Department of Analytical Chemistry, Faculty of Pharmaceutical Science, Hoshi University, Ebara 2-4-41, Shinagawa-ku, Tokyo 142-8501, Japan; Laboratory of Analytical Chemistry, School of Pharmaceutical Science, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-0071, Japan; and Research and Development Division of Kikkoman Corporation, Noda 399, Noda-shi, Chiba Prefecture 278-0037, Japan(1999-10-06時点)