The Study Of Micro Photo-electricity System For Environmental Monitoring

With the development of science and rapid step of the industrialization, our environment has been unprecedented damage, especially the water environment. The study of a monitoring system based on microfluidic chip will help the real-time water quality monitoring in order to find out pollutant sources in time, to identify contaminated areas and the type of pollution and to determine the emergency treatment. The domestic research on this topic is still at the initial stage. Even in the worldwide, the lab research is a mainstream. The monitoring microfluidic chips developed mostly suffer high requirements for optical system, and complicated process, and costly. They are a far from application.By comparing the advantages and disadvantages of water quality monitoring techniques, a universal optical detection method is adopted for microscale photoelectric detection system, which monitoring the concentration of heavy metal zinc ion for the first step.The measurement is based on the theory of substance absorbency and the intensity modulation method is used to realize. By checking the change of light intensity, the concentration of the pending liquor can be detected. The experimental results show the microscale photoelectric detection system works well.The new microscale photoelectric detection system and circuits are designed. The detecting pool is made up by a capillary tube of 400μm inner diameter and 32mm channel length. The light emitting is LED, a PV is for light receiving. A rectifier filter circuit is arranged for the light emitting diode stable power supply, and two LM358 chips are to achieve the detection signal amplification.The experiments utilize a given wavelength (535nm) to detect the light loss. By averaging several repeat measurements, the concentration of the solution can be determined. Finally, the relationship of the concentration and the light loss is obtained.The micro photo-electricity system shows well performance in the detection of the zinc ion concentration of solution samples. The whole system is light, cheap and portable and furthermore, it has many advantages such as few optical elements, high measurement accuracy, structure simplicity, small volume, etc. It is a potential microscale monitoring system for water quality.It is also available for gas intensity measurements.