AOAC SPIFAN Nutrients ERP-Final Review (Jan. 2019)

830 D RAHER & W HITE : J OURNAL OF AOAC I NTERNATIONAL V OL . 101, N O . 3, 2018

analyzed. As evidenced by the selection of this method as a First Action Official Method SM by the AOAC Expert Review Panel, it can be concluded that the method is suitable for the determination of Trp in infant formulas and pediatric/adult nutritional products.

Specificity

Typical standard SRM 1849a and enzyme blank chromatograms are provided below. No internal standard interference is present in the placebo, and the Trp peak area was found to be slightly below the average blank Trp area. A quantitative, duplicate analysis of the placebo sample gave a mean result of – 0.40 mg/100 g powder, which is equal to – 0.040 mg/100 g in the 25/225 reconstituted sample. This result is less than one-third the method LOQ as determined above and below the method LOD, representing no quantifiable Trp in the placebo powder. Chromatograms for all of the SPIFAN matrixes prepared without internal standard for chromatographic specificity showed no internal standard baseline interference for any of these matrixes.

Acknowledgments

We thank Jean Pan, Karen Schimpf, and Philip Haselberger for their guidance throughout the SLV submission process.

References

(1) Official Methods of Analysis (2016) 20th Ed., AOAC INTERNATIONAL, Rockville, MD, SMPR 2014.013 (2) Official Methods of Analysis (2005) 18th Ed., AOAC INTERNATIONAL, Gaithersburg, MD, Method 988.15 (3) Cevikkalp, S.A., Loker, G.B., Yaman, M., & Amoutzopoulos, B. (2016) Food Chem. 193 , 26 – 29 (4) Delgado-Andrade, C., Rufian-Henares, J.A., Jimenez-Perez, S.F., & Morales, J. (2006) Food Chem. 98 , 580 – 585 (5) Narahashi, Y., & Yanagita, M. (1967) J. Biochem. 62 , 633 – 641 (6) Yamaskov, I.A., Tichonova, T.V., & Davankov, V.A. (1986) Enzyme Microb. Tech. 8 , 241 – 244

Conclusions

Performance metrics from the validation work indicate that the method conforms to the range, LOQ, precision, and recovery requirements established in SMPR 2014.013. In addition, specificity appears to be adequate, as evidenced by the failure to detect any apparent Trp in the unfortified sample that was