The Optical Inspection Method Of Trace Toxic Organic Pollutants And Instrument Study

The application of pesticide promoted the development of modern agriculture. However, along with the continuous increase of variety and quantity, the pollution which pesticides have brought about has done serious damage to people, livestock, environmental biotechnology and environmental factors such as water, atmosphere and soil. Though pesticide residues are trace components, they can also do great harm to mankind's live and health if people have contact with them for a long time. Therefore it becomes exceptional important to detect pesticide and their metabolites sensitively.First the article introduced basic principle of fluorescence analysis method, established the mathematical model for pesticide solution concentration and fluorescence intensity, analyzed the condition of material to be able to produce fluorescence ,and the influence of environmental factor to the fluorescence characteristic influence.Then,the article introduced conventional analysis and familiar fluorescence analysis method,studied fluorescence spectrum of water and methyl alcohol through experiment, confirmed that they can be used as background solvent, surveyed two kind of typical pesticides fluorescence spectra, obtained their optimal excitation wavelength, also studied the influence of solution PH value to the fluorescence signal simultaneously.The article has designed one kind of fluorescence optical fiber measurement system for rudimental pesticides which carries on the quantitative analysis to rudimental pestide.According to pesticides fluorescence characteristic,designed optical system about stimulation,receivation and transmission of fluorescence. The system take the pulse xenon lamp to as excitation light source, phase step refractivity quartz fiber as transmission fiber.With interference filter the system can achieve selection for excitation wavelength range and the emission wavelength range of pesticides,with convex lens carry out coupling of optical fiber and source. The system uses flat field holographic concave gating spectrograph to carry on dispersion and focusing to fluorescence,the fluorescence signal enter array CCD through coupling,array CCD transforms the fluorescence signal to the electrical signal. After amplifying and filtering signal export to the A/D converter which convert analog signal into the digital signal evacuation as the input signals of DSP,and finally serially output the computer to carry on further processing and the demonstration.Optical part of system uses design method of the double path of rays,the signal examination part uses the double channel detection technique,to eliminate disturbance of excitation light and the transmission path rays as well as the noise of photoelectric detection device.According to the linear relations of pesticide concentration and fluorescence intensity,have determined the method of working curve.