Fractionation of natural organic matter in drinking water and characterization by 13C cross-polarization magic-angle spinning NMR spectroscopy and size exclusion chromatography.
Natural organic matter from drinking water sources was fractionated, and the fractions were characterized by NMR and SEC with the aim of relating NOM structure to treatability. Organic matter was isolated from two Australian surface waters (Horsham, Moorabool) by reverse osmosis and from a groundwater (Wanneroo) by anion exchange. The isolates were fractionated according to polarity and charge by resin adsorption. 13C NMR spectra of the freeze-dried fractions showed the most hydrophobic fraction to be high in aliphatic and aromatic carbon while slightly hydrophobic organics have more carbonyl and alkoxyl carbon. The Horsham and Wanneroo hydrophilic fractions show strong alkoxyl signals attributed to carbohydrate. Moorabool hydrophilics contain aromatic (phenolic) carbon; the apparent absence of carbohydrate appears to be an artifact. Size-exclusion chromatograms were recorded on the original and fractionated organics with both UV and dissolved organic carbon detection. The Horsham and Moorabool organics have similar molecular size distributions while Wanneroo is dominated by strongly absorbing species having large hydrodynamic radii. The hydrophobic and charged hydrophilic fractions also have high apparent MW, while the neutral fraction is higher in low-MW compounds of relatively low specific absorbance, suggestive of carbohydrates.
Wong
S
S
Institut für Polymerforschung, Dresden, Germany.
Hanna
J V
JV
King
S
S
Carroll
T J
TJ
Eldridge
R J
RJ
Dixon
D R
DR
Bolto
B A
BA
Hesse
S
S
Abbt-Braun
G
G
Frimmel
F H
FH
D002241:Carbohydrates / Q000032:analysis; D002247:Carbon Isotopes; D002850:Chromatography, Gel; D004784:Environmental Monitoring / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009930:Organic Chemicals / Q000032:analysis*; D014881:Water Supply
D002241:Carbohydrates; D002247:Carbon Isotopes; D009930:Organic Chemicals