Central Institute for Engineering, Electronics and Analytics, Analytics (ZEA-3), Jülich, Germany.
Institute of Bio- and Geosciences, Agrosphere Institute (IBG-3), Forschungszentrum Jülich GmbH , Wilhelm Johnen Straße, 52425 Jülich, Germany.
Environ Sci Technol. 2017 Nov 21;51(22):13256-13264. doi: 10.1021/acs.est.7b03322. Epub 2017 Nov 7.
Liquid-state, one-dimension P nuclear magnetic resonance spectroscopy (NMR) has greatly advanced our understanding of the composition of organic phosphorus in the environment. However, the correct assignment of signals is complicated by overlapping and shifting signals in different types of soils. We applied therefore for the first time diffusion-ordered spectroscopy (DOSY) to soil extracts, allowing us to separate phosphorus components in the second domain based on their translational diffusion coefficients. After successful application to a mixture of 14 model compounds, diffusion rates correlated closely with the molecular weight of the individual compound in aqueous solution (R = 0.97). The method was then applied to NaOH/EDTA extracts of a grassland soil, of which paramagnetic contaminations were removed with sodium sulfide following high-velocity centrifugation (21 500g, 45 min) at 4 °C. Diffusion rates in soil extracts were again closely related to molecular weight (R = 0.98), varying from 163.9 to 923.8 Da. However, our DOSY application failed for a forest soil with low organic phosphorus content. Overall, DOSY did help to clearly identify specific NMR signals like myo- and scyllo-inositol hexakisphosphate. It thus provides a more confident signal assignment than 1D P NMR, although currently the ubiquitous use of this novel methodology is still limited to soils with high organic phosphorus content.
液态、一维磷核磁共振波谱（NMR）极大地促进了我们对环境中有机磷组成的理解。然而，由于不同类型土壤中信号的重叠和移动，正确分配信号变得复杂。因此，我们首次将扩散排序光谱（DOSY）应用于土壤提取物，使我们能够根据它们的平动扩散系数在第二域中分离磷成分。在成功应用于 14 种模型化合物的混合物后，扩散速率与在水溶液中单个化合物的分子量密切相关（R = 0.97）。然后，该方法应用于草地土壤的 NaOH/EDTA 提取物，在用高速度离心（4°C 时 21,500g，45 分钟）去除痕量顺磁污染物后，用亚硫酸钠处理。土壤提取物中的扩散速率再次与分子量密切相关（R = 0.98），范围从 163.9 到 923.8 Da。然而，我们的 DOSY 应用在有机磷含量低的森林土壤中失败了。总体而言，DOSY 确实有助于清楚地识别特定的 NMR 信号，如肌醇六磷酸和鲨肌醇六磷酸。因此，它提供了比 1D P NMR 更有信心的信号分配，尽管目前这种新方法的普遍应用仍然限于有机磷含量高的土壤。
