MCPD-02 Reviewer Forms (July 19, 2018)

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Reviewer 3

Method Safety Concerns:

None other than related to the routine handling of a variety of volatile and flammable solvents.

Pros/Strengths: • For powders one single extraction procedure is used for the combined extraction of free and bound (esterified) analytes. This is significant because most samples encountered in routine analysis are powders. • Quantitation is performed by one-point internal calibration. This greatly reduces the analyst’s workload because calibration curves don’t have to be generated with each sample set. • Internal standards are added at the beginning (before extraction), so the most benefit is derived from their use. • A standard GC/MS instrument is used, which is widely available in most laboratories. Cons/Weaknesses • A separate extraction procedure is needed for liquid samples. However, options have been provided to convert liquid samples to powders and vice versa to allow the use of a single extraction protocol. • Quantitation is complicated by the mathematical correction of the result for glycidol and the necessity to determine the transformation factor of 3-MCPD to glycidol with each sample set.

Supporting Data

• General Comment: the supporting data is sufficient.

Validation has been done to exceptional standards. Original and ingenuous matrix-matching scheme has been devised and implemented. Novel and valuable data is being presented on the crossover of free and bound analyte forms between their respective assays.

- Method Optimization: the method is presented in its final, optimized form.

• Performance Characteristics:

Analytical Range: 2-MCPD esters 10 – 557 µg/kg, 3-MCPD esters 10 – 1330 µg/kg, glycidyl esters 10 – 476 µg/kg, free 2-MCPD and free 3-MCPD 5 – 275 µg/kg (powders)

2-MCPD esters 2 – 32 µg/kg, 3-MCPD esters 2 – 84 µg/kg, glycidyl esters 2 – 41 µg/kg, free 2-MCPD and free 3-MCPD 1 – 120 µg/kg (liquids)

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