Study of the acid-base properties of fulvic acid-like substances extracted from senescent leaves of eucalyptus and oak

被引：3

作者：

Antelo, J ^{[1
]}

López, R ^{[1
]}

Fiol, S ^{[1
]}

Antelo, JM ^{[1
]}

Arce, F ^{[1
]}

机构：

[1] Univ Santiago de Compostela, Dept Quim Fis, Fac Quim, Santiago De Compostela 15782, Spain

来源：

ANALYTICAL AND BIOANALYTICAL CHEMISTRY | 2003年 / 375卷 / 04期

关键词：

senescent leaf extracts; fulvic acid; proton binding;

D O I：

10.1007/s00216-002-1726-8

中图分类号：

Q5 [生物化学];

学科分类号：

071010 ; 081704 ;

摘要：

The acid-base properties of two fulvic acids (FA) extracted from senescent leaves of eucalyptus and oak were characterized by carrying out potentiometric titrations at two FA concentrations and four ionic strengths (0.005 M <[KNO3] < 1.0 M). Experimental data were analyzed by means of the master curve approach, which includes an electrostatic spherical double layer model, and the Langmuir-Freundlich isotherm was used to fit the data. The contribution of the electrostatic effect to the proton binding reaction was lower than that observed for soil fulvic acids. The chemical heterogeneity of both samples was described by two acid sites with pKs of about 4 and 7.5, the most abundant being the carboxylic site of pK = 4.

引用

页码：523 / 526

页数：4

共 23 条

[1]

[Anonymous], 1994, HUMUS CHEM GENESIS C

[2]

BALDOCK JA, 1992, BIOGEOCHEMISTRY, V16, P1, DOI 10.1007/BF02402261

[3] INFORMATION PROVIDED ON HUMIC SUBSTANCES BY E4-E6 RATIOS [J].