Evaluation and Adaptation of an Ion Sensitive Field Effect Transistor for Seawater pH Applications

PH值对当代化学海洋学问题，如海洋酸化和生物地球化学循环具有基本重要性，但在空间和时间上仍然长期采样不足。这一问题只能通过开发能够稳定、长期在现场自主运行的传感器来克服。即将到来的海洋观测站时代迫切需要这种传感器用于各种类型的拟议平台(例如系泊、剖面浮标、滑翔机)。S教授建议对用于测量海水pH的离子敏感场效应晶体管的性能进行评价。MBARI的初步测试表明，商业ISFET现在可能能够以最小的传感器漂移在表层海洋中长期运行。MBARI将对商业上可用的ISFET进行并排评估。还将在海洋系泊设备上部署现成的ISFET，以测试生物污损的影响，并确定必要的防生物污损措施。与此同时，MBARI将与现有的芯片技术合作，构建专门用于海水pH测量的ISFET传感器。在设计定制的ISFET时，将特别注意压力容限和参考电极的类型。更广泛的影响：PH值是我们在海洋学研究中最关键的化学参数之一。目前，还没有任何其他进展像Pi的工作那样成功地获得了海水中长期的pH测量。这一发展的好处几乎不限于整个海洋科学界。这一改进的ISFET pH传感器技术对于我们向其他化学传感器发展以获得长期监测能力具有一定的参考价值。此外，通过与传感器相关的开发所获得的经验和知识也将使工程界在处理水体系中的长期化学监测方面受益广泛。现在很难说出比海洋中的碳循环更重要的东西了，这个传感器将极大地帮助我们理解它的时空变异性。一种成功的传感器将在海洋观测系统、各种自主车辆以及舰载野外项目中得到广泛应用。他们的观察计划将让代表不足的群体参与数据分析。

pH is of fundamental importance to contemporary issues in chemical oceanography such as ocean acidification and biogeochemical cycling, yet continues to be chronically undersampled in both space and time. This problem can only be overcome through the development of sensors capable of stable, long-term autonomous operation in situ. The approaching age of ocean observatories desperately needs such sensors for the various types of proposed platforms (e.g. moorings, profiling floats, gliders). The PI?s propose to evaluate the performance of the ion sensitive field effect transistor (ISFET) for measuring seawater pH. Initial tests at MBARI indicate that commercial ISFETs may now be capable of long-term operation in the surface ocean with minimal sensor drift. A side-by-side assessment of commercially available ISFETs will be carried out at MBARI. Off-the-shelf ISFETs will also be deployed on ocean moorings to test the effects of biofouling and to determine the necessary anti-biofouling measures. Concurrent to this, MBARI will work with existing chip technologies to build an ISFET sensor specifically intended for seawater pH measurements. In designing the customized ISFET, special attention will be given to pressure tolerance and type of reference electrode. Broader Impacts: pH value is among the most critical chemical parameters to our study in oceanography. At present time, there is no any other progress as successful as PI's work in obtaining long term pH measurement in seawater. Benefit of this development is almost no limitation to entire ocean science community. The improved ISFET pH sensor technology from this effort will certainly be valuable to our development towards other chemical sensors for gaining long term monitoring ability. In addition, the experience and knowledge gained through this sensor related development will also benefit wide ranges of the engineering community in dealing with long term monitoring of chemistry in aqueous system. Its hard to name anything more important than the carbon cycle in the ocean right now, and this sensor would be a great help in understanding its spatial and temporal variability. A successful sensor would have wide application in ocean observing system and in all sorts of autonomous vehicles as well as ship-based field programs. Their WATCH program will involve under-represented groups in the data analysis.