RI-ERP-FINALACTION-Recommendations

OMAMAN-20 C/ In House Validation Report ERP Use Only - March 2015

4.1.4 Ruggedness Study The AOAC Appendix N does not describe any ruggedness testings when validating a qualitative method. Nevertheless, due to the fact that two AACC collaborative tests were already performed with this system, the ruggedness is included in variation of results from different participants. During a collaborative test the following parameters are varied in a range that occurs in a laboratory: person, temperature, time, and volumes. Since the outcome of both collaborative tests was excellent, the influence of these varying parameters in a lab should be small. Nevertheless, three parameters were tested for their ruggedness, (1) extraction time, (2) incubation time and (3) incubation temperature. By thoroughly mixing a naturally contaminated corn flour (2.4 mg gliadin/kg; RIDASCREEN® Gliadin R7001) with different amounts of a blank sample (approx. 0.3 mg gliadin/kg; RIDASCREEN® Gliadin R7001), very low assigned contamination levels were achieved. Using these samples for ethanol extraction and subsequently for dip-stick evaluation (n=10), it was revealed that there is no significant difference between the normal vortexing step of 30 s and an alternative step consisting of 30 s of vortexing followed by 10 min of mechanical shaking (table 4).

Table 4. Comparison of extraction times for the ethanol extraction step (30 s vortexing vs. 30 s vortexing plus 10 min shaking); Naturally-contaminated corn flours with different assigned gliadin concentrations were used (10 repeats for each condition and concentration).

mg gliadin/kg extraction

result for each repeat

POD

- - - - -

- - - - -

- - - -

- - - -

-

30 s vortex

0,00

-

0,30

30 s vortex + 10 min shaking

- -

0,00

+

+ + + + + + + -

+ + + + + + + +

30 s vortex

0,70

+ + + + + + +

+ + + + + + +

- -

0,56

30 s vortex + 10 min shaking

0,80

+ + + + +

30 s vortex

1,00

0,83

30 s vortex + 10 min shaking

1,00

AOAC Research Institute Expert Review Panel Use Only

For testing of robustness for the incubation time and temperature it was not necessary to use naturally contaminated samples. Therefore, a blank rice meal was spiked with different amounts of WGPAT gliadin to obtain concentrations of 0.5 mg gliadin/kg up to 2 mg gliadin/kg. All components used for extraction and dip-stick analysis were brought to the respective temperatures prior to extraction and analysis. Thus, a complete change in laboratory temperature was simulated. Using these samples for ethanol extraction and subsequently for dip-stick evaluation (n=10 for each variation), it was revealed that there is no significant influence of a change of temperature between 16°C and 30°C (table 5).

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RIDA®QUICK Gliadin Validation report 2015-01-14