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

Values used as estimates of S i(0) should be the same as those used for the LOD calculations. 294 295 = ( 0 ) �� % 100 � � − � 296 297 Prepare an operator characteristic (OC) curve for LOQ 298

299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317

• Use a normal distribution calculation function to calculate the probability of obtaining a result higher than the LOQ for the given concentration using the calculated S i and assuming a normal • Normal distribution curves can be estimated in Excel with the following function, where LOQ is set at the estimate calculated above, S i is calculated according to the linear regression distribution.

• = 1 – NORMDIST(LOQ, mean concentration, S i , 1)

• Plot the probabilities versus concentration to prepare the OC curve.

Calculations/procedures for multiple matrices

• Model %RSD i across a range of concentrations (as described above) for all matrices together. It is generally expected that the relationship between %RSD i and concentration will be sufficiently similar across matrices to conduct a single analysis for the combined data from all matrices. • If the relationship between standard deviation and concentration appears to be substantially different between matrices, consult with the AOAC Statistics Committee and Expert Review

Panel.

Example Data and Calculations

Table 2: Example Data

Slope

0.0755 0.1368

Si(0)

318

Example Data

0 20 40 60 80 100

RSD(%)

0

1

2

3

4

RSD

RSD(Q)

319 320 321