NMR techniques (C, N, and H) in studies of humic substances

Este trabajo constituye el Capítulo 5 del libro.-- El DOI del volumen 651 es: 10.1021/bk-1996-0651.Nuclear magnetic resonance (NMR) spectroscopy has been used to characterize soil organic matter and study soil humification processes for nearly two decades, but only recently it has been considered a valuable analytical method in modern soil science. Technological and theoretical advances in the early development of NMR resulted in increased sensitivity and resolution of the NMR spectra of humic materials in soils. In turn, the increased utility of NMR led to the widespread initial use of this technique which is documented in the scientific literature by numerous NMR studies to obtain structural information on soil organic matter. Since those early applications spanning the 1970's and 1980's, a general hiatus has limited new developments in the field of soil science and the technique became routine in its application. Recently, some new applications involving isotope labeling combined with both 13C and 15N NMR has renewed interest in NMR as the premier technique for modern soil science research. This article reviews these recent developments.Peer reviewe