Surface-enhanced Raman spectroscopy of chernozem humic acid and their fractions obtained by coupled size exclusion chromatography-polyacrylamide gel electrophoresis (SEC-PAGE)

• Published in: Applied spectroscopy Vol. 60; no. 1; p. 48
• Main Authors: Sanchez-Cortes, S, Corrado, G, Trubetskaya, O E, Trubetskoj, O A, Hermosin, B, Saiz-Jimenez, C
• Format: Journal Article
• Language: English
• Published: United States 01.01.2006
• Subjects: Chemical Fractionation - methods; Chromatography, Gel - methods; Electrophoresis, Polyacrylamide Gel - methods; Humic Substances - analysis; Russia; Spectrum Analysis, Raman - methods; Surface Properties; Russia
• ISSN: 0003-7028
• DOI: 10.1366/000370206775382695

A humic acid extracted from a chernozem soil was fractionated combining size exclusion chromatography and polyacrylamide electrophoresis (SEC-PAGE). Three fractions named A, B, and C+D, with different electrophoretic mobilities and molecular sizes (MS), were obtained and subsequently characterized by thermochemolysis and surface-enhanced Raman spectroscopy (SERS). The data confirmed that fraction A, with the higher MS, was more aliphatic than fractions B and C+D and, in turn, fractions with lower MS (B and C+D) denoted an enrichment in lignin residues. These structural features explain conformational changes when varying the pH in the humic fraction A and indicated that combination of the two techniques is a good approach for characterizing humic substances.