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© 2015 AOAC INTERNATIONAL
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hexane.
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the silica deactivation,
see Note 4
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Notes 1
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volume to avoid sample breakthrough during the cleanup step.
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to the silica cartridge because it can affect the extract polarity,
thus potentially retention of fat and analytes on the silica gel. The
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only the isooctane and coextracted fat are left in the evaporation
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is
recommended for a better control of the evaporation process and
higher absolute recoveries of volatile PAHs.
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can vary, potentially resulting in different amounts of water in
the silica, thus its potentially different retention characteristics.
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fat and determine the optimum volume of the elution solvent to
ensure adequate analyte recoveries and fat cleanup. The following
procedure is recommended:
a
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of analyte responses in all tested fractions vs the elution volume.
See
Figure
2014.08B
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margin ensuring good analyte recoveries in routine practice. This
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cartridge tested in Figure
2014.08B
.
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for the example in Figure
2014.08B
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continued
PAH
No. of
laboratories No. of replicates
Mean
concn, μg/kg
Mean recovery,
%
s
r
, μg/kg s
R
, μg/kg RSD
r
, % RSD
R
, % HorRat
9
18
20.0
80.1
1.0
2.2
4.8
10.7
0.37
Naph
9
18
71.0
88.7
5.3
9.4
7.5
13.2
0.55
9
18
106.2
84.9
7.3
14.7
6.9
13.9
0.62
8
16
193.9
86.2
6.0
29.8
3.1
15.4
0.75
Phe
9
18
41.6
83.2
3.0
5.5
7.2
13.2
0.51
9
18
80.3
80.3
6.1
10.7
7.6
13.3
0.57
8
16
203.9
81.6
9.5
22.5
4.7
11.0
0.54
Pyr
9
18
34.0
85.1
2.2
3.3
6.4
9.8
0.37
8
16
63.2
84.3
2.2
5.3
3.5
8.4
0.35
9
18
163.4
81.7
8.0
16.6
4.9
10.2
0.48
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