AOAC-RI ERP Book - Gluten.pdf

3.4 RIDASCREEN ® Gliadin competitive R7021 (OMA first action 2015.05)

3.4.1 Results

The original raw data (obtained OD values for the standards and control samples) are presented in the annex section 7.4.1. From these data, the concentrations of the controls samples were calculated for each measurement using thimerosal or bronidox L containing wash buffer as shown in table 7. Table 7 : calculated concentrations of the control samples in mg/kg gliadin.

Stored buffer

Start

Storage as 10 fold concentrate

Storage as finally diluted

Duration of storage Storage temperature

0 weeks

3 weeks

6 weeks

3 weeks

6 weeks

NA

4°C

37°C

4°C

37°C

4°C

37°C

4°C

37°C

Thimerosal

Control 1 Control 2 Control 3 Control 1 Control 2 Control 3

<5

<5

<5

<5

<5

<5

<5

<5

<5

7.50

10.02 20.47

18.60 27.01

12.43 21.75

7.30

10.09 25.19

12.65 24.80

8.64

6.11

23.50

19.08

20.21

16.94

Bronidox L

<5

<5

<5

<5

<5

<5

<5

<5

<5

8.26

8.21

11.24 25.13

5.80

5.20

11.59 32.97

13.42 30.44

5.14

6.56

23.04

24.20

20.03

20.42

16.49

23.86

3.4.2 Evaluation

The obtained values for Gliadin competitive were evaluated in the same way as the obtained values for FAST Milk, see section 3.1.2. The results are shown in table 8. Table 8: calculated mean concentrations and standard deviations (SD) of the control samples in mg/kg gliadin.

Stored buffer

Thimerosal

Bronidox L

Storage temperature

4°C

37°C

4°C

37°C

Mean

Mean

Mean

Mean

SD NA

SD NA

SD NA

SD NA

NA

NA

NA 7.7

NA 9.1

Control 1 Control 2 Control 3

10.3 21.9

11.2 22.0

1.57 2.29

5.71 4.73

2.92 7.10

3.87 4.16

23.4

25.0

In contrast to the other three ELISA, the relative standard deviations are quite high with a mean coefficient of variation (CV) of 28.2% (calculation not shown). Therefore, this mean CV was compared

Exchange ofthimerosal

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