Ostlund R E, Hsu F F, Bosner M S, Stenson W F, Hachey D L
Division of Endocrinology, Diabetes and Metabolism, Washington University, St. Louis, MO 63110, USA.
J Mass Spectrom. 1996 Nov;31(11):1291-6. doi: 10.1002/(SICI)1096-9888(199611)31:11<1291::AID-JMS424>3.0.CO;2-5.
Because of its high sensitivity, gas chromatography negative ion chemical ionization mass spectrometry (GC-NCI-MS) is a potentially valuable analytical tool for the study of cholesterol metabolism. Of several derivatives prepared for potential use in tracer studies pentafluorobenzoyl cholesterol was selected because it formed rapidly at ambient temperature and was stable for long periods, could be detected at a level of 1 fmol, and yielded a mass spectrum in which the molecular ion was the principal component. Hexadeuterated cholesterol tracer ([26,26,26,27,27,27-2H6]cholesterol) could be detected in dilutions up to 2700 in unlabeled cholesterol by selected ion monitoring with a coefficient of variation averaging 3.2%. In seven normal subjects tracer cholesterol was infused intravenously and plasma cholesterol enrichment was determined after 4 h. The measured rapidly miscible cholesterol pool was 391.0 +/- 38.6 mg cholesterol/kg. Negative ion mass spectrometry of pentafluorobenzyol cholesterol will facilitate analysis of both small amounts of natural cholesterol and labeled cholesterol in applications where sensitivity is critical.
由于其高灵敏度，气相色谱负离子化学电离质谱法（GC-NCI-MS）是研究胆固醇代谢的一种潜在有价值的分析工具。在为示踪研究准备的几种衍生物中，选择了五氟苯甲酰胆固醇，因为它在室温下能快速形成且长期稳定，能在1飞摩尔的水平上被检测到，并且产生的质谱中分子离子是主要成分。通过选择离子监测，在未标记的胆固醇中，六氘代胆固醇示踪剂（[26,26,26,27,27,27-2H6]胆固醇）在高达2700倍稀释度时仍能被检测到，变异系数平均为3.2%。在7名正常受试者中，静脉注射示踪胆固醇，并在4小时后测定血浆胆固醇富集情况。测得的快速混合胆固醇池为391.0±38.6毫克胆固醇/千克。在灵敏度至关重要的应用中，五氟苯甲酰胆固醇的负离子质谱将有助于分析少量天然胆固醇和标记胆固醇。
