1504
P
OITEVINETAL.
: J
OURNALOF
AOACI
NTERNATIONAL
V
OL
. 92,N
O
. 5, 2009
Table 20. MD1–4 ruggedness tests: accuracy, precision, andHorRat values found for calciuminsixcertifiedand in-house referencematerialsusing
recommended lines
Material description
-test code
a
Reference
value,mg/kg
b,c
Median,
mg/kg
Recovery,%
P
-value
d
SD
r
,mg/kg
e
SD
iR
,mg/kg
f
RSD
r
,% RSD
iR
,% HorRat
g
Chocolatemilkpowder
MD1
9870±124
9915
100±1
0.92
91
171
0.9
1.7
0.3
MD2
9913
100±2
0.93
97
250
1.0
2.5
0.4
MD3
9697
98±1
0.20
155
250
1.6
2.6
0.5
MD4
10042
101±2
0.36
68
211
0.7
2.1
0.4
Infant cereals
MD1
6000±44
6752
113±3
0.003
337
526
5.0
7.7
0.8
MD2
6027
100±1
0.80
111
270
1.8
4.4
0.5
MD3
5764
96±1
0.01
89
148
1.5
2.6
0.3
MD4
5731
96±2
0.03
158
277
2.8
4.8
0.3
Cornbran
MD1
420±19
374
89±6
0.09
13
46
3.3
12.2
1.3
MD2
405
96±6
0.55
7
44
1.6
11.0
1.2
MD3
411
98±5
0.71
4
37
1.1
8.9
1.0
MD4
313
75±5
0.002
9
51
2.8
16.1
1.7
Dieteticmilkpowder 1
MD1
3020±15
3062
101±1
0.07
33
43
1.1
1.4
0.2
MD2
3031
100±1
0.77
26
95
0.9
3.1
0.5
MD3
2958
98±2
0.23
30
130
1.0
4.4
0.7
MD4
2986
99±1
0.21
43
66
1.4
2.2
0.3
Pet food
MD1
6190±140
6365
103±2
0.29
83
144
1.3
2.3
0.4
MD2
6457
104±3
0.15
80
226
1.2
3.5
0.6
MD3
6198
100±3
0.96
151
251
2.4
4.1
0.7
MD4
6384
103±3
0.25
176
210
2.7
3.0
0.5
Nonfatmilkpowder
MD1
13000±250
13012
100±2
0.97
93
192
0.7
1.5
0.3
MD2
12931
100±2
0.81
170
377
1.3
2.9
0.5
MD3
12612
97±2
0.17
113
220
0.9
1.7
0.3
MD4
12845
99±2
0.57
157
257
1.2
2.0
0.4
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
