Diffusion coefficients and polydispersities of the Suwannee River fulvic acid: Comparison of fluorescence correlation spectroscopy, pulsed-field gradient nuclear magnetic resonance, and flow field-flow fractionation

被引:129
作者
Lead, JR
Wilkinson, KJ
Balnois, E
Cutak, BJ
Larive, CK
Assemi, S
Beckett, R
机构
[1] Univ Geneva, CABE, CH-1211 Geneva 4, Switzerland
[2] Univ Kansas, Dept Chem, Lawrence, KS 66045 USA
[3] Monash Univ, CRC Freshwater Ecol, Water Studies Ctr, Clayton, Vic 3800, Australia
[4] Monash Univ, Dept Chem, Clayton, Vic 3800, Australia
关键词
D O I
10.1021/es991195h
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
Diffusion coefficients of the Suwannee River fulvic acid (SRFA) obtained using fluorescence correlation spectroscopy (FCS), pulsed-field gradient nuclear magnetic resonance spectroscopy (PFG-NMR), and flow field-flow fractionation (FIFFF) were compared as a function of pH (4.0-8.5) and ionic strength (5-500 mM). Diffusion coefficients of the SRFA ranged between 1.9 and 3.5 x 10(-10) m(2) s(-1). These values were fairly constant as a function of both pH and ionic strength and comparable to the limited literature values available. Polydispersity data are shown indicating that there is some degree of size and chemical heterogeneity for this humic sample including a small fraction of SRFA components with a diffusion coefficient smaller than I x 10(-1)0 m(2) s(-1). The results imply that the majority of SRFA components have hydrodynamic diameters between 1.5 and 2.5 nm.
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页码:3508 / 3513
页数:6
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