Departments of Chemistry and of Chemical and Biological Engineering, Iowa State University, Institute for Combinatorial Discovery, Ames, IA 50011, United States.
Talanta. 2010 Mar 15;80(5):1606-10. doi: 10.1016/j.talanta.2009.09.056. Epub 2009 Oct 3.
The increase in bacterial resistance to antibiotics has led to resurgence in the use of silver as a biocidal agent in applications ranging from washing machine additives to the drinking water treatment system on the International Space Station (ISS). However, growing concerns about the possible toxicity of colloidal silver to bacteria, aquatic organisms and humans have led to recently issued regulations by the US EPA and FDA regarding the usage of silver. As part of an ongoing project, we have developed a rapid, simple method for determining total silver, both ionic (silver(I)) and colloidal, in 0.1-1mg/L aqueous samples, which spans the ISS potable water target of 0.3-0.5mg/L (total silver) and meets the US EPA limit of 0.1mg/L in drinking water. The method is based on colorimetric solid-phase extraction (C-SPE) and involves the extraction of silver(I) from water samples by passage through a solid-phase membrane impregnated with the colorimetric reagent DMABR (5-[4-(dimethylamino)benzylidene]rhodanine). Silver(I) exhaustively reacts with impregnated DMABR to form a colored compound, which is quantified using a handheld diffuse reflectance spectrophotometer. Total silver is determined by first passing the sample through a cartridge containing Oxone, which exhaustively oxidizes colloidal silver to dissolved silver(I). The method, which takes less than 2 min to complete and requires only approximately 1 mL of sample, has been validated through a series of tests, including a comparison with the ICP-MS analysis of a water sample from ISS that contained both silver(I) and colloidal silver. Potential earth-bound applications are also briefly discussed.
细菌对抗生素的耐药性增加导致银作为一种杀菌剂在从洗衣机添加剂到国际空间站（ISS）饮用水处理系统等应用中的使用重新兴起。然而，人们对胶体银对细菌、水生生物和人类可能的毒性的担忧日益增加，导致美国环保署（EPA）和美国食品和药物管理局（FDA）最近发布了关于银使用的规定。作为正在进行的项目的一部分，我们开发了一种快速、简单的方法，用于测定 0.1-1mg/L 水样中的总银，包括离子（银（I））和胶体，涵盖了 ISS 饮用水目标 0.3-0.5mg/L（总银），并符合美国环保署在饮用水中 0.1mg/L 的限值。该方法基于比色固相萃取（C-SPE），涉及通过穿过固相膜来从水样中萃取银（I），该固相膜浸渍有比色试剂 DMABR（5-[4-（二甲氨基）苄叉基]罗丹宁）。银（I）与浸渍的 DMABR 彻底反应形成有色化合物，使用手持漫反射分光光度计定量。总银的测定方法是首先通过含有 Oxone 的筒，该筒将胶体银彻底氧化成溶解的银（I）。该方法不到 2 分钟即可完成，只需大约 1 毫升样品，已经通过一系列测试进行了验证，包括与来自 ISS 的含有银（I）和胶体银的水样的 ICP-MS 分析进行比较。还简要讨论了潜在的地球应用。
