© 2013AOAC INTERNATIONAL
correctedbyone recommendedwavelength for appropriate internal
standard. All responses for both recommended and alternative
wavelengths for each element are correctedusingonlyone internal
standard line. The following is a list of wavelengths for each
element (and its appropriate internal standard) inpriorityorder that
have been found acceptable formain foodstuffs:Wavelength (nm):
Ca: 317.933 (In: 303.936); Cu: 324.754 (In: 303.936); Fe: 259.94
(Sr:338.071);K:766.491(Sr:460.733);Mg:285.213(In:303.936);
Mn: 257.610 (Sr: 338.071);Na: 589.592 (Sr: 460.733); P: 213.618
(In: 303.936); Zn: 213.857 (Sr: 338.071).
Other wavelengths that are acceptable for both elements and
internal standards could be used as confirmatory analytical lines
or alternative wavelengths as certain recommended lines may not
be available on some ICP-OES systems: Wavelength (nm): Ca:
317.933 (Y: 371.028); Cu: 324.754 (Y: 371.028), 327.395 (In:
salted food rawmaterials (e.g., culinary products or tastemakers)
and a minimum of 500 mg/kg cesium (for main food samples);
20mg/kg indium and 5mg/kg strontium, yttrium, and chromium;
less than half of each element concentration of the higher working
standardStd6 and less than 0.5 g/kg total dissolvedminerals.
Powersettingsandnebulizergasflowmustbeoptimized toensure
that theMg280.271:Mg285.213 ratio (Mermet principle of robust
plasma) demonstrates robust operating conditions in accordance
with the ratio established by the instrument manufacturer.At least
three replicate readings of the same sample are performed, with
relatively long integration times tominimize noise.
(
b
)
ICP wavelengths
.
____
A number of recommended and
alternative wavelengths may be used for the nine elements to
be determined and internal standards. As a minimum, select one
recommended and one alternative wavelength for each element
Table 2011.14H. Interlaboratory study results for phosphorus
Matrix
Mean, mg/kg Rec.,% S
r
a
RSD
r
b
,% S
R
c
, ng/g RSD
R
d
,% HorRat
No. of labs
e
Outlier labs
f
Chocolatemilk powder
4138.12
101 84.53
2.04
115.22
2.78
0.61
9
NS
g
Dieteticmilk powder 2
3729.50
100 46.37
1.24
101.72
2.73
0.59
9
NS
Infant cereal
4341.81
101 60.56
1.39
111.79
2.57
0.57
9
NS
Peanut butter NISTSRM2387 3444.06
(3378)
h
102 98.10
2.85
111.97
3.25
0.69
9
NS
Wheat glutenNISTRM 8418
2050.02
(2190)
h
94
37.86
1.85
67.15
3.28
0.65
9
NS
a
S
r
=Standarddeviation for repeatability (within laboratory).
b
RSD
r
=
Relative standard deviation for repeatability.
c
S
R
=Standarddeviation for reproducibility (among laboratories).
d
RSD
R
=Relative standard deviation for reproducibility.
e
Reporting laboratoriesminus outliers.
f
C=Cochran outlier; SG=SingleGrubbs outlier; DG=DoubleGrubbs outlier.
g
NS=Not significant.
h
Value in parentheses =Certified or reference values.
Table 2011.14I. Interlaboratory study results for zinc
Matrix
Mean, mg/kg Rec.,% S
r
a
RSD
r
b
,% S
R
c
, ng/g RSD
R
d
,% HorRat
No. of labs
e
Outlier labs
f
Chocolatemilk powder
18.06
NA
h
0.396
2.19
0.95
5.24
0.51
8
5SG
Dieteticmilk powder 2
53.65
105
1.43
2.66
2.36
4.40
0.50
9
NS
Infant cereal
36.51
NA 0.92
2.25
1.27
3.44
0.37
9
NS
Peanut butter NISTSRM 2387 26.64
(26.3)
i
101
1.06
3.96
1.78
6.69
0.69
9
NS
Wheat glutenNISTRM 8418
49.30
(53.8)
i
92
0.96
1.95
3.19
6.46
0.73
9
NS
a
S
r
=Standarddeviation for repeatability (within laboratory).
b
RSD
r
=
Relative standard deviation for repeatability.
c
S
R
=Standarddeviation for reproducibility (among laboratories).
d
RSD
R
=Relative standard deviation for reproducibility.
e
Reporting laboratoriesminus outliers.
f
C=Cochran outlier; SG=SingleGrubbs outlier; DG=DoubleGrubbs outlier.
g
NS=Not significant.
h
NA=Not available.
i
Value in parentheses =Certified or reference values.
MTE-01
FORWORKINGGROUP/ERPUSEONLY
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