| Nowadays, the environmental issues in China have been of more and more concerns with the rapid development of economy. A wide range of human activities, such as industry, agriculture, exploitation of mineral resources, contribute to heavy metal pollution of the aquatic environment. Heavy metal ions, such as Zn2+, Cd2+, Pb2+and Cu2+, are difficult to be detected by olfaction and vision. Even at very low concentrations (10～100μg/L), heavy metal ions may present a serious hazard to humans, animals and plants. Some of them cannot be metabolized in vivo, which means that if they enter the human body, they won’t be degradable.Electrochemical stripping voltammetry (SV) and light addressable potentiometric sensor (LAPS), which is sensitive to certain ions particularly, are two most effective in situ methods to detect heavy metal ions in aqueous environment. These methods are adopted in this study, and their principles and quantitative skills are analyzed and illustrated. Moreover, new sensing materials, creative technology and automatic process of SV are studied. As the result, automatic seawater heavy ion monitor based on SV is developed and improved. In addition, research on micromation and integration for SV and LAPS is carried successively. A novel composite optoelectronic sensor array, which integrates micro electrode array (MEA) and micro LAPS sensors, is present accordingly. Besides, smart wireless heavy metal monitor system for aquatic environment is developed for Taihu Lake. This study is supported by the National High Technology Research Program (863Program) and the National Key Basic Research Program (973Program).The major work of this study is as follows:1) Homemade automatic seawater heavy ion monitor based on SV is developed and improved. Mercury-film glass-carbon electrode, as well as differential pulse stripping voltammetry (DPSV), is used to detect heavy metals ions as Zn2+, Cd2+, Pb2+and Cu2+. The accuracy and precision of the instrument are kept in±15～20%for seawater samples, and field tests in Bohai Sea are completed. To avoid using toxic mercury, bismuth-coated glass-carbon electrode is also tested.2) MEA, which is composed of multi micro electrodes, is developed and introduced. The MEA has good dimensional traits, and its voltammetric performance is confirmed to be satisfying by using cyclic voltammetric scan. The MEA are utilized to detect mixed samples as Pb2+and Cu2+,3) Smart voltammetric procedure is present to expand measurement range and improve measurement precision for MEA. The Smart voltammetric procedure has novel specialized features, such as system self-calibration, automatic measurement range, multi standard solution fluidics control and automatic deposition time adjustment.4) LAPS system based on precise light intensity modulation is presented to eliminate measurement error caused by fluctuation, distortion and noise of conventional light source output. Measurements for LAPS system based on precise light intensity modulation are given and show good results by comparing with system for conventional light source.5) A novel opto-electronic composite micro array is developed and studied. In this composite array, MEA and micro LAPS sensors are integrated. Based on this composite array, multi parameters can be detected simultaneously. Moreover, self-calibration model can be established by using multi parameters mentioned above. Measurement precision can be improved with the self-calibration model. Based on the composite array, wireless sensor network and internet of things, smart wireless monitor system for heavy metal is developed. Featured by advance fluidics design, smart voltammetric procedure, the system is suit for aquatic environment monitoring. |
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