Warrack B M, DiDonato G C
Department of Analytical Research and Development, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543.
Biol Mass Spectrom. 1993 Feb;22(2):101-11. doi: 10.1002/bms.1200220202.
The ion spray mass spectra of selected bile acid standards are presented. Full-scan positive ion spectra obtained in solutions of acetonitrile-water-trifluoroacetic acid and methanol-water-trifluoroacetic acid show the presence of intense [M + S + H]+ and [M + 2S + H]+ ions (where S is either methanol or acetonitrile, depending on the solvent system) in addition to [M + H]+ ions. The relative abundance of the protonated and solvent adduct ions are reproducible and unique for several of the bile acids, and provide a means of identifying isomeric bile salts. Adduct ions are most abundant for free acids and weaker for glycine and taurine conjugates. On-line ion spray liquid chromatography/mass spectrometry (LC/MS) using a 3 cm x 4.6 mm cartridge column containing 3 microns particle size C18 packing was utilized for the separation and identification of components of monkey bile. Eight common bile acid conjugates were separated in less than 8 min utilizing a water-acetonitrile gradient with 0.1% trifluoroacetic acid as the mobile-phase modifier. Full-scan data were acquired from 1 microliter of untreated bile injected on-column. Identification of component bile acids from the equivalent of 1 nl injected on-column was obtained with the use of a 1 mm diameter microbore column. Limits of detection for bile acid conjugates using a microbore column and selected ion monitoring (SIM) range from 40 to 100 fmol.
文中给出了选定胆汁酸标准品的离子喷雾质谱图。在乙腈 - 水 - 三氟乙酸和甲醇 - 水 - 三氟乙酸溶液中获得的全扫描正离子谱图显示，除了[M + H]+离子外，还存在强烈的[M + S + H]+和[M + 2S + H]+离子（其中S为甲醇或乙腈，取决于溶剂系统）。对于几种胆汁酸而言，质子化离子和溶剂加合物离子的相对丰度具有可重复性且独一无二，这为鉴定异构胆汁盐提供了一种方法。加合物离子在游离酸中最为丰富，而在甘氨酸和牛磺酸共轭物中则较弱。使用一根3 cm×4.6 mm的柱管，内装粒径为3微米的C18填料，通过在线离子喷雾液相色谱/质谱联用（LC/MS）对猴胆汁的成分进行分离和鉴定。利用水 - 乙腈梯度，并以0.1%三氟乙酸作为流动相改性剂，在不到8分钟的时间内分离出了8种常见的胆汁酸共轭物。从1微升未经处理的柱上进样胆汁中采集全扫描数据。使用内径为1 mm的微径柱，可对相当于1 nl柱上进样量的胆汁酸成分进行鉴定。使用微径柱和选择离子监测（SIM）时，胆汁酸共轭物的检测限为40至100飞摩尔。
