MCPD-02 Reviewer Forms (July 19, 2018)

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Reviewer 7

• Variability of fat extraction related to matrix composition not addressed. Addressed in revised method.

Supporting Data • General Comment: - Method Optimization: Appears that steps were taken to determine ranges for time critical and temperature critical steps which is very helpful. - Provides example chromatogram and linear range plot, which are helpful. - All data presented met SMPR guidance – no outliers

• Performance Characteristics:

Analytical Range: linearity was determined based on serial dilution of incurred samples for bound analytes and fortifications of free analytes in applicable matrices. Assumed that levels in incurred samples were determined with this procedure as I saw no other mention of how the reference levels were obtained. Concentration ranges tested covered the required analytical range.

Analyte

Range (µg/kg) Powdered IF

Range (µg/kg) Liquid IF

Free 2-MCPD Free 3-MCPD Bound 2-MCPD Bound 3-MCPD Bound Glycidol

5-275

0-120 0-120

0.8 - 275

0-557 0-1330 0-476

0-32 0-84 0-41

LOQ: Determined through S/N assessment of samples containing low levels of the analyte since blank assessment was found to be difficult.

Analyte

LOQ Powdered IF (µg/kg)

LOQ Liquid IF (µg/kg)

Free 2-MCPD Free 3-MCPD Bound 2-MCPD Bound 3-MCPD Total 2-MCPD Total 3-MCPD Bound Glycidol

5 5

1 1 2 2 3 3 2

10 10 15 15 10

Accuracy/Recovery: Determined utilized spiking as well as dilution of incurred samples. Results ranged from 93-109% for all testing across matrices and analytes. Measured values of reference materials within 92-104% of assigned values across analytes.

Precision (RSD r

): Ranged from 2.3-12%, depending on the analyte for powdered infant formula and

1.2 – 11% for liquid formula.

3