Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Naoko Sakai.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2016
Maki Kobayashi; Naoko Sakai; Kyoko Kamijo; Harunori Otani; Masaki Hayashi; Hiroshi Koike; Itoko Baba; Takeo Sasamoto; Satoru Nemoto; Tetsuya Shindo; Ichiro Takano
An analytical method for the determination of fluopicolide in livestock products and seafood was developed using LC-MS/MS. Sodium chloride was added to livestock products and seafood samples and fluopicolide was extracted twice with acetone after acidification with formic acid. The fat from the crude extract was removed using a macroporous diatomaceous earth column, followed by purification with a combination of mini-columns of GC (graphite carbon) and PSA (ethylenediamine-N-propyl silylation silica gel). The average recovery (n=5) of fluopicolide from 10 types of livestock products and seafood (cattle fat, cattle liver, cattle muscle, chicken, eel, egg, freshwater clam, honey, milk and salmon) spiked at the MRLs or at the uniform limit (0.01 ppm) was 96-100%, with a relative standard deviation of 2.3-6.2%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2015
Takeo Sasamoto; Maki Kobayashi; Naoko Sakai; Kyoko Kamijo; Harunori Ootani; Masaki Hayashi; Itoko Baba; Chikako Hanashiro; Ichiro Takano
We performed a single-laboratory validation study of a simple and simultaneous determination method for pesticide residues in meat using LC-MS/MS. Water was added to the sample and the mixture was homogenized. Next, pesticides were extracted with acetonitrile containing 1 vol% formic acid using a homogenizer, and salted out with magnesium sulfate, trisodium citrate and sodium chloride. After centrifugation, the acetonitrile layer was made up to standard volume and analyzed by LC-MS/MS. This method was assessed by performing recovery tests in retail bovine, swine and chicken muscle samples spiked with the 132 pesticides at the levels of 0.01 and 0.04 μg/g. Among them, 125 pesticides satisfied the Japanese method validation guideline criteria in bovine, 120 in swine and 127 in chicken.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2007
Maki Kobayashi; Ichiro Takano; Yasuhiro Tamura; Sanae Tomizawa; Yukinari Tateishi; Naoko Sakai; Kyoko Kamijo; Akihiro Ibe
Pesictide residues in 343 samples of domestic rice and 32 samples of imported rice purchased on the Tokyo market from April 1995 to March 2005 were investigated. Residues of eleven kinds of pesticides (including organophosphorus, organochlorine, carbamate, pyrethroid and organonitrogen pesticides and bromide) were detected at levels between trace and 1 ppm in 47 domestic rice samples. DDVP and bromide residues were detected at levels between 0.01 ppm and 5 ppm in 18 imported rice samples. For rice samples that were found to containing pesticides, the amounts of pesticide intake were calculated according to the daily intake of rice, and they were compared with the ADI values. Since residual pesticide levels were 17/10,000-2/5 of ADI, all the rice samples were considered to be safe for human consumption.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2017
Maki Kobayashi; Naoko Sakai; Kyoko Kamijo; Hiroshi Koike; Satoru Nemoto; Tetsuya Shindo
An analytical method based on LC-MS/MS was developed for the determination of formetanate hydrochloride in agricultural products. Formetanate hydrochloride was confirmed to be stable in acetonitrile. It was therefore extracted from samples with acetonitrile, and the crude extracts were purified using a combination of ethylenediamine-N-propyl silylation silica gel and graphite carbon mini columns. Formetanate hydrochloride in the resulting sample solutions was quantified by LC-MS/MS utilizing an external solvent calibration curve. The average recovery (n=5) of formetanate hydrochloride spiked in 10 types of agricultural products (brown rice, soybean, spinach, cabbage, potato, apple, orange, lime, nectarine and green tea) at the maximum residue limits (MRLs) or at a uniform limit of 0.01u2005mg/kg was 92.3-103%, with a relative standard deviation of 1.3-5.4%. The limit of quantitation of the developed method was calculated to be 0.01u2005mg/kg.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2007
Maki Kobayashi; Ichiro Takano; Yasuhiro Tamura; Sanae Tomizawa; Yukinari Tateishi; Naoko Sakai; Kyoko Kamijo; Akihiro Ibe; Toshihiro Nagayama
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2004
Sanae Tomizawa; Ichiro Takano; Maki Kobayashi; Yasuhiro Tamura; Yukinari Tateishi; Naoko Sakai; Kyoko Kitayama; Toshihiro Nagayama; Kunihiro Kamata; Kazuo Saito
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2008
Yasuhiro Tamura; Ichiro Takano; Maki Kobayashi; Sanae Tomizawa; Yukinari Tateishi; Naoko Sakai; Kyoko Kamijo; Akihiro Ibe; Toshihiro Nagayama
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2004
Yukinari Tateishi; Ichiro Takano; Maki Kobayashi; Yasuhiro Tamura; Sanae Tomizawa; Naoko Sakai; Kyoko Kamijo; Toshihiro Nagayama; Kunihiro Kamata
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2010
Yukinari Tateishi; Tsuneo Hashimoto; Keiko Ushiyama; Naoko Sakai; Itoko Baba; Toshihiro Nagayama
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2009
Kyoko Kamijo; Maki Kobayashi; Kenji Otsuka; Yasuhiro Tamura; Sanae Tomizawa; Naoko Sakai; Yuriko Kageyama; Ichiro Takano; Toshihiro Nagayama