description
-test code
a
Referencevalue,
mg/kg
b,c
Median,mg/kg Recovery,%
P-
value
d
SDr,mg/kg
e
SD
iR
,mg/kg
f
RSD
r
,% RSD
iR
,% HorRat
g
Chocolatemilkpowder
MD1
1779±23
1782
100±2
0.93
19
42
1.0
2.4
0.3
MD2
1780
100±2
0.97
18
74
1.0
4.1
0.6
MD3
1789
101±1
0.69
24
25
1.3
1.4
0.2
MD4
1770
100±1
0.72
11
33
0.6
1.8
0.2
Infant cereals
MD1
881±8
827
94±1
0.002
28
32
3.4
3.9
0.5
MD2
898
102±2
0.29
17
37
1.9
4.1
0.5
MD3
922
105±1
0.004
21
22
2.2
2.4
0.3
MD4
893
101±1
0.33
19
26
2.1
2.9
0.4
Cornbran
MD1
818±30
778
95±3
0.20
9
11
1.1
1.4
0.2
MD2
749
92±3
0.04
14
16
1.8
2.1
0.3
MD3
778
95±4
0.21
7
15
1.0
1.9
0.2
MD4
761
93±3
0.08
5
9
0.7
1.2
0.1
Dieteticmilkpowder 1
MD1
1200±8
1191
99±1
0.21
13
17
1.1
1.5
0.2
MD2
1198
100±1
0.79
8
44
0.7
3.7
0.5
MD3
1216
101±1
0.21
5
17
0.4
1.4
0.2
MD4
1193
99±1
0.40
12
24
1.0
2.0
0.3
Pet food
MD1
48±2
462
96±3
0.17
7
8
1.5
1.8
0.2
MD2
474
99±3
0.67
4
14
0.9
3.0
0.3
MD3
472
98±3
0.55
6
12
1.3
2.5
0.3
MD4
456
95±3
0.12
7
21
1.5
4.6
0.5
Nonfatmilkpowder
MD1
1200±15
1188
99±1
0.51
13
25
1.1
2.1
0.3
MD2
1194
100±2
0.80
14
53
1.2
4.4
0.6
MD3
1185
99±1
0.37
9
16
0.8
1.3
0.2
MD4
1172
98±1
0.12
11
21
0.9
1.8
0.2
a
Ruggedness test usingdifferentmicrowavedigestionsystemsand ICP-AESequipment (Table1).
b
SDexpressedashalf of stateduncertainty (NISTandLGCcertifiedmaterials) givenas95%confidence interval.
c
SDexpressedasa reproducibilitySD(in-house referencematerials) calculatedaccording to robust statistics (29).
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.
MTE-01
FORWORKINGGROUP/ERPUSEONLY
DONOTDISTRIBUTE
