CARBOXYLIC-ACID CONTENT OF A FULVIC-ACID DETERMINED BY POTENTIOMETRY AND AQUEOUS FOURIER-TRANSFORM INFRARED SPECTROMETRY

被引：50

作者：

CABANISS, SE

机构：

[1] Chemistry Department, Kent State University, Kent

来源：

ANALYTICA CHIMICA ACTA | 1991年 / 255卷 / 01期

关键词：

INFRARED SPECTROMETRY; POTENTIOMETRY; CARBOXYLIC ACIDS; FULVIC ACID; WATERS;

D O I：

10.1016/0003-2670(91)85082-4

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

The carboxylic acid content of a fulvic acid is determined quantitatively using aqueous Fourier transform infrared spectrometry and potentiometry. The combined method minimizes interferences from other acidic or carbonyl functional groups in the fulvic acid mixture. Potentiometry alone provides only operational estimates of the acid content, which vary by up to 15% as the inert salt (sodium chloride) concentration increases from 1 to 500 mM. Quantitative IR spectra are collected in aqueous solutions of varying pH using an attenuated total reflectance cell designed for liquids. Changes in the area ratio of IR peaks due to protonated and deprotonated carboxylic acid groups correlate strongly (r2 = 0.995) with base consumed in potentiometric titrations. The carboxylic acid content of this fulvic acid is 9.09 +/- 0.28 (+/- 1 standard error) meq carboxylic acid per gram of carbon.

引用

页码：23 / 30

页数：8

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