1506
P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
Table 22. MD1–4 ruggedness tests: accuracy, precision, andHorRat values found for iron in four certifiedand in-house referencematerialsusing recommended
lines
Material description
-test code
a
Reference
value,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
169.9±2.4
167.7
99±2
0.48
1.7
5.2
1.0
3.1
0.3
MD2
164.8
97±2
0.10
1.4
3.9
0.8
2.4
0.2
MD3
173.6
102±2
0.22
2.1
3.8
1.2
2.2
0.2
MD4
169.9
100±4
0.99
9.3
20.9
5.4
12.2
1.2
Infant cereals
MD1
80.4±0.6
79.9
99±2
0.72
3.0
3.8
3.7
4.7
0.4
MD2
77.8
97±1
0.02
1.8
2.0
2.3
2.6
0.2
MD3
77.7
97±2
0.05
1.3
2.7
1.7
3.5
0.3
MD4
72.8
91±2
0.005
3.2
5.5
4.3
7.5
0.6
Cornbran
MD1
14.8±0.9
12.5
85±7
0.05
0.3
1.8
2.6
13.8
0.9
MD2
13.9
94±6
0.31
0.9
0.9
6.2
6.1
0.4
MD3
12.4
84±6
0.03
0.4
1.3
2.8
10.7
0.7
MD4
10.7
72±6
0.002
0.5
1.7
4.9
15.9
1.0
Dieteticmilkpowder 1
MD1
58.5±0.4
58.0
99±1
0.51
0.9
1.8
1.5
3.2
0.3
MD2
57.6
98±1
0.24
0.7
1.8
1.2
3.1
0.3
MD3
57.8
99±1
0.31
1.0
1.8
1.8
3.2
0.3
MD4
56.3
96±1
0.10
0.9
1.6
1.6
2.9
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
