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Featured researches published by Toshihiro Nagayama.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2013
Tomoya Yoshinari; Toshitsugu Tanaka; Eiichi Ishikuro; Masakazu Horie; Toshihiro Nagayama; Masahiro Nakajima; Shigehiro Naito; Takahiro Ohnishi; Yoshiko Sugita-Konishi
To validate an LC-MS/MS method for simultaneous determination of deoxynivalenol (DON) and its acetylated derivatives, 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON), in wheat using a multifunctional column, an inter-laboratory study was performed in 9 laboratories using one blank wheat sample, three spiked wheat samples (10, 50, 150 µg/kg) and one naturally contaminated wheat sample. The recoveries ranged from 98.8 to 102.6% for DON, 89.3 to 98.7% for 3ADON, and from 84.9 to 90.0% for 15ADON. The relative standard deviations for repeatability (RSDR) and reproducibility (RSDR) of DON were in the ranges of 7.2-11.3% and 9.5-22.6%, respectively. For 3ADON, the RSDR ranged from 5.3 to 9.5% and the RSDR ranged from 16.1 to 18.0%, while for 15ADON, the RSDR ranged from 6.2 to 11.2% and the RSDR ranged from 17.0 to 27.2%. The HorRat values for the three analytes ranged from 0.4 to 1.2. These results validate this method for the simultaneous determination of DON and its acetylated derivatives, 3ADON and 15ADON.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2011
Takayuki Nakajima; Hiroshi Hayashi; Takeo Sasamoto; Maki Kanda; Tomoko Kusano; Youko Matsushima; Setsuko Kanai; Kazue Takeba; Toshihiro Nagayama
We studied the simultaneous determination of nequinate and buquinolate, which are used as feed additives to prevent coccidiosis, by means of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The sample was extracted with acetonitrile, then loaded onto an HLB mini-column with 20% methanol. After clean-up with 20% methanol, the analytes were eluted with acetonitrile-methanol (1 : 1). The coccidiostats in the purified samples were determined using ESI-MRM mode LC-MS/MS with a sample matrix calibration curve. Mean recoveries of nequinate and buquinolate from 8 kinds of livestocks samples (chicken muscle, chicken liver, chicken heart, swine muscle, swine heart, cattle muscle, sheep muscle, egg) were in the range of 89.5% to 108.6%, and the relative standard deviation values were <20% (n=10) at the levels of 0.01 μg/g and 0.05 μg/g, respectively. The limits of quantification of these compounds were 0.001 μg/g in each sample.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2008
Maki Kanda; Tomoko Kusano; Taka Osanai; Keiko Ushiyama; Kazue Takeba; Miho Sakamoto; Hiroshi Hayashi; Kyoko Igusa; Akihiro Ibe; Toshihiro Nagayama
A rapid and precise determination residues of 4 tetracyclines (TCs) (oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC) and doxycycline (DOXY)) in meat was developed by employing three analyses; a microbiological screening, HPLC and LC/MS/MS. TCs were extracted with pH 4.0 McIlvaine buffer containing 0.01 mol/L EDTA from a meat sample, and then purified using a mixed mode, reversed-phase and cation-exchange cartridge. The mean recoveries (n=5) of 0.2 microg/g OTC, TC and CTC, 0.05 microg/g DOXY spiked in meat samples were 76.6-99.0% (C.V. 1.6-5.4%). In 13 meat samples in which the microbiological screening indicated the presence of TCs, CTC (9 samples) and DOXY (4 samples) were identified with HPLC and LC/MS/MS.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2000
Satoru Nemoto; Kumiko Sasaki; Syuichi Eto; Isao Saito; Hiroshi Sakai; Tetsuo Takahashi; Yasuhide Tonogai; Toshihiro Nagayama; Shinjiro Hori; Yoshiaki Maekawa; Masatake Toyoda
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 1979
Hisashi Kamimura; Motohiro Nishijima; Kazuo Saito; Kazuo Yasuda; Akihiro Ibe; Toshihiro Nagayama; Hirofumi Ushiyama; Yasuta Naoi
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 1998
Tsuneo Hashimoto; Toshihiro Nagayama; Maki Kobayashi; Nahoko Haneishi; Masako Ito; Yasuhiro Tamura; Toshio Tomomatsu
Journal of Pesticide Science | 2005
Toshihiro Nagayama
Journal of Pesticide Science | 1989
Toshihiro Nagayama; Toshio Maki; Kimiko Kan; Mami Iida; Yukihiro Tamura; Taichiro Nishima
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 1994
Toshihiro Nagayama; Maki Kobayashi; Hiroko Shioda; Masayo Morino; Masako Ito; Yukihiro Tamura
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