OMA Consulting Protocol Review: OMACON-2019-2

2018.009 identifies three separate analytical ranges, dependent on the type of product evaluated: 5-100 mg/100g for infant formula and adult nutritionals; 10-100 mg/100g for lactose free milk, milk products and products containing dairy ingredients; >100-2,000 mg/100g for low-lactose milk, milk products and products containing dairy ingredients. 2.5.1 A stock solution of 4g/L of D-Lactose monohydrate, CAS Number: 64044- 51-5, ≥99%) in LAC Measurement Solution containing 23 g/L of glucose will be prepared to make the specified lactose standards. (0.2 g D-Lactose monohydrate and 1.15 g D-Glucose anhydrous in 50 mL LAC Measurement Solution) 2.5.1.1 For the 0-200 mg/L calibration range the following concentrations will be prepared: 0, 25, 50, 75, 100, 125, 150, 175 and 200 mg/L. 2.5.1.2 For the 0-2 g/L calibration range the following concentrations will be prepared: 0, 10, 25, 50, 75, 1,00, 125, 150, 175 and 200 mg/L. 2.5.1.3 For the 0-6 g/L calibration range the following concentrations will be prepared: 0, 25, 75, 1,50, 225, 3,00, 375, 450, 424 and 600 mg/L. Note* For the 0 - 2 g/L and 0 - 6 g/L range, the sample is diluted 1/10 prior to analysis so a calibration range of 0-200 mg/L and 0 – 600 mg/L is used. 2.5.2 Test a minimum of 2 replicates at each concentration and randomize and blind code the samples. 2.5.3 Perform the assay according to the candidate method instructions for use (Section 2.4 or Appendix 1) on the samples. Testing will be performed following instructions for milk. 2.5.4 If a sample is above the measurement range, follow method instructions for re-analysis. 2.5.5 Plot results vs. concentration and analyse for linearity. 2.5.6 Plot residuals vs. concentration and look for non-random patterns. 2.5.6.1 If a non-random pattern is discovered, find a model to reduce or eliminate it. 2.5.6.2 Repeat the linearity and residual analyses with the new model.

Interference and Cross Reactivity

2.4

Interference studies will be conducted in lactose free milk to evaluate both positive and negative interferences of the method. Compounds will include different monosaccharides and disaccharides (in order to test cross reactivity of

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