Potentiometric Autotitration System for Characterizing Reactivity of Environmental Samples

电位滴定在量化环境表面（如微生物、矿物质和有机化合物）的表面反应性方面至关重要，最终目的是能够预测这些表面从水中吸附一系列痕量和重金属的能力。在这个NSERC RTI应用中，我们要求在阿尔伯塔大学（UofA）的一个新的联合Konhauser-Alessi地球生物学实验室中安装一个最先进的自动滴定系统。目前，我们的两个研究小组依赖于一个老化（13岁）滴定仪。该工具在为许多以前和正在进行的研究项目生成数据方面发挥了关键作用，包括：（i）量化海洋浮游生物对微量金属的积累，并确定它们在前寒武纪海洋养分循环和带状铁形成沉积中可能发挥的作用，（ii）评估粘土和含铁矿物结合溶解/颗粒有机碳（DOC/POC）和海水中痕量金属的能力，（iv）评估活性炭、生物炭和石油焦从采矿和垃圾填埋场隔离有毒金属污染物的能力，和（v）与加拿大阿海珐资源公司合作，对退役的克拉夫湖铀矿的尾矿沉积物和池塘沃茨进行表征，萨斯喀彻温省的目的是开发一个具有成本效益和有效的生物修复过程。尽管电位滴定法对环境和应用工业研究都有很好的前景，但我们现有的仪器存在一些局限性，即：（1）它负担过重，学生经常等待数周来进行常规分析，（2）通过仪器添加到溶液中的酸/碱的最小体积对于滴定小体积悬浮液（例如纳米矿物的悬浮液）来说太大，（3）它不能在不对整个仪器进行耗时且引起误差的重新配置的情况下进行正向（碱）和反向（酸）滴定，以及（4）它不能进行电导滴定（或其它滴定，例如氧化还原或卡尔费休滴定）。此外，随着我们的联合实验室的不断发展，我们目前有12个HQP使用这种设备，如果没有现代化的滴定系统，继续这一有前途的研究是不切实际的。除了我们自己的需求，我们还将继续为UofA的其他研究小组提供培训和访问，这些研究小组以前使用过现有的滴定仪，包括Gingras博士（EAS），Owttrim博士（BioSci），Gibbs-Davis博士（化学），Perez和Liu博士（土木工程）。因此，购买新的最先进的滴定系统不仅为我们的实验室团队，而且为UofA提供了巨大的潜力，以提高效率和生产力，并支持许多HQP和NSERC支持的研究项目。

Potentiometric titrations are critical in quantifying the surface reactivity of environmental surfaces, such as microbes, minerals, and organic compounds, with the ultimate aim of being able to predict the ability of those surfaces to sorb a range of trace and heavy metals from water. In this NSERC RTI application, we request a state-of-the-art autotitration system, to be housed in a new joint Konhauser-Alessi Geobiology laboratory at the University of Alberta (UofA). At present, our two research groups depend on one aging (13-year old) titrator. This instrument has been key in generating data for a number of previous and on-going research projects, including: (i) quantifying the accumulation of trace metals by marine plankton, and determining what role they might have played in Precambrian ocean nutrient cycling and banded iron formation sedimentation, (ii) evaluating the ability of clays and iron-bearing minerals to bind dissolved/particulate organic carbon (DOC/POC) and trace metals from seawater, (iii) determining whether DOC can compete with microbes in trace metal adsorption, (iv) assessing the ability of activated carbon, biochar, and petroleum coke to sequester toxic metal contaminants from mining and landfill sites, and (v) working in partnership with AREVA Resources Canada to characterize tailings sediment and pond waters from the decommissioned Cluff Lake uranium mine in Saskatchewan with the aim of developing a cost effective and efficient bioremediation process. Despite the promise potentiometric titrations hold for both environmental and applied industry research, several limitations exist with our existing instrument, namely: (1) it is overtaxed and students often wait weeks to perform routine analyses, (2) the minimum volumes of acid/base added to solutions by the instrument are too large for titrating small-volume suspensions, such as those of nanominerals, (3) it cannot perform forward (base) and reverse (acid) titrations without a time-consuming and error inducing reconfiguration of the entire instrument, and (4) it cannot perform conductometric titrations (or others, such as redox or Karl Fisher titrations). Moreover, with the continued growth of our joint laboratories, we currently have 12 HQP that use this equipment, making it impractical to continue this promising line of research without a modern titration system. In addition to our own needs, we will also continue to provide training and access to other research groups at the UofA who have previously used the existing titrator, including Drs. Gingras (EAS), Owttrim (BioSci), Gibbs-Davis (Chemistry), Perez and Liu (Civil Engineering). Accordingly, the purchase of a new state-of-the-art titration system provides not only our lab group, but also the UofA, with tremendous potential to increase efficiency, productivity, and support a number of HQP and NSERC supported research programs.