Nwosu Ugwumsinachi G, Cook Robert L
Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana.
Environ Eng Sci. 2015 Jan 1;32(1):14-22. doi: 10.1089/ees.2014.0261.
Dissolved organic matter (DOM) is found in most natural waters at concentrations low enough to make DOM isolation methodologies critical to full analytical characterization and preservation. During the last few decades, two major protocols have been developed for the extraction of DOM isolates from natural waters. These methods utilize XAD resins and reverse osmosis (RO). In this work, the hydrophobic acid (May 2012 HPOA) and transphilic acid (May 2012 TPIA) isolates from XAD-8 and XAD-4 resins, respectively, were compared with the RO (May 2012 RO) natural organic matter isolate of the Suwannee River water using C nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies. C NMR analysis showed that the May 2012 RO isolate could be viewed as a hybrid of the more hydrophobic May 2012 HPOA isolate and more hydrophilic May 2012 TPIA isolate. The May 2012 HPOA isolate is shown to be higher in alkyl and aromatic moieties, while the May 2012 TPIA isolate is higher in O-alkyl moieties. EPR analysis revealed that the May 2012 TPIA and, in particular, May 2012 HPOA isolates had higher radical concentrations than the May 2012 RO isolate. It is postulated that some of the radical concentrations came from the use of base during the isolation procedures, especially in the XAD method.
溶解有机物（DOM）存在于大多数天然水体中，其浓度低到足以使DOM分离方法对于全面的分析表征和保存至关重要。在过去几十年中，已经开发出两种从天然水体中提取DOM分离物的主要方法。这些方法利用XAD树脂和反渗透（RO）。在这项工作中，分别从XAD - 8和XAD - 4树脂中获得的疏水酸（2012年5月HPOA）和亲水酸（2012年5月TPIA）分离物，与使用碳核磁共振（NMR）和电子顺磁共振（EPR）光谱法得到的苏万尼河水的RO（2012年5月RO）天然有机物分离物进行了比较。碳核磁共振分析表明，2012年5月的RO分离物可以被视为疏水性更强的2012年5月HPOA分离物和亲水性更强的2012年5月TPIA分离物的混合物。2012年5月的HPOA分离物在烷基和芳基部分含量较高，而2012年5月的TPIA分离物在O - 烷基部分含量较高。电子顺磁共振分析表明，2012年5月的TPIA，特别是2012年5月的HPOA分离物的自由基浓度高于2012年5月的RO分离物。据推测，一些自由基浓度来自分离过程中碱的使用，特别是在XAD方法中。
