@article{oai:nagasaki-u.repo.nii.ac.jp:00007451,
 author = {近藤, 寛 and 石渡, 良志 and 山本, 修一 and 上村, 仁},
 journal = {長崎大学教育学部自然科学研究報告, Science bulletin of the Faculty of Education, Nagasaki University},
 month = {May},
 note = {In the course of a gas chromatographi-mass spectrometric (GC/MS) study of sterols from marine sediments, we previously identified the major sterols: 5a-stanols, △5_, △22_ and △5, 22_ sterols (Kondo et al., 1991). The present paper reports successively the identification of 19 different 4-desmethyl-sterols which are classified into 7 groups, including 5β-stanols △5, 24_, △7_, △5, 24(28)_ and △24(28)_ sterols. The mass spectra data of these sterol trimethylsilyl ether derivatives are presented in Table 2 and Fig.s 8-11. 5β-Stanols have shorter GC retention times (RRT) than the corresponding 5a-stanols. These derivatives give intense peaks of b[M-90]+ and have molecular ions [M]+ of low density. 3β-Epimer has a shorter RRT and a stronger peak at m/z108 than 3a-epimer. △5,24-Sterols present strong ions d , b, r and s at m/z372, 366, 343 and 253 respectively. They also have ions n[M-129] m/z129 which are intense in the case of △5-sterols. △7-Sterols are characterized, as having longer RRT than the corresponding △5-sterols, and by the base peaks at em/z255, and by the intense molecular ions [M]+. Thepresence of a △24(28) double bond in the sterol side chain brings about intense fragment ions p [M-C23～C26(23)-H]+ and q [M-C23～C26(23)-H-ROH], etc. corresponding to the cleavage of the 23-24 double bond due to the Mclafferty-type rearrangement. In the case of △5,24(28)-sterols, the characteristic ions p at m/z386 and q at m/z296 are accompanied by ions n[M-129]+, m/z145, 129 all of which are typical of △5-sterols. △24(28)-Sterols have characteristic ions p at m/z388 and g at m/z215 which are strong in the 5a-saturated sterols., 長崎大学教育学部自然科学研究報告. vol.45, p.27-47; 1991},
 pages = {27--47},
 title = {現世海洋堆積物中のステロ-ル-2 : 4-デスメチルステロールのGC/MSによる解析},
 volume = {45},
 year = {1991}
}