The conformational structure of naturalorganic matterAlessandroPiccolo,Riccardo SpacciniPellegrino Conte,Danca Smeikalova,DonatoSannino,Antonio Nebbioso,Barbara FontaineDipartimento di Scienze del Suolo, della Pianta.dell Ambiente e delle Produzioni AnimaliUniversita di Napoli Federico ll
The conformational structure of natural organic matter Alessandro Piccolo, Riccardo Spaccini, Pellegrino Conte, Dan ča Smejkalova, Donato Sannino, Antonio Nebbioso, Barbara Fontaine Dipartimento di Scienze del Suolo, della Pianta, dell’Ambiente, e delle Produzioni Animali Università di Napoli Federico II
WHAT IS HUMIC MATTER?
WHAT IS HUMIC MATTER?
ISOLATIONANDPURIEICATIONPROCEDURESTOOBTAINHUMUCANDFULVIC ACIDSFROMSOILPreparation ofhumic acidandfuhvicacid samples (iHss method)SoilHAfractionFAfractionHCl-extractinO.1NKOHtreatwrithO.1NHCaddKcItoO.3NKcentrifugeOn XAD-8SoilHCl-extractSolutionppton XAD-8(add 0.1 M HCI and0.1N NaOHacidity (pH 1.0)centrifugewashing to neutral pH)centrifugeHA pptExtractSoil residueonXAD-8<in O.1N HCIbackeluterepeataocidity to pH 1.0+0.3NHFwith 0.1N NaOH2timescentrifugeHAFApptpH5with0.1HCIfractionfractiondialysisfreeze-dryfreeze-dryHumin fractionHAsampleFAsample
ISOLATION AND PURIFICATION PROCEDURES TO OBTAIN HUMIC AND FULVIC ACIDS FROM SOIL Humin fraction pH 5 with 0.1 HCl freeze-dry (add 0.1 M HCl and washing to neutral pH)
Humic substances (humic andfulvicacids)havebeen(10-500KDa),traditionallydescribedasmacropolymerssimilarly to biopolymers, and their synthesis was attributed toan extracellularenzymatic catalysis.The assumed monomer of such a humic macropolymer has beenfrom time to time described with a hypothetical structureaccording to the updating of new experimental results obtainedwith progressively more advanced analytical techniques.HC:OSugarHC-OHCOOHHC=OCOOHCOOHOH-0R-CHHOCOOHCH-CH2HOCOOHOHOHYNHOH1R-CH/C=O-NHStevenson,1982+
Humic substances (humic and fulvic acids) have been traditionally described as macropolymers (10-500 KDa), similarly to biopolymers, and their synthesis was attributed to an extracellular enzymatic catalysis. The assumed monomer of such a humic macropolymer has been from time to time described with a hypothetical structure according to the updating of new experimental results obtained with progressively more advanced analytical techniques. Stevenson, 1982
Such macropolymericCHalo-(CHa)theory of humicsubstances became anaccepted paradigm.(CHyOlo-3CHnOHA number of structures,[CHa]o-(CHa)either linear or(CHa/0-2branched, but allCH2OFstabilized by covalent(CHa)0(CHglo-bonds, have beenproposed and becamecommon in textbooksand scientific reports50nm
Such macropolymeric theory of humic substances became an accepted paradigm. A number of structures, either linear or branched, but all stabilized by covalent bonds, have been proposed and became common in textbooks and scientific reports