AOAC-RI ERP Book - Gluten.pdf

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

Mean

Mean

Mean

SD

SD

SD

SD

9.8

9.5

9.8

9.7

Control 1 Control 2 Control 3

0.43 0.73 0.16

0.70 0.53 0.14

0.54 0.87 0.69

0.48 1.29 0.38

15.1

15.1

15.0

15.4

4.0

4.4

4.1

4.2

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.

Exchange ofthimerosal

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