KWR, Watercycle Research Institute , P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands.
Environ Sci Technol. 2014 Nov 4;48(21):12791-9. doi: 10.1021/es502765e. Epub 2014 Oct 17.
In the past decade during automated surface water monitoring in the river Meuse at border station Eijsden in The Netherlands, a set of unknown compounds were repeatedly detected by online liquid chromatography-diode-array detection in a relatively high signal intensity. Because of the unknown nature of the compounds, the consequently unknown fate of this mixture in water treatment processes, the location being close to the water inlet of a drinking water supply company and their possible adverse public health effects, it was deemed necessary to elucidate the identity of the compounds. No data are available for the occurrence of these unknowns at downstream locations. After concentration and fractionation of a sample by preparative Liquid Chromatography, identification experiments were performed using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HR-MS) combined with High Resolution Nuclear Magnetic Resonance Spectroscopy (HR-NMR). Accurate mass determination of the unknown parent compound and its fragments obtained in MS/MS provided relevant information on the elemental composition of the unknown compounds. With the use of NMR techniques and the information about the elemental composition, the identity of the compounds in the different sample fractions was determined. Beside some regularly detected compounds in surface water, like caffeine and bisphenol-S, five dihydroxydiphenylmethane isomers were identified. The major unknown compound was identified as 4,4'-dihydroxy-3,5,3',5'-tetra(hydroxymethyl)diphenylmethane. This compound was confirmed by analysis of the pure reference compound. This is one of the first studies that employs the combination of high resolution MS with NMR for identification of truly unknown compounds in surface waters at the μg/L level. Five of the seven identified compounds are unexpected and not contained in the CAS database, while they can be presumed to be products generated during the production of resins.
在过去的十年中，荷兰边境站 Eijsden 的默兹河进行了自动化地表水监测，在相对较高的信号强度下，在线液相色谱-二极管阵列检测反复检测到一组未知化合物。由于这些化合物的性质未知，因此它们在水处理过程中的未知命运，该位置靠近一家饮用水供应公司的进水口，以及它们可能对公共健康造成的不利影响，因此有必要阐明这些化合物的身份。在下游位置没有这些未知物的发生数据。对样品进行制备液相色谱浓缩和分级后，使用液相色谱-高分辨率质谱（LC-HR-MS）结合高分辨率核磁共振波谱（HR-NMR）进行了鉴定实验。在 MS/MS 中获得的未知母体化合物及其碎片的精确质量测定为未知化合物的元素组成提供了相关信息。使用 NMR 技术和有关元素组成的信息，确定了不同样品馏分中化合物的身份。除了地表水中常见的一些化合物，如咖啡因和双酚 S 外，还鉴定出了五种二羟二苯甲烷异构体。主要的未知化合物被鉴定为 4,4'-二羟基-3,5,3',5'-四（羟甲基）二苯甲烷。通过对纯参考化合物的分析证实了这一点。这是首次使用高分辨率 MS 与 NMR 结合鉴定地表水μg/L 水平下真正未知化合物的研究之一。鉴定出的七种化合物中有五种是意想不到的，并且不在 CAS 数据库中，但可以假定它们是树脂生产过程中产生的产物。
