The present invention provides a method of measuring the relative ratios of 13C to 12C in an organic compound, e.g. a steroid or a conjugated steroid such as the sulphate conjugate of testosterone, using compound-specific carbon isotope analysis. The method comprises:
subjecting a sample of the compound to hydropyrolysis in the presence of a transition metal catalyst, preferably platinum but also including palladium, rhodium and iridium, under a hydrogen atmosphere at a temperature below 350°C,
subjecting the hydrocarbon product released via hydropyrolysis to gas chromatography to provide a purified sample of the hydropyrolysed product,
combusting the hydropyrolysed product to form carbon dioxide and submitting the resulting carbon dioxide to mass spectrometry to obtain the relative ratios of 13C to 12C in the carbon dioxide.
The method deconjugates the compound from both sulfate or glucuronide moieties when the compound is derived from urine samples and avoids the need to derivatise the compound prior to the gas chromatography step.
本发明提供了一种利用化合物特异性碳同位素分析法测量有机化合物(例如类
固醇或共轭类
固醇,如
睾酮的
硫酸盐共轭物)中 13C 与 12C 相对比率的方法。该方法包括
在 350°C 以下的
氢气环境中,在过渡
金属催化剂(最好是
铂,也包括
钯、
铑和
铱)的存在下,使化合物样品进行加氢分解、
将通过加氢
水解释放出的碳氢化合物产物进行气相
色谱分析,以提供加氢
水解产物的纯化样品、
燃烧氢丙解产物生成
二氧化碳,并将生成的
二氧化碳进行质谱分析,以获得
二氧化碳中 13C 与 12C 的相对比率。
当化合物来自尿液样本时,该方法可将化合物与
硫酸根或
葡萄糖醛酸基解离,从而避免了在气相色谱步骤之前对化合物进行衍生化处理的需要。