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

地球上的海洋和海洋沃茨在一系列关键金属元素的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（如铁）有关，其健康可能受到包括金属在内的各种人为投入的负面影响。然而，为了让我们了解这些金属的循环和影响，需要在高频率和长时间内测量关键化学物质。一系列可能有潜力提供这些数据的原位技术开始出现，包括芯片上实验室技术，这些技术具有体积小、试剂和功率要求有限的显著优势。然而，即使最近在单元设计和降噪方面取得了进展，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沃茨中重要金属的极低浓度[pM至nM]。在这里，我们建议学生开发一种新的和创新的方法，通过使用芯片螯合树脂预浓缩提高灵敏度。南安普顿国家海洋学中心的海洋微系统中心将南安普顿大学的技能和科学资源与国家海洋学中心的自然环境研究理事会传感器科相结合，组成了一个国际知名的研究小组，致力于海洋传感器技术的前沿[见www.soton.ac.uk/rmst]。这个大型团体的兴趣从微流体和微机械专业知识延伸到生物污垢研究，为拟议领域的研究生培训提供了良好的环境，并将开发NERC资助的领先技术的新应用，以回答关键的环境问题。该小组的几个海洋原位传感器已经处于技术准备水平4-6，并通过PI斯坦森为拟议项目提供额外的化学分析技能。将海洋和地球科学学院目前成功用于台式流动注射分析仪系统的树脂预浓缩程序缩小到武装冲突法的规模是一项具有挑战性的分析和技术工作。该项目的各个阶段将首先涉及学生通过小组讲座和实践经验来掌握武装冲突法技术，然后在武装冲突法设备上实施树脂技术。这项工作将首先使用Mn作为测试金属，因为相对于例如天然沃茨中的Fe，Mn的形态复杂性降低，并且在SOES实验室中存在用于分析Mn的工作皮摩尔台系统。在树脂-LOAC系统的微流体表征之后，将测试所选树脂床的容量以及吸收和洗脱特性。一旦这些阶段完成，新装置将被纳入新的武装冲突法系统，该系统将把树脂系统和现有的比色武装冲突法设计结合起来。实验室测试将包括海洋系统的典型温度和压力，以及分析数字，因此将产生优点，包括使用经认证的参考材料进行准确性测试。现场测试将使用NOCS仪表码头测试场地。一旦原理已被证明为锰不同的树脂将被应用于海水中溶解铁的测定。除了NERC科学的主要应用（全球碳泵、Fe添加地球工程概念的进一步测试和环境质量）之外，这种分析装置还将应用于淡水和潜在的工业系统，其中在LOAC装置上使用元素特异性树脂可以用于在分析之前去除干扰元素，以及预浓缩分析物。

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.