AOAC Gluten Quantitative Validation Guidance-Round 1(Nov 2023)

Overall mean

x

0.04

0.612

0.882

2.395

Intermediate precision standard deviation

S i

0.108

0.211

0.22

0.305

Intermediate precision relative standard deviation

%RSD i

273.438

34.456

24.888

12.721

272 273

Example Data

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

y = 0.0755x + 0.1368 R² = 0.8857

Deviation

0

0.5

1

1.5

2

2.5

3

Intermediate Precision Standard

Mean Observed Concentration (ppm)

= ( ̅ ( 0 ) +3.3× ( 0 ) ) (1 − 1.65× ) = ( ( 0 1 .04+3.3×0.1368) − 1.65 × 0.0755) = 0.56

274 275 276 277 278 279

Limit of Quantification (LOQ) 280 Data required: mean concentration and intermediate precision standard deviation values from above, 281 linear regression for S i vs. concentration 282 Model %RSD i across a range of concentrations below and above the expected LOQ using linear 283 regression and S i(0) above

284 285 286 287 288 289

Linear Regression: = × + ( 0 ) %RSD i Modeling: % =100× ( × + ( 0 ) )

Plot %RSD i vs. mean concentration 290 Estimate LOQ by calculating the concentration at which %RSD i would meet acceptable levels (e.g., 291 maximum %RSD i prescribed in an SMPR). The estimated LOQ must also be greater than the estimated 292 LOD. 293