Study On Rapid Measurement Of Bacteria In Water By Multi-Wavelength Transmission Spectroscopy

Bacterial contamination is a serious environmental problems which the security of drinking water faced in China.The existing detection methods are relatively accurate,but the sample has to be intermittently collected.The experiment process is cumbersome and time-consuming,and unable to meet the fast,real-time and on-line detection of bacteria in water.In this paper,Escherichia coli,Staphylococcus aureus and Klebsiella pneumoniae which were commonly appeared in water were researched.The research focused on obtaining the multi-wavelength transmission spectra of bacteria in water and the quantitative detection capabilities of multi-wavelength transmission spectra on measuring bacteria and microbes in water.The main research results as followed:(1)Multi-wavelength transmission spectroscopy rapid measurement experiment system establishment:Based on the deuterium lamp and the bromine tungsten lamp as the light source and the multi-channel grating spectrometer as the spectral detection device,the experimental system of rapid measurement of the multi-wavelength transmission spectra of the water bacterial microbes was established and optimized.Based on standard materials(potassium dichromate and filter)and the measurement results of ultraviolet and visible spectrophotometer,the spectral calibration and data analysis of the experimental system were carried out.The results show that the linear correlation coefficient of the different concentration of potassium dichromate solution and the neutral filter with different transmittance between the experimental system and the ultraviolet and visible spectrophotometer is less than 0.99 and the error is less than 5%.The system has the advantages of high measurement speed,high sensitivity and good stability,which validated the accuracy of spectrum measured by the experimental system.The experimental system has better accuracy of spectral measurement.(2)Rapidly and accurately obtained the multi-wavelength transmission spectrum of bacteria:Escherichia coli,Staphylococcus aureus and Klebsiella pneumoniae were used as experimental subjects.The transmission spectra of three kinds of bacteria were measured over a broad range of transmission wavelengths(220?900nm)by the experimental system and the ultraviolet and visible spectrophotometer,and the measurement results are compared and analyzed.The results showed that the linear correlation coefficient of the multi-wavelength transmission spectra of the three kinds of bacteria was more than 0.99,and the spectral consistency was better.The single measurement time of the average transmission spectrum of bacteria measured by the system was 15s,which was 30 times of the signal acquisition,far less than the single spectra measured by ultraviolet and visible spectrophotometer.(3)Preliminary analysis of quantitative detection ability of bacteria:Escherichia coli,Staphylococcus aureus and Klebsiella pneumoniae were used as experimental subjects.Based on the spectral data measured by experimental system and ultraviolet and visible spectrophotometer,the detection limits of three bacteria obtained from different wavelength and full spectral bands of the multi-wavelength transmission spectra are compared and analyzed.The results showed that the detection limits of the three kinds of bacteria are better than those of the ultraviolet and visible spectrophotometer,and the detection limits of the three kinds of bacteria calculated by the full spectra of the multi-wavelength transmission spectra are 1.16×104,1.06×104 and 1.60×104 cells/ml.In this paper,the experimental system realized the fast,accurate and highly sensitive acquisition of multi-wavelength spectrum of bacteria in water.And based on the full spectrum,the results of the quantitative detection and analysis of bacteria in water were better.It provides an important technical means for the development of real time,on-line monitoring and early warning system of bacteria.