Department of Medical Technology, Ehime Prefectural University of Health Sciences, Ehime, Japan.
Department of Clinical Laboratory, School of Medicine, the University of Tokyo, Tokyo, Japan.
Sci Rep. 2018 Jul 27;8(1):11364. doi: 10.1038/s41598-018-29769-w.
The urine of patients with alkaptonuria turns dark brown due to the oxidation of homogentisic acid (HGA) to benzoquinone acetic acid (BQA), and this is accelerated by the addition of alkali. We recently reported that alkaptonuric urine and HGA after the addition of alkali showed characteristic peaks at 406 and 430 nm. In order to improve the sensitivity of our spectrometric method for the detection of HGA, we accelerated the oxidation of HGA to BQA using sodium hypochlorite pentahydrate (NaOCl·5HO), which is a strong oxidant. In the present study, we measured the absorption spectra of alkaptonuric urine and HGA solution after the addition of sodium hydroxide (NaOH) or NaOH with NaOCl·5HO and analyzed the oxidation reaction of HGA after alkalization using a liquid chromatography time-of-flight mass spectrometer (LC/TOF-MS) and nuclear magnetic resonance (NMR) spectrometry. We accelerated the oxidation of HGA to BQA by adding NaOH with NaOCl·5HO, and this absorbance measurement was useful for more sensitively observing the oxidation of HGA than LC/TOF-MS and NMR spectroscopy. This quick and easy screening method may be suitable for the diagnosis of alkaptonuria.
尿黑酸尿症患者的尿液由于对-羟基苯乙酸（HGA）氧化为苯醌乙酸（BQA）而变成深棕色，这一过程会被加入碱所加速。我们最近报道，加入碱后的尿黑酸尿症患者尿液和 HGA 会在 406nm 和 430nm 处出现特征峰。为了提高我们对 HGA 的光谱检测方法的灵敏度，我们使用五水合次氯酸钠（NaOCl·5HO）作为一种强氧化剂来加速 HGA 向 BQA 的氧化。在本研究中，我们测量了加入氢氧化钠（NaOH）或 NaOH 与 NaOCl·5HO 后的尿黑酸尿症患者尿液和 HGA 溶液的吸收光谱，并使用液相色谱飞行时间质谱（LC/TOF-MS）和核磁共振（NMR）光谱分析了碱化后 HGA 的氧化反应。我们通过加入 NaOH 和 NaOCl·5HO 加速了 HGA 向 BQA 的氧化，与 LC/TOF-MS 和 NMR 光谱相比，这种吸光度测量对于更敏感地观察 HGA 的氧化更为有用。这种快速简便的筛选方法可能适用于尿黑酸尿症的诊断。
