6. AOACSPIFANMethods-2018Awards

335

where w induced glycidol-d5

= quantity of induced glycidol-d 5

, in µg/kg x sample; w glycidol-Tf = peak area of induced glycidol-d 5

= quantity of glycidol

in Tf sample, in µg/kg x sample; PA induced glycidol - d5

(via 3-MBPD-d 5

- PBA

derivative); PA glycidol

= peak area of glycidol in Tf sample (via 3-MBPD - PBA derivative).

w

5 d cidol

3 inducedgly w −

−

Tf

=

5

d MCPD −

where Tf = transformation factor; w induced glycidol-d5

= quantity of induced glycidol-d 5

, in µg/kg x sample; w 3-

MCPD-d5 , in µg/kg × sample. In order to calculate the accurate glycidol concentration, each raw glycidol value is corrected using the following calculation: w Glycidol = w raw glycidol value – ( w 3-MCPD x TF) where w Glycidol = quantity of corrected glycidol in µg/kg × sample; w raw glycidol value = quantity of uncorrected (raw) glycidol in µg/kg × sample; Tf = transformation factor. G. Reporting The method is applicable for the determination of free 2-MCPD, bound 2-MCPD, free 3-MCPD, bound 3- MCPD and bound glycidol. The overall (total) contents of 2-MCPD and 3-MCPD can be reported by adding together the concentrations of the free and bound analytes. For this reason, all results should indicate whether the concentrations correspond to the free, bound or overall analyte contents. The terms “free” and “bound” are used to differentiate whether the analyte was present as a single, “free" compound that did not undergo any chemical transformation in the original sample, or if the analyte was originally ester- linked, or “bound”, to various fatty acids (and to a minor extent other chemical groups) in the original sample. Because this method includes an ester-cleavage step, the molecular weights of the fatty acids do not contribute to the determined values of the bound analytes. Additionally, results for bound analytes cannot be reported as MCPD ester or glycidyl ester concentrations using this method. Analyte contents are reported in µg/kg of product. If calculations are not performed as specified in F and the analyte concentrations are reported on the basis of the extracted oil phase this must be clearly indicated. References: J. AOAC Int . (future issue) AOAC SMPR 2017.017 (MCPD) J. AOAC Int . 101 , 324(2018) DOI: 10.5740/jaoacint.SMPR2017.017 Posted: January 29, 2019 = quantity of 3-MCPD-d 5