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Exchange ofthimerosal
Page 4
3.1.2
Evaluation
In order to assess whether the substitution of thimerosal by bronidox L leads to significant changes of
the stability and the functional abilities of the test, the calculated concentrations were compared
with each other. For this purpose, mean concentrations and standard deviations of the two buffers
stored at 4°C and at 37°C were calculated from the data shown in table 1. Means and standard
deviations were calculated of the four measurements at 4°C and at 37°C using the respective washing
buffer. The results are shown in table 2.
Table2:
calculated mean concentrations and standard deviations (SD) of the control samples in mg/kg
milk protein.
Stored
buffer
Thimerosal
Bronidox L
Storage
temperature
4°C
37°C
4°C
37°C
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Control 1
9.8
0.43
9.5
0.70
9.8
0.54
9.7
0.48
Control 2
15.1
0.73
15.1
0.53
15.0
0.87
15.4
1.29
Control 3
4.0
0.16
4.4
0.14
4.1
0.69
4.2
0.38
3.1.3
Discussion
As shown in table 2, the calculated mean concentrations were extremely similar to each other,
regardless of the used washing buffer and of the storage temperature of the washing buffer. The
small differences in mean concentrations lie well within standard deviations. This demonstrates that
the change of washing buffer does not have a significant influence on the concentrations of the
control samples and thus on the functionality of the test.
Furthermore, the stability of the washing buffer has been demonstrated in an accelerated stability
testing with 6 weeks at 37°C, which is more than the usually applied maximum of 4 weeks at 37°C. As
also shown in table 2, mean concentrations at 4°C and 37°C are extremely similar to each other,
demonstrating that the stability of the washing buffer is not affected by the substitution of the
preserving agent.