TY - JOUR
T1 - Structural changes in a dissolved soil humic acid during photochemical degradation processes under O2 and N2 atmosphere
AU - Schmitt-Kopplin, Philippe
AU - Hertkorn, Norbert
AU - Schulten, Hans Rolf
AU - Kettrup, Antonius
PY - 1998/9/1
Y1 - 1998/9/1
N2 - Irradiation (UV/Vis λ > 290 nm) under nitrogen and oxygen atmosphere significantly affected the structure of dissolved humic material (DHM). Photobleaching of the DHM solution occurred essentially under O2 atmosphere in conjunction with a decrease in average molecular weight and an increase in acidity due to the disaggregation and photooxidation processes. The structural changes were followed by various separation and analytical methods including capillary zone electrophoresis (CZE), gel permeation chromatography (GPC), Fourier transformation infrared (FTIR), and one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR) as well as pyrolysis-field ionization mass spectrometry (Py-FIMS). The structural investigations showed selective degradation of DHM, especially under oxygen atmosphere. Structures of lignic and lipidic origin were the most photolabile as compared to carbohydrates, alkylbenzenes, or N-containing structures that accumulated in the system. Under nitrogen atmosphere the acids remained fairly stable. Indirect photolysis seems to be the major pathway in degradation of DHM subjected to UV/Vis irradiation.
AB - Irradiation (UV/Vis λ > 290 nm) under nitrogen and oxygen atmosphere significantly affected the structure of dissolved humic material (DHM). Photobleaching of the DHM solution occurred essentially under O2 atmosphere in conjunction with a decrease in average molecular weight and an increase in acidity due to the disaggregation and photooxidation processes. The structural changes were followed by various separation and analytical methods including capillary zone electrophoresis (CZE), gel permeation chromatography (GPC), Fourier transformation infrared (FTIR), and one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR) as well as pyrolysis-field ionization mass spectrometry (Py-FIMS). The structural investigations showed selective degradation of DHM, especially under oxygen atmosphere. Structures of lignic and lipidic origin were the most photolabile as compared to carbohydrates, alkylbenzenes, or N-containing structures that accumulated in the system. Under nitrogen atmosphere the acids remained fairly stable. Indirect photolysis seems to be the major pathway in degradation of DHM subjected to UV/Vis irradiation.
UR - http://www.scopus.com/inward/record.url?scp=0032167543&partnerID=8YFLogxK
U2 - 10.1021/es970636z
DO - 10.1021/es970636z
M3 - Article
AN - SCOPUS:0032167543
SN - 0013-936X
VL - 32
SP - 2531
EP - 2541
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 17
ER -