OMA Protocol Review: OMAMAN-56 Sulfites in Shrimp
dissolving 66.1 mg of formaldehyde sodium bisulfite adduct (CAS 870-72-4, MW 134.09 g/mol) in 10 mL
of Extraction Solution. The following working solutions were prepared from this stock solution: 0, 2, 5, 8,
These solutions were prepared fresh at the time of analysis and kept at
10, 12, 15, 30 and 50 mg/L of SO 2.
room temperature during the assay. All solutions were analyzed on the same day by the same technician
with the same BIOFISH 300 device according to the Determination step detailed above.
( b ) Results.-- The linearity and residual plot results are presented in Table 1 and Figure 6. Although the linearity was tested over a larger range than the one claimed, the results show a linear
response from 0 to 50 mg/L, with a correlation coefficient r≥0.999. This means that a loss in activity of the
Biotest will not result in a reduction in the linear range of the method. From 5 to 30 mg/L all the residuals
are less than 10%, demonstrating once again the high lineal tendency of the response.
Table 1. Method developer linearity results of the BIOFISH 300 SUL
Sulfite Standard (mg/L)
BIOFISH 300 SUL (mg/kg)
MEAN (mg/kg)
Residual (%)
S r
RSD r
(%)
0
0.19
0.27
0.17
0.21
0.05
25.20
2
1.73
1.95
1.81
1.83
0.11
6.08
-20.38
5
4.95
4.59
4.79
4.78
0.18
3.78
-7.92
8
7.43
7.31
7.58
7.44
0.14
1.82
-8.35
10
9.74
9.92
9.79
9.82
0.09
0.95
-2.48
12
11.56 11.74 11.91
11.74
0.18
1.49
-2.37
15
14.42 14.66 15.10
14.73
0.34
2.34
-1.53
30
30.36 30.60 30.21
30.39
0.20
0.65
2.53
50
50.58 50.82 50.61
50.67
0.13
0.26
2.94
15
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