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J
ournal of
AOAC I
nternational
V
ol.
98, N
o.
5, 2015
Table 4. Method efficiency for the determination of 20 pesticides in fortified tea samples by GC/MS (16 laboratories)
Green tea
Oolong tea
Avg. C., μg/kg
Rec., %
Avg. C., μg/kg
Rec., %
No.
Pesticide
No. of
labs No. 1 No. 2
Avg. C.,
μg/kg No. 1 No. 2
Avg.
rec., %
S
r
,
μg/kg
RSD
r
,
%
S
R
,
μg/kg RSD
R
, % HorRat
No. of
labs No.6 No.7
Avg. C.,,
μg/kg No.6 No.7
Avg. rec.,
%
S
r
,
μg/kg RSD
r
, %
S
R
,
μg/kg RSD
R
, % HorRat
1
Trifluralin
15 186.7 180.1 184.6 93.4 90.0 91.7 8.3 4.5 15.4
8.4
0.4
16 85.6 85.8 85.7 85.6 85.8 85.7 2.4 2.8
19.0
22.2
1.0
2
Tefluthrin
16 93.4 92.0 92.7 93.4 92.0 92.7 3.5 3.8 9.1
9.8
0.4
16 42.9 42.8 42.8 85.7 85.6 85.6 1.7 4.0
7.3
17.0
0.7
3
Pyrimethanil
16 90.8 89.9 90.3 90.8 89.9 90.3 2.5 2.7 7.9
8.8
0.4
16 41.7 42.3 42.0 83.4 84.5 83.9 1.7 3.9
8.7
20.7
0.8
4
Propyzamide 16 95.4 95.0 95.2 95.4 95.0 95.2 4.0 4.2 8.1
8.5
0.4
14 46.0 45.1 45.1 92.0 90.2 91.1 1.4 3.2
6.9
15.3
0.6
5
Pirimicarb
15 92.4 92.3 92.4 92.4 92.3 92.4 2.6 2.8 9.1
9.9
0.4
13 44.6 43.2 44.6 89.3 86.4 87.8 2.1 4.6
8.3
18.6
0.7
6
Dimethenamid 16 37.5 37.5 37.5 93.8 93.6 93.7 1.2 3.1 3.0
7.9
0.3
16 17.6 17.0 17.3 88.1 85.0 86.6 1.4 7.8
3.6
20.9
0.7
7
Fenchlorphos 16 175.7 175.0 175.3 87.8 87.5 87.7 5.7 3.2 13.4
7.6
0.4
16 82.1 79.8 81.0 82.1 79.8 81.0 5.0 6.2
14.4
17.8
0.8
8
Tolclofos-methyl
14 92.5 92.6 92.7 92.5 92.6 92.5 2.5 2.7 6.1
6.5
0.3
14 44.7 42.7 44.1 89.5 85.4 87.4 2.8 6.5
5.5
12.5
0.5
9
Pirimiphos-methyl
16 94.0 93.1 93.5 94.0 93.1 93.5 2.9 3.1 6.4
6.9
0.3
16 42.8 41.7 42.2 85.5 83.4 84.5 2.8 6.7
7.6
18.0
0.7
10
2,4
'
-DDE 16 372.1 371.2 371.7 93.0 92.8 92.9 10.4 2.8 34.3
9.2
0.5
16 174.0 171.9 172.9 87.0 85.9 86.5 5.2 3.0
28.9
16.7
0.8
11 Bromophos-ethyl
16 92.8 92.3 92.6 92.8 92.3 92.6 2.3 2.5 7.2
7.8
0.3
16 43.7 43.7 43.7 87.4 87.4 87.4 1.7 3.9
9.3
21.3
0.8
12
4,4
'
-DDE 16 373.0 373.0 373.0 93.3 93.3 93.3 10.9 2.9 31.8
8.5
0.5
16 171.7 170.8 171.3 85.9 85.4 85.6 5.8 3.4
34.1
19.9
1.0
13
Procymidone 15 94.3 94.3 94.1 94.3 94.3 94.3 1.9 2.1 8.0
8.5
0.4
16 45.0 43.9 44.5 90.0 87.8 88.9 3.0 6.7
8.3
18.6
0.7
14
Picoxystrobin 16 191.7 192.2 191.9 95.8 96.1 96.0 6.4 3.4 15.3
7.9
0.4
15 90.4 88.4 88.9 90.4 88.4 89.4 3.4 3.8
12.3
13.8
0.6
15
Quinoxyfen 15 90.8 91.8 91.3 90.8 91.8 91.3 4.4 4.9 8.4
9.2
0.4
16 43.2 43.4 43.3 86.4 86.8 86.6 2.7 6.2
10.7
24.8
1.0
16
Chlorfenapyr
16 764.2 754.9 759.6 95.5 94.4 94.9 21.9 2.9 61.1
8.0
0.5
16 333.2 338.2 335.7 83.3 84.6 83.9 22.5 6.7
84.0
25.0
1.3
17
Benalaxyl
15 93.7 95.4 94.1 93.7 95.4 94.6 4.5 4.8 8.0
8.5
0.4
13 42.9 44.8 43.6 85.9 89.7 87.8 2.9 6.6
5.8
13.4
0.5
18
Bifenthrin
15 94.7 95.2 95.1 94.7 95.2 94.9 2.8 2.9 8.7
9.2
0.4
15 45.7 45.3 45.5 91.3 90.6 91.0 3.3 7.2
8.5
18.6
0.7
19
Diflufenican 15 94.4 94.3 94.5 94.4 94.3 94.4 3.4 3.6 8.1
8.6
0.4
15 43.4 42.6 43.4 86.7 85.3 86.0 2.4 5.4
6.4
14.8
0.6
20 Bromopropylate 15 189.5 190.1 190.2 94.8 95.1 94.9 5.4 2.9 15.1
7.9
0.4
16 88.0 87.1 87.6 88.0 87.1 87.6 5.9 6.7
12.3
14.1
0.6