Setchell K D, Vestal C H
Department of Pediatrics, Children's Hospital Medical Center, Cincinnati, OH 45229.
J Lipid Res. 1989 Sep;30(9):1459-69.
A rapid, highly specific and sensitive combined high performance liquid chromatography-mass spectrometric (LC-MS) method is described for the analysis of bile acids in biological fluids. Ionization of polar bile acid conjugates is achieved in the thermospray interface that is used to directly couple the LC column to the mass spectrometer, thereby allowing continuous monitoring of the LC effluent. Maximum sensitivity (4-10 pmol) is achieved by recording the negative ions generated in the ionization process and mass spectra obtained for the principal bile acid conjugates are characterized by intense [M-H]-pseudo-molecular ions and fragment ions due to consecutive losses of water corresponding to a number of hydroxyl groups in the molecule. The mass spectrometer thus provides molecular weight and useful structural information for each compound separated by HPLC. Applications of the LC-MS technique to the analysis of bile acids in bile and serum samples after an initial solid-phase extraction step highlight the potential of the thermospray interface for enhancing the specificity and sensitivity of the HPLC technique for bile acid analysis.
本文描述了一种快速、高度特异且灵敏的高效液相色谱 - 质谱联用（LC - MS）方法，用于分析生物流体中的胆汁酸。极性胆汁酸共轭物在热喷雾接口中实现离子化，该接口用于将液相色谱柱直接与质谱仪相连，从而能够连续监测液相色谱流出物。通过记录电离过程中产生的负离子可实现最大灵敏度（4 - 10皮摩尔），主要胆汁酸共轭物的质谱特征为强烈的[M - H] - 准分子离子以及由于分子中多个羟基连续失水而产生的碎片离子。因此，质谱仪可为通过高效液相色谱分离的每种化合物提供分子量和有用的结构信息。在最初的固相萃取步骤之后，将LC - MS技术应用于胆汁和血清样品中胆汁酸的分析，突出了热喷雾接口在增强高效液相色谱技术用于胆汁酸分析的特异性和灵敏度方面的潜力。
