New study of anion-exchange chromatography for profiling of soil and peat humic substances and aromatic carboxylic acids

Abstract

A simple anion-exchange liquid chromatographic method has been developed to assay commercial
available humic substances, alkaline extracts of various types of soils and selected model aromatic
acids. The anion-exchange HPLC analysis used short glass column (30x3 mm) filled with Separon
HEMA-BIO 1000 sorbent with (diethylamino)ethyl functional groups (60 μm particles) and a mobile
phase A constituted of aqueous solution of tetrasodium salt of EDTA (pH 12.0; 5 mmol L-1) and
mobile phase B constituted of aqueous solution of tetrasodium salt of EDTA (pH 12.0, 500 mmol L-1).
The wavelength of the detection is 480 nm (ex) and 530 nm (em) for humic substances and soils and
280 nm for aromatic acids. The proposed method provided an accurate and precise analysis of
commercial available humic substances, alkaline extracts of various types of soils and selected
aromatic acids. It was experimentally proved that under the selected conditions model aromatic acids
are separated according to increasing effective negative charge and by analogy we suppose the same
separation model also for fulvic acids and humic acids.