Novel advances in lab on a chip instruments for in situ measurement of trace metals in marine waters

我们这个星球的海洋和海水在一系列关键金属元素的生物地球化学循环中发挥着重要作用，这些金属元素与气候变异性和海洋生产力(例如铁)有关，这些元素的健康可能受到包括金属在内的各种人为输入的负面影响。然而，为了了解这些金属的循环和影响，需要在高频和较长的时间段内测量关键化学物种。一系列可能提供这些数据的现场技术开始出现，其中包括芯片实验室(LOAC)技术，这些技术具有体积小、试剂和电力需求有限的显著优势。然而，即使在电池设计和降噪方面取得了最近的进展，这些LOAC系统也没有足够的灵敏度来确定海洋系统中绝大多数水域中极低浓度的重要金属[PM到NM]。在这里，我们建议一个学生开发了一种新的创新方法，通过使用芯片上的螯合树脂预浓缩来提高灵敏度。南安普敦国家海洋学中心的海洋微系统中心[NOCS]将南安普顿大学的技能和科学资源与国家海洋研究中心的自然环境研究理事会传感器部门结合起来，提供了一个致力于海洋传感器技术前沿的国际知名研究小组[见www.soton.ac.uk/rmst]。这个兴趣从微流体学和微机械专业知识到生物污垢研究的庞大小组为拟议领域的研究生提供了一个极好的培训环境，并将开发国家环境研究中心资助的领先技术的新应用，以回答关键的环境问题。该小组的几个海洋现场传感器已经达到技术准备级别4-6，并通过Pi Statham为拟议的项目提供了更多的化学分析技能。将目前在海洋与地球科学学院台式流动注射分析仪系统中成功使用的树脂预浓缩程序缩减到LOAC尺寸是一项具有挑战性的分析和技术工作。该项目的各个阶段最初将包括学生通过讲座和小组实践经验掌握LOAC技术，然后在LOAC设备上实施树脂技术。这项工作将首先使用锰作为测试金属，因为相对于天然水中的铁，形态形成的复杂性较低，而且国有企业实验室存在一个正在运行的皮摩尔试验台系统来分析锰。在对树脂-LOAC系统进行微流体表征后，将测试选定的树脂床的容量、吸收和洗脱特性。一旦这些阶段完成，新的单元将被整合到一个新的LOAC系统中，该系统将结合树脂系统和现有的色度LOAC设计。实验室测试将包括典型的海洋系统的温度和压力，以及分析数据，因此将产生优点，包括使用经认证的标准物质的准确性测试。现场测试将使用NOCS仪表式码头测试场。一旦证明了锰的原理，就可以用不同的树脂测定海水中的溶解铁。除了NERC科学的主要应用(全球碳泵、铁添加地球工程概念的进一步测试和环境质量)外，这类分析设备还将应用于淡水和潜在的工业系统，在这些系统中，LOAC设备上的元素专用树脂可用于在分析前去除干扰元素，以及对分析物进行预浓缩。

The oceans and marine waters of our planet play a major role in the biogeochemical cycles of a range of key metal elements that are linked with climatic variability and ocean productivity (e.g. Fe), and the health of which may be negatively impacted by a variety of anthropogenic inputs including metals. However, for us to understand the cycles and impacts of these metals there is a need for measurements of key chemical species at high frequency and over extended time periods. A range of in situ technologies are beginning to emerge that may have the potential to provide these data, including lab on a chip (LOAC) technologies that have the significant advantages of small size, and limited reagent and power requirements. However, even with recent developments in cell design and noise reduction, these LOAC systems do not have adequate sensitivity for determining the extremely low concentrations [pM to nM] of important metals in the vast majority of the waters in the ocean system. Here we propose a student develops a new and innovative approach to enhancing sensitivity through use of on chip chelating resin pre-concentration. The Centre for Marine Microsystems at the National Oceanography Centre, Southampton [NOCS] combines skills and scientific resources from across the University of Southampton with the Natural Environment Research Council sensor section at NOCS to provide an internationally known research group working at the leading edge of marine sensor technology [see www.soton.ac.uk/rmst]. This large group with interests extending from micro fluidics and micromechanical expertise, to studies on biofouling provides an excellent environment for the training of a research student in the proposed area, and will develop new applications of the NERC funded leading technology being developed to answer crucial environmental questions. Several marine in situ sensors from the group are already at technology readiness levels 4-6, and additional chemical analytical skills are provided through the PI Statham for the proposed project. Scaling down the resin pre-concentration procedures that are currently successfully used in bench-top flow injection analyser systems at the School of Ocean and Earth Science to LOAC dimensions is a challenging analytical and technological exercise. The phases in the project will initially involve the student getting up to speed with LOAC technology through lectures and hands on experience in the group, followed by the implementation of resin technology on a LOAC device. The work will at first use Mn as a test metal because of reduced complexity in speciation relative to e.g. Fe in natural waters, and the presence of a working picomolar bench system for analysing Mn in the SOES laboratory. After microfluidic characterisation of the resin-LOAC system, the selected resin bed will be tested for capacity, plus uptake and elution characteristics. Once these stages are complete, the new unit will be integrated into a new LOAC system that will combine the resin system and an existing colorimetric LOAC design. Laboratory testing will include temperatures and pressures typical of marine systems, and analytical figure so merit will be generated including testing of accuracy with certified reference materials. Field testing will use the NOCS instrumented jetty test site. Once the principals have been demonstrated for Mn a different resin will be applied to the determination of dissolved Fe in seawater. In addition to primary applications to NERC science (global carbon pump, further testing of Fe addition geo-engineering concepts, and environmental quality) such analytical devices will have applications to freshwater and potentially industrial systems where the use of element specific resins on LOAC devices may ber used to remove interfering elements prior to analysis, as well as pre-concentrating the analyte.