Ouellet Alexandre, Catana Dragosh, Plouhinec Jean-Baptiste, Lucotte Marc, Gélinas Yves
GEOTOP and Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec, Canada.
Environ Sci Technol. 2008 Apr 1;42(7):2490-5. doi: 10.1021/es702523w.
Portable reverse osmosis (RO) systems are increasingly being used for isolating dissolved organic matter (DOM) from freshwater aquatic systems because of their high volume processing capacity and high absolute DOM recoveries. However, obtaining complete recoveries implies the rinsing of the reverse osmosis system with a solution of dilute NaOH and combining the rinse solution and the DOM concentrate. Because of the potential chemical alterations that can affect the integrity of the organic pool leached from the RO system at high pHs, this approach is not compatible with studies based on the molecular-level analysis of DOM. The potential for elemental, isotopic, and chemical fractionation was thus evaluated on a series of freshwater DOM samples concentrated in the field with a portable RO system when the concentrate and the rinse solution are not combined. DOC recoveries in the concentrate varied between 81.6 and 88.8%, and total balance calculations showed total recoveries of dissolved and particulate organic carbon ranging between 96.4 and 106.9%. Despite similar delta13C signatures, differences in N content and FTIR-based chemical composition between the concentrate and the rinse DOM solutions suggest some degree of chemical fractionation.
便携式反渗透（RO）系统因其高处理量和高绝对溶解有机物（DOM）回收率，越来越多地用于从淡水水生系统中分离DOM。然而，要实现完全回收，意味着要用稀NaOH溶液冲洗反渗透系统，并将冲洗液与DOM浓缩液合并。由于在高pH值下可能发生化学变化，从而影响从RO系统中浸出的有机库的完整性，这种方法与基于DOM分子水平分析的研究不兼容。因此，当不合并浓缩液和冲洗液时，对一系列用便携式RO系统在野外浓缩的淡水DOM样品进行了元素、同位素和化学分馏可能性评估。浓缩液中的DOC回收率在81.6%至88.8%之间，总平衡计算表明，溶解有机碳和颗粒有机碳的总回收率在96.4%至106.9%之间。尽管δ13C特征相似，但浓缩液和冲洗DOM溶液之间的氮含量和基于傅里叶变换红外光谱的化学成分差异表明存在一定程度的化学分馏。
