Determination of 4-Hydroxy-3-methoxyphenylethylene Glycol 4-Sulfate in Human Urine Using Liquid Chromatography−Tandem Mass Spectrometry
作者:Peyton Jacob、Margaret Wilson、Lisa Yu、John Mendelson、Reese T. Jones
DOI:10.1021/ac020101a
日期:2002.10.1
A major metabolite of norepinephrine (NE) in brain is 4-hydroxy-3-methoxyphenylethylene glycol (MHPG). In many species, a large fraction of MHPG formed in brain is converted to the sulfate conjugate. Consequently, MHPG sulfate has been proposed as a biomarker for NE metabolism in the central nervous system. As part of the clinical trials of the monoamine oxidase inhibitor selegiline for treating cocaine addiction, we required a method for measuring urine concentrations of MHPG sulfate. Using a deuterium-labeled analogue as an internal standard, we developed a liquid chromatography−electrospray ionization tandem mass spectrometry (LC−MS/MS) method for determination of MHPG sulfate in human urine. Sample preparation involves simply diluting 50 μL of urine with 1 mL of ammonium formate buffer and adding the internal standard. The sample is centrifuged, the supernate is transferred to an autosampler vial, and 10 μL is injected into the LC−MS/MS system. Standard curves from 50 to 10 000 ng/mL are generated. Only one sample of 277 clinical samples analyzed had a concentration outside of this range. Precision (coefficient of variation) ranged from 1.9 to 9.7%, and accuracy ranged from 97 to 103% of expected values for controls prepared by spiking sulfatase-treated urine with MHPG sulfate.
去甲肾上腺素 (NE) 在大脑中的主要代谢物是 4-羟基-3-甲氧基苯基乙二醇 (MHPG)。在许多物种中,大脑中形成的 MHPG 的很大一部分会转化为硫酸盐结合物。因此,MHPG 硫酸盐被提议作为中枢神经系统 NE 代谢的生物标志物。作为单胺氧化酶抑制剂司来吉兰治疗可卡因成瘾的临床试验的一部分,我们需要一种测量尿液中 MHPG 硫酸盐浓度的方法。使用氘标记类似物作为内标,我们开发了一种液相色谱-电喷雾电离串联质谱 (LC-MS/MS) 方法来测定人尿液中的 MHPG 硫酸盐。样品制备只需用 1 mL 甲酸铵缓冲液稀释 50 μL 尿液并添加内标即可。将样品离心,将上清液转移至自动进样器小瓶中,并将 10 μL 注入 LC-MS/MS 系统。生成 50 至 10 000 ng/mL 的标准曲线。在分析的 277 个临床样本中,只有一个样本的浓度超出此范围。对于通过在硫酸酯酶处理的尿液中添加 MHPG 硫酸盐制备的对照,精密度(变异系数)范围为 1.9% 至 9.7%,准确度范围为预期值的 97% 至 103%。