基于电流驱动离子原位可控释放的固态聚合物膜离子选择性电极检测海水中总氮和硝酸盐氮

This project will focus on all-solid-state polymeric membrane ion-selective electrodes for detection of total nitrogen and nitrate in seawater based on in-situ release of ions controlled by current. The device for the current-controlled release of ions technique is constructed by a cation-selective electrode with inner filling solution coupling with a reference electrode and an indicator electrode. The chloride in seawater can be selectively removed by the release of Ag+ through adding a fixed current on the proposed cation-selective electrode, which could eliminate the matrix interferences from the seawater with the complex components. A magnetic field directed self-assembly method is used to prepare the magnetic graphene-based solid contact, and an all-solid-state polymeric membrane ion-selective electrode is fabricated for sensitive and stable detection of nitrate. By integrating the flow injection system with the current-controlled release of ions technique and potentiometric detection by using the all-solid-state polymeric membrane ion-selective electrode, a new kind of an on-line monitoring system for detection of total nitrogen and nitrate in seawater will be designed. It is anticipated that this project will provide an innovative method for the selective desalination and sensitive and selective monitoring total nitrogen and nitrate in seawater, which could make a contribution to the monitoring fields of marine environment.

本项目将系统研究基于电流驱动离子原位可控释放的固态聚合物膜离子选择性电极检测海水中总氮和硝酸盐氮，深入探讨电流驱动离子原位可控释放技术用于海水选择性脱盐的机理；通过制备内充液式阳离子选择性敏感膜电极，将其与参比电极和指示电极结合，搭建电流驱动离子原位可控释放装置，通过对敏感膜电极施加一定的电流调控内充液离子通量使Ag+原位释放，继而使得海水样品中氯以氯化银形态选择性去除，实现海水基体效应的消除；基于磁场诱导自组装技术制备磁性石墨烯固体接触传导层，并利用其构建固态聚合物膜离子选择性电极，实现硝酸根离子的高灵敏和高稳定性测定；进一步集成流动注射技术、电流驱动离子原位可控释放技术与电位型固态聚合物膜离子选择性电极检测技术，开发一类能够用于海水中总氮和硝酸盐氮测定的在线检测平台。本项目以期在海水选择性脱盐、硝酸盐快速和灵敏检测等方面具有重要的理论和方法创新，为满足国家在海水监测领域的需求做出贡献。

硝酸盐是海水环境监测的必测项目之一，也是海水养殖本底调查的一项重要指标。对硝酸根的检测对于保护海洋生态环境以及对海洋赤潮灾害的预警意义重大。然而，聚合物膜离子选择性电极测定硝酸根时易受因海水高浓度干扰离子介质背景产生的“离子交换效应”和“共萃取效应”的影响，电极的测定灵敏度和稳定性难以满足要求。本项目对固态聚合物膜离子选择性电极检测硝酸根进行了较系统研究，通过发展电流驱动离子原位可控释放技术和恒定电压控制去离子技术，实现了高浓度氯离子的去除；开发了一系列高稳定性固体接触式离子选择性电极，并建立了基于库伦信号和电流信号的固态硝酸根离子选择性电极信号输出检测技术，实现了硝酸根离子的高灵敏和高稳定性测定；将固态硝酸根离子选择性电极、流动注射和电化学工作站耦合，搭建了硝酸根的在线检测装置，实现了硝酸根离子的快速测定。本项目开发的除氯技术，消除了高浓度介质共存的影响；开发的基于离子选择性电极的库伦输出信号和电流信号检测技术，打破了能斯特方程和能斯特理论斜率的限制，提高了离子选择性电极测定灵敏度。本项目共发表SCI论文3篇，中文核心2篇，目前在投1篇SCI论文和1篇中文核心论文；申请专利4项，授权专利3项，参与培养本单位博士生1名和硕士生3名，联合培养硕士生2名；课题成员在国内外会议上做邀请报告/墙报4次；研究团队获得2018年中国海洋工程咨询协会海洋工程科学技术一等奖和2018年中国分析测试协会科学技术一等奖。