Pyrolysis–Gas Chromatography/Mass Spectrometry Identification of Distinctive Structures Providing Humic Character to Organic Materials

Abstract

Flash pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to study the structural transformations of humic fractions formed as a result of composting processes of diverse organic materials (solid wastes of wineries, solid olivemill wastes, domestic wastes, ovine manures plus straw, and mixtures of animal manures). Sodium hydroxide-extracted total humic-like extracts (THE; humic plus fulvic acids) from the composted and the initial noncomposted wastes and several reference humic and fulvic acids from soils were analyzed. Th ese results were compared with results from previous studies using 13 C-cross polarization magic angle spinning-nuclear magnetic resonance (NMR), UV-visible, and fl uorescence emission spectroscopies. Alkylbenzenes and alkylphenols predominate in the pyrograms of the soil humic acids, whereas the fulvic acids showed higher contents of phenolic and polysaccharide-derived compounds. Th e pyrolysates of THE from the composted samples showed an increase in aromatic and nitrogenated structures and a decrease in polysaccharidederived compounds. Th e aromatic contents as determined by Py-GC/MS and 13 C-NMR were well correlated in the reference humic substances and THE from composted materials (r = 0.99 and 0.94, respectively; P < 0.01) but not in the case of THE from noncomposted materials, probably due to an aliphatic enhancement in the pyrolysates of these samples and other secondary reactions. Th e content in alkylbenzenes was consistent with the variations found previously for several UVvisible and fl uorescence indexes as a function of the degree of humifi cation, suggesting their involvement in structures that are a characteristic feature of the formation and evolution of humic substances.

Rapid and Effective Isolation of Dissolved Organic Matter Using Solid-Phase Extraction Cartridges Packed with Amberlite XAD 8/4 Resins

“…AHA contained lignin, polysaccharides, protein, and polyhydroxy aromatic (PHA) fragments. These results were similar to those from previous research that reported that pyrolysis products of AHA included furans, pyrroles, phenols, benzenes, and alkanes, which are building blocks of biopolymers [23][24][25]. Since XAD 8 adsorbed more HPO substances than did XAD 4, In addition, XAD 4 also showed an order similar to the result of XAD 8 for the portion of adsorbed biopolymer (PHA > PS > protein, no lignin portion), even though the amount of adsorbed organic matter on XAD 4 was smaller than the amount of the adsorbed organic matter onto XAD 8 ( Table 2).…”

Amino Acids, Mineral Nutrients, and Efficacy of Vermicompost and Seafood and Municipal Solid Wastes Composts

“…These amino acids were part of the humic substances in the MSWC, SFWC, and the VC. The differences in the total and individual amino acid concentrations can be attributed to variations in the starting feedstock, the biodegradation process employed, the structure of the microbial community, and overall activities of hydrolyzing enzymes [23,24]. According to Fuentes et al [23], the composition of amino acids in compost may range between 4% and 20%.…”

“…The differences in the total and individual amino acid concentrations can be attributed to variations in the starting feedstock, the biodegradation process employed, the structure of the microbial community, and overall activities of hydrolyzing enzymes [23,24]. According to Fuentes et al [23], the composition of amino acids in compost may range between 4% and 20%. For instance, the three amino acids with the highest concentrations in the different types of organic amendments were glutamic acid (5.55-6.90 mg/g), aspartic acid (4.56-9.14 mg/g), and glycine (3.37-6.59 mg/g).…”

Changes in amino acids content of humic acids sequentially extracted from peat and sod–Podzolic soil

“…Several works (e.g. , Orlov 1990;Gonzalez-Vila et al 1994;Fuentes et al 2010) indicate humic compounds are mainly aromatic structures of phenolic, quinone and lignin type, and benzoic acid derivatives. Aromatic component in HA, including benzene carboxylic and phenoxy acids, can vary from 17 to 42% by sample mass depending on source and isolation procedure (Orlov 1990).…”

“…The AA constitute about 4Á20% of HA (Trubetskaya et al 1998;Fuentes et al 2010). Together with the peptides, AA take part in the complexation of metal ions, reactions with carbohydrates to form hydrogen bonds with carboxylic and hydroxyl groups of aromatic fragments, and in condensation reactions (Yamamoto and Ishiwatari 1992).…”