“…In our HPLC analysis, a fluorescent peak appeared consistently between the peaks of GTX4 and GTX1. As a matter of fact, some non-PST compounds also gave false fluorescence signals in the post-column reaction system (Gulavita et al, 1988;Onodera et al, 1996;Sato and Shimizu, 1998) and remained under non-oxidizing condition. In our analysis, however, the peak disappeared under the non-oxidizing condition.…”