Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-...Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-destructive advantage, the EEM was applied to characterizing a commercial Fluka humic acid (FHA). The results showed that the EEMs of FHA has several Ex/Em peaks. Ionic strength (0- 0.05 mol/L KClO 4) exerted little effect on the fluorescence properties of FHA, while the concentrations (5-100 mg/L) of FHA and pH (2-12) had significant effects. A red shift in the longer wavelength peak region was observed when the concentrations or pH values increased. The fluorescence intensity increased with increasing pH, but slightly decreased in the case of pH= 5.0. The protonation constants (lgK’ HL) of peak B were calculated to be 3.57 and 3.13, indicating that peak B was due to carboxyl groups. The r (A/B) values range from 0.61 to 2.59. A strong linear relationship between r (A/B) and pH was also observed. This indicates that the fluorescence peaks A and B posses similar inherent fluorescence characteristics.展开更多
The membrane bioreactor(MBR)technology is a rising star for wastewater treatment.The pollutant elimination and membrane fouling performances of MBRs are essentially related to the dissolved organic matter(DOM)in the s...The membrane bioreactor(MBR)technology is a rising star for wastewater treatment.The pollutant elimination and membrane fouling performances of MBRs are essentially related to the dissolved organic matter(DOM)in the system.Three-dimensional excitation-emission matrix(3D-EEM)fluorescence spectroscopy,a powerful tool for the rapid and sensitive characterization of DOM,has been extensively applied in MBR studies;however,only a limited portion of the EEM fingerprinting information was utilized.This paper revisits the principles and methods of fluorescence EEM,and reviews the recent progress in applying EEM to characterize DOM in MBR studies.We systematically introduced the information extracted from EEM by considering the fluorescence peak location/intensity,wavelength regional distribution,and spectral deconvolution(giving fluorescent component loadings/scores),and discussed how to use the information to interpret the chemical compositions,physiochemical properties,biological activities,membrane retention/fouling behaviors,and migration/transformation fates of DOM in MBR systems.In addition to conventional EEM indicators,novel fluorescent parameters are summarized for potential use,including quantum yield,Stokes shift,excited energy state,and fluorescence lifetime.The current limitations of EEM-based DOM characterization are also discussed,with possible measures proposed to improve applications in MBR monitoring.展开更多
Hierarchical clustering analysis and principal component analysis （PCA） methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy （EEMs） data sets of sa...Hierarchical clustering analysis and principal component analysis （PCA） methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy （EEMs） data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter （DOM）. The distribution of different water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay.展开更多
The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ gr...The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ growth. To obtain a full picture of the whole set of endogenous fluorophores appearing in the gastrointestinal （GI） tumors investigated, the technique of excitation-emission matrix （EEM） development was applied in a broad spectral region, covering the ultraviolet and visible spectral ranges. We could thus address a set of diagnostically-important chromophores and their alterations during tumor develop- ment, namely, collagen, elastin, nicotinamide adenine dinucleotide （NADH）, flavins, porphyrins, while hemo- globin＇s absorption influence on the spectra obtained could be evaluated as well. Comparisons are presented between EEM data of normal mucosae, benign polyps and malignant carcinoma, and the origins are determined of the fluorescence signals forming these matrices.展开更多
文摘Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-destructive advantage, the EEM was applied to characterizing a commercial Fluka humic acid (FHA). The results showed that the EEMs of FHA has several Ex/Em peaks. Ionic strength (0- 0.05 mol/L KClO 4) exerted little effect on the fluorescence properties of FHA, while the concentrations (5-100 mg/L) of FHA and pH (2-12) had significant effects. A red shift in the longer wavelength peak region was observed when the concentrations or pH values increased. The fluorescence intensity increased with increasing pH, but slightly decreased in the case of pH= 5.0. The protonation constants (lgK’ HL) of peak B were calculated to be 3.57 and 3.13, indicating that peak B was due to carboxyl groups. The r (A/B) values range from 0.61 to 2.59. A strong linear relationship between r (A/B) and pH was also observed. This indicates that the fluorescence peaks A and B posses similar inherent fluorescence characteristics.
基金the National Natural Science Foundation of China(No.51778599)the Beijing Natural Science Foundation(No.LI82044)+1 种基金the CAS Strategic Priority Research Programmer(A)(No.XDA20050103)the Youth Innovation Promotion Association CAS(No.110500EA62)。
文摘The membrane bioreactor(MBR)technology is a rising star for wastewater treatment.The pollutant elimination and membrane fouling performances of MBRs are essentially related to the dissolved organic matter(DOM)in the system.Three-dimensional excitation-emission matrix(3D-EEM)fluorescence spectroscopy,a powerful tool for the rapid and sensitive characterization of DOM,has been extensively applied in MBR studies;however,only a limited portion of the EEM fingerprinting information was utilized.This paper revisits the principles and methods of fluorescence EEM,and reviews the recent progress in applying EEM to characterize DOM in MBR studies.We systematically introduced the information extracted from EEM by considering the fluorescence peak location/intensity,wavelength regional distribution,and spectral deconvolution(giving fluorescent component loadings/scores),and discussed how to use the information to interpret the chemical compositions,physiochemical properties,biological activities,membrane retention/fouling behaviors,and migration/transformation fates of DOM in MBR systems.In addition to conventional EEM indicators,novel fluorescent parameters are summarized for potential use,including quantum yield,Stokes shift,excited energy state,and fluorescence lifetime.The current limitations of EEM-based DOM characterization are also discussed,with possible measures proposed to improve applications in MBR monitoring.
基金supported by the National High-tech Research Project ("863" Project) of China under contract Nos 2003AA635180 and 2006AA09Z167the Public Welfare Project of Marine Science Research under contract No 200705011the open project of Key Laboratory of Integrated Marine Monitoring and Applied Technologies for Harmful Algal Blooms,SOA, China under contract No200811
文摘Hierarchical clustering analysis and principal component analysis （PCA） methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy （EEMs） data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter （DOM）. The distribution of different water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay.
文摘The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ growth. To obtain a full picture of the whole set of endogenous fluorophores appearing in the gastrointestinal （GI） tumors investigated, the technique of excitation-emission matrix （EEM） development was applied in a broad spectral region, covering the ultraviolet and visible spectral ranges. We could thus address a set of diagnostically-important chromophores and their alterations during tumor develop- ment, namely, collagen, elastin, nicotinamide adenine dinucleotide （NADH）, flavins, porphyrins, while hemo- globin＇s absorption influence on the spectra obtained could be evaluated as well. Comparisons are presented between EEM data of normal mucosae, benign polyps and malignant carcinoma, and the origins are determined of the fluorescence signals forming these matrices.
