title: Optimization of conditions for high-performance size-exclusion chromatography of different soil humic acids.
abstract: A method of high-performance size-exclusion chromatography (HPSEC) for a wide variety of soil humic acids (HAs) was developed. Two types of soil HAs (Cambisol and Andosol HAs), which have substantially different chemical properties, showed different effects of salt and organic solvent concentrations in the eluent on chromatograms. A Shodex OHpak SB-805 HQ column with 10 mM sodium phosphate buffer (pH 7.0) containing 25% of acetonitrile (v/v) was found to be applicable for different HAs, and showed high reproducibility and recovery (87.0 - 94.5%). The Cambisol HA was fractionated into five fractions using an ultrafiltration with different molecular-weight cut-offs. The order of the molecular weights of the five fractions calculated from the HPSEC analysis corresponded to that defined by ultrafiltration. This supported the reliability of the method.
authors.affiliation: The Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Asakawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Kiyota
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Yanagi
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Fujitake
mesh_terms: D002138:Calibration; D002850:Chromatography, Gel / Q000379:methods*; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D015203:Reproducibility of Results; D012965:Sodium Chloride; D012987:Soil / Q000032:analysis*; D012997:Solvents; D014462:Ultrafiltration
chemical_list: D006812:Humic Substances; D012987:Soil; D012997:Solvents; D012965:Sodium Chloride