Study On High-volume Seawater Enriching And Detecting System

The typical persistent organic pollutants in seawater, especially the Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), are paid more and more attention of the researchers on marine environment to, because of their poison, persistence, enrichment and distance transmission and other characteristics, which demands regular monitor to ensure the quality of the sea water. However, these pollutants are too diluted in the seawater, which makes necessary preliminary sample preparation before being analyzed. Therefore, it is essential to research and develop an apparatus to treat huge work of sample preparation automatically before being analyzed.Based on the phase extraction, sol-gel technology, capillary enrichment theory and the relative theories, the dissertation designs a sample pretreatment system applied to trace organic pollutants in seawater. An on-line concentration device is placed in the apparatus, which successfully combines sampling of high-volume and high-speed seawater and a small volume injection into analyzing apparatuses, and an on-line enrichment and detection system is designed and produced based on that, which can effectively solve the existing issues, such as high-volume and high-speed sampling, time-consuming analyzing procedure, laborious operation, and unavailable real-time analysis and monitor. The apparatus is modularized and it consists of sampling, enrichment, washing down, on-line concentration, automatic injection or gathering and isolation monitor and the relevant, which are relatively independent and can be combined for the fulfillment of different functions based on the needs.The control system adopts master-slave double-layer structure and distributed control method, the upper computer employs the embedded industrial control unit PC104plus as the core, with the micro control unit as the lower level control to perform the operation automatically. And the lower level control can perform some tasks independently, and following the instructions of the upper computer. The whole control system consists of two parts, one to control transfer liquid and gas flow and the run or stop sequence control of pumps and valves; the other to monitor and control the flow rate, temperature and pressure. RS232 and RS485 are used to complete the communication between lower level devices and upper computer.Experimental tests show that the system has the ability to complete huge sample pretreatment process automatically. Preceded by the fulfillment of the basic functions of the apparatus, the stability, anti-jamming, and ship-carried electronic equipment anti-vibration of the system are researched to make preparation for the further research.