公定法およびその修正法による食品中ビタミンD定量分析の試験室間共同試験

竹林 純; 谷中 かおる; 松本 輝樹; 飯塚 太由; 萩原 拓幸; 布施 浩二; 堀内 匠; 美馬 晴之; 安河内 義和; 吉田 幹彦; 山田 和彦; 石見 佳子

doi:10.20632/vso.85.12_645

Determination of Vitamin D in Foods by the Official Method in Japan and Its Modified Method : Interlaboratory Studies

Jun Takebayashi, Kaoru Yanaka, Teruki Matsumoto, Tayoshi Iizuka, Takuyuki Hagiwara, Koji Fuse, Takumi Horiuchi, Haruyuki Mima, Yoshikazu Yasukouchi, Mikihiko Yoshida, Kazuhiko Yamada, Yoshiko Ishimi

Author information

Jun Takebayashi
Department of Food Function and Labeling, Incorporated Administrative Agency, National Institute of Health and Nutrition
Kaoru Yanaka
Department of Food Function and Labeling, Incorporated Administrative Agency, National Institute of Health and Nutrition
Teruki Matsumoto
Department of Food Function and Labeling, Incorporated Administrative Agency, National Institute of Health and Nutrition
Tayoshi Iizuka
Japan Inspection Association of Food and Food Industry Environment
Takuyuki Hagiwara
Osaka City Institute of Public Health and Environmental Sciences
Koji Fuse
Department of Nutritional Sciences, Japan Food Research Laboratories, Tama Laboratory
Takumi Horiuchi
Japan Frozen Foods Inspection Corporation
Haruyuki Mima
Japan Inspection Association of Food and Food Industry Environment
Yoshikazu Yasukouchi
Japan Frozen Foods Inspection Corporation
Mikihiko Yoshida
Department of Nutritional Sciences, Japan Food Research Laboratories, Tama Laboratory
Kazuhiko Yamada
Laboratory of Biochemistry, Kagawa Nutrition University
Yoshiko Ishimi
Department of Food Function and Labeling, Incorporated Administrative Agency, National Institute of Health and Nutrition

Keywords: precision of determination of vitamin D, official and modified methods, interlaboratory study, high performance liquid chromatography (HPLC)

JOURNAL FREE ACCESS

2011 Volume 85 Issue 12 Pages 645-650

DOI https://doi.org/10.20632/vso.85.12_645

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Abstract

The two-step high performance liquid chromatography (HPLC) method, that is, preparative HPLC (reverse-phase) followed by analytical HPLC (normal-phase), is used as the Japanese official method to determine the content of vitamin D in food. We first performed an interlaboratory study to estimate precision of the official method using the certificated formula milk (NIST, SRM 1849). The relative standard deviations (RSDs) of the official method for intermediate precision and reproducibility were 16.5 and 18.6%, respectively. We considered that non-polar insoluble interferences may disturb re-dissolution of vitamin D in the sample solutions which are applied to the preparative HPLC (reverse-phase). Therefore, we investigated a modified method in which preparative HPLC (normal-phase) was followed by analytical HPLC (reverse-phase), in order to reduce the insoluble substances. An interlaboratory study using 4 commercial formula milk available in Japan showed that the intermediate- and reproducibility-RSD of the modified method were ranged from 6.7 to 12.9% and from 7.4 to 18.9%, respectively. These results suggest good performance of the modified method.

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