Pyrolysis derivatization of humic substances 2. Pyrolysis of soil humic acids in the presence of tetramethylammonium hydroxide

Comparative study for separation of atmospheric humic-like substance (HULIS) by ENVI-18, HLB, XAD-8 and DEAE sorbents: Elemental composition, FT-IR, 1H NMR and off-line thermochemolysis with tetramethylammonium hydroxide (TMAH)

“…The aromatic compounds identified in HULIS were remarkably similar to pyrolysis products of HAs, FAs and lignin (Martin et al, 1994(Martin et al, , 1995del Rio et al, 1998;Chefetz et al, 2002;Li et al, 2006;Fukushima et al, 2011). All HULIS pyrograms present two distinct peaks at 32.8 min and 34.5 min (Nos.…”

A comparative study on the chemical composition of humic acids from forest soil, agricultural soil and lignite deposit

“…However, part of these materials escape degradation and can contribute to a significant fraction of humic substances (Cheshire, 1977;Anderson et al, 1989). Majority of studies examining lipid composition of humic acids have been concerned with soil and peat humic acids (Schnitzer and Ortiz de Serra, 1973;Saiz-Jimenez and de Leeuw, 1987;Hänninen and Niemala, 1991;Hänninen, 1992;Martin et al, 1995;del Rio et al, 1998;Grasset and Amblès, 1998a,b;Grasset et al, 2002). Similar studies about lignite humic acids are scarce (Gonzalez-Vila et al, 1996;Olivella et al, 2002;Rozenbaha et al, 2002).…”

Pyrolytic alkylation-gas chromatography-mass spectrometry of model polymers Further insights into the mechanism and scope of the technique

“…(TMAH) [1][2][3][4][5] and tetrabutylammonium hydroxide (TBAH) [6] has been introduced for the release of moieties bearing carboxyl groups from different polymers and macromolecules upon pyrolytic techniques. Use of the butylating reagent avoids one of the main limitations of pyrolytic methylation -its inability to distinguish between the methoxyl groups originally present in the macromolecule and the free hydroxyl groups that become methylated after the pyrolysis.…”