Improvement of 31P NMR Spectral Resolution by 8-Hydroxyquinoline Precipitation of Paramagnetic Fe and Mn in Environmental Samples
Improvement of 31P NMR Spectral Resolution by 8-Hydroxyquinoline Precipitation of Paramagnetic Fe and Mn in Environmental Samples
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DOI：
10.1021/es903558g
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发表时间：
2010-04-01
影响因子：
11.4
通讯作者：
Zhang, Chaosheng
中科院分区：
文献类型：
--
作者：
Ding, Shiming;Xu, Di;Zhang, Chaosheng
溶液P-31核磁共振（NMR）波谱是目前表征环境样品中磷（P）形态的主要方法。然而，顺磁性 Fe 和 Mn 造成的光谱分辨率差可能会阻碍 P 化合物的识别和定量。在这项研究中，开发了一种新技术，通过 8-羟基喹啉 (8-HOQ) 沉淀从碱性提取物中去除顺磁性铁和锰，从而提高光谱分辨率。批量实验表明，在pH 9.0下沉淀可以有效去除Fe和Mn，对5种不同环境样品的提取物中Fe和Mn的去除效率分别为83-91%和67-78%，而对总P浓度影响不大。模型P溶液的P-31 NMR分析表明，添加8-HOQ。其与金属离子的沉淀不会改变P的形式。用 P-31 NMR 光谱对五种提取物进行进一步分析表明，与目前的后提取技术（例如碳酸氢二硫酸盐 (BD)、EDTA 和 Chelex-100 处理）相比，8-HOQ 沉淀是一种理想的方法，可在很大程度上提高光谱分辨率，同时对 P 形式没有不利影响。
Solution P-31 nuclear magnetic resonance (NMR) spectroscopy is currently the main method for the characterization of phosphorus (P) forms in environment samples. However, identification and quantification of P compounds may be hampered by poor resolution of spectra caused by paramagnetic Fe and Mn. In this study, a novel technique was developed to improve spectral resolution by removing paramagnetic Fe and Mn from alkaline extracts via 8-hydroxyquinoline (8-HOQ) precipitation. Batch experiments showed that both Fe and Mn were effectively removed by the precipitation at pH 9.0, with the removal efficiencies of 83-91% for Fe and 67-78% for Mn from the extracts of five different environmental samples, while little effect was found on concentration of total P. The P-31 NMR analysis of a model P solution showed that addition of 8-HOQ. and its precipitation with metal ions did not alter P forms. Further analyses of the five extracts with P-31 NMR spectroscopy demonstrated that the 8-HOQ precipitation was an ideal method compared with the present postextraction techniques, such as bicarbonate dithionate (BD), EDTA and Chelex-100 treatments, by improving spectral resolution to a large extent with no detrimental effects on P forms.