title: Alkaline hydrolysis of humic substances--spectroscopic and chromatographic investigations.
abstract: To find out more on the structure of humic substances (HS), isolated dissolved organic carbon (DOC) samples from a brown water lake and a wastewater effluent were fractionated and subjected to alkaline hydrolysis. UV/Vis and fluorescence spectroscopy, as well as size-exclusion chromatography with on-line detection of UV absorption, fluorescence and DOC concentration were used to investigate the structural changes caused by the hydrolysis reaction. Following hydrolysis, the fluorescence intensity increased considerably despite a decrease in the UV absorption. The UV absorption and the DOC data from the SEC experiments revealed a strong shift to smaller molecular sizes after hydrolysis. The spectra of the hydrolysed samples, as well as the size-exclusion chromatograms, were compared to spectra of hydroxybenzoic acids and hydroxycinnamic acids. From this comparison, it can be concluded that the hydrolysis products have a structure similar to these organic acids.
authors.affiliation: Division of Water Chemistry, Engler-Bunte-lnstitut, University of Karlsruhe, Germany.
authors.forename: M U
authors.initials: MU
authors.lastname: Kumke
authors.forename: C H
authors.initials: CH
authors.lastname: Specht
authors.forename: T
authors.initials: T
authors.lastname: Brinkmann
authors.forename: F H
authors.initials: FH
authors.lastname: Frimmel
mesh_terms: D000042:Absorption; D002845:Chromatography; D006812:Humic Substances / Q000737:chemistry*; D006868:Hydrolysis; D010100:Oxygen / Q000032:analysis; D013050:Spectrometry, Fluorescence; D014466:Ultraviolet Rays; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D006812:Humic Substances; D014873:Water Pollutants; D010100:Oxygen