### Method Validation by Interlaboratory Studies of Improved Hydrophilic Oxygen Radical Absorbance Capacity Methods for the Determination of Antioxidant Capacities of Antioxidant Solutions and Food ExtractsMethod Validation by Interlaboratory Studies of Improved Hydrophilic Oxygen Radical Absorbance Capacity Methods for the Determination of Antioxidant Capacities of Antioxidant Solutions and Food Extracts

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 Author Watanabe, Jun ♦ Oki, Tomoyuki ♦ Takebayashi, Jun ♦ Yamasaki, Koji ♦ TAKANO-ISHIKAWA, Yuko ♦ Hino, Akihiro ♦ Yasui, Akemi Source J-STAGE Content type Text Publisher The Japan Society for Analytical Chemistry Language English
 Abstract Hydrophilic oxygen radical absorbance capacity (H-ORAC) is a method for evaluating antioxidant capacities of solutions of hydrophilic compounds. In this study, we improved the original method for H-ORAC determination, and evaluated the precision of the two improved methods (methods A and B) by interlaboratory studies using 5 antioxidant solutions and 5 food extracts as test samples. An interlaboratory study of method A, in accordance with the harmonized protocol, demonstrated satisfactory performance (intermediate precision relative standard deviations $(RSD_{int})$ ranging from 4.6 to 18.8%; the reproducibility relative standard deviations $(RSD_{R})$ ranging from 7.0 to 21.1%, and the HorRat values ranging from 0.40 to 1.93). However, methodological problems remained, and a further improved method, method B, was thus developed. An interlaboratory study of method B by 5 participating laboratories showed better intermediate precision and reproducibility $(RSD_{int}$ and $RSD_{R}$ ranging from 1.8 to 9.4%, and from 4.4 to 13.8%, respectively), and all HorRat values for the test samples were less than 1.3, suggesting good performance for the H-ORAC measurement. ISSN 09106340 Learning Resource Type Article Publisher Date 2012-02-10 e-ISSN 13482246 Journal Analytical Sciences(analsci) Volume Number 28 Issue Number 2 Page Count 1 Starting Page 159 Ending Page 159