Marang Laura, Reiller Pascal, Pepe Monique, Benedetti Marc F
CEA Saclay, Nuclear Energy Division, DPC/SECR, Laboratoire de Spéciation des Radionucléides et des Molécules, BP 11, 91191 Gif sur Yvette, France.
Environ Sci Technol. 2006 Sep 1;40(17):5496-501. doi: 10.1021/es060608t.
Metal ion toxicity is not simply related to the total concentration but to the free or labile metal ion concentration. One of the techniques that can measure the free metal ion concentration is the Donnan Membrane Technique (DMT). However, this method has limitations in terms of a relatively high detection limit (in relation to typical environmental concentrations) and a long equilibration time. We have therefore developed the Flux Donnan Membrane (FDM) Technique, which is a dynamic modification of the standard DMT with improved detection limits and a more rapid response. We show that experimental calibrations of metal ion transport in the FDM can be used to measure [M]free under conditions of either solution-controlled or membrane-controlled diffusive transport. The FDM was used to measure cobalt binding isotherms by a humic substance over a large range of free Co concentrations and pH.
金属离子毒性并非仅仅与总浓度相关，而是与游离或不稳定的金属离子浓度有关。能够测量游离金属离子浓度的技术之一是唐南膜技术（DMT）。然而，该方法存在局限性，其检测限相对较高（相对于典型的环境浓度）且平衡时间较长。因此，我们开发了通量唐南膜（FDM）技术，它是对标准DMT的动态改进，具有更低的检测限和更快的响应速度。我们表明，FDM中金属离子传输的实验校准可用于在溶液控制或膜控制的扩散传输条件下测量游离金属离子浓度[M]free。FDM被用于测量腐殖质在大范围游离钴浓度和pH值下的钴结合等温线。
