AOAC ERP Gluten Assays - Dec 2018

Annex B

4.1.7.3 Trueness To characterize for traceability, the reference materials mentioned in AOAC SMPR ® 2017.021 (see chapter 3.4 Reference Materials) were analyzed with 10 replicates in three different lots (tables 10 to 12). The analysis of the blank oat flour material shows, that for blank oat-based samples, RIDASCREEN ® Total Gluten can measure concentrations below 1 mg/kg gluten, excluding a potential cross reactivity to oats.

Table 10. Analysis of the blank Reference Materials mentioned in AOAC SMPR ® 2017.021 to characterize the RIDASCREEN ® Total Gluten for trueness; 10 replicates in three different lots.

Lot 1

Lot 2

Lot 3

mg/kg

mg/kg

mg/kg

< Std 1 < Std 1 < Std 1 < Std 1 < Std 1 < Std 1 < Std 1 < Std 1 < Std 1 < Std 1

0,82 0,33 0,28 0,43 0,59 0,24 2,66 1,07 5,62

0,74 1,32 0,30 0,34 1,04

< Std 1

< Std 1

0,65 0,85

< Std 1

0,15

Table 11 summarizes results from the analysis of the materials that were contaminated at 10 mg/kg gluten from wheat, rye, or barley. Depending on the lot that was used for the experiment, recoveries from 97% up to 115% were found for wheat contaminated oat flour while for barley materials the recoveries were somewhat higher between 103% and 131%. The highest recoveries between 150% and 174% were found for the rye contaminated oat flour.

Table 11. Analysis of the oat Reference Materials mentioned in AOAC SMPR ® 2017.021 to characterize the RIDASCREEN ® Total Gluten for trueness at a gluten level of 10 mg/kg; 10 replicates in three different lots.

Lot 1

Lot 2

Lot 3

mg/kg

mg/kg

mg/kg

11.9

8.3

11.2

11.2 7.87 7.51 11.4 10.9 10.8 9.54 10.9 12.8 10.5 105 1.69 16.1

11.1 8.11 7.25 10.7 10.8 10.0 8.40 10.7 11.9

11.9 9.52 8.93 12.8 12.7 12.0 10.7 12.1 13.2 11.5 115 1.42 12.3

Wheat in oat 10 mg/kg

Mean

9.7

97

Mean rec. [%]

SD

1.58 16.3

CV [%]

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RIDASCREEN ® Total Gluten In-house validation report 2018-10-21