Title Ekstrakcija organske faze tla Title (english) Extraction of soil organic matter Author Grazia Milovan Mentor Mirna Petković-Didović (mentor)Committee member Dalibor Broznić (predsjednik povjerenstva)Committee member Marin Tota (član povjerenstva)Committee member Mirna Petković-Didović (član povjerenstva)Granter University of Rijeka Defense date and country 2022-09-30, Croatia Scientific / art field, BIOMEDICINE AND HEALTHCARE Scientific / art field, BIOTECHNICAL SCIENCES Scientific / art field, NATURAL SCIENCES Scientific / art field, INTERDISCIPLINARY AREAS OF KNOWLEDGE Abstract Alkalna ekstrakcija organske faze tla postupak je star gotovo 150 godina. Unatoč tome što je osnovno načelo uvijek isto, postoje brojne metode alkalne ekstrakcije, koje se međusobno razlikuju po jednoj ili više varijabli.
U ovom su istraživanju korištena tri tla s različitih lokacija – Slavonska crnica (SC), Bukva Zlobin (BZ) i Plasa Bor (PB). Tla su podvrgnuta alkalnoj ekstrakciji organske faze tla na tri načina. Načini se međusobno razlikuju po vrsti kiseline (sumporna i klorovodična) koja je korištena za zakiseljavanje i krajnjem pH do kojeg se zakiseljavalo (pH 7 odnosno pH 2). Kemijski sastav alkalnih ekstrakata ispitivan je novijom metodom FTIR spektrometrije, tj. metodom prigušene totalne refleksije (engl. Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy, ATR-FTIR), kako bi se utvrdilo utječe li – i na koji način – promjena varijabli tijekom ekstrakcije na kemijski sastav alkalnih ekstrakata. Analiza je upotpunjena ATR-FTIR analizom organske faze cjelovitih tala, analizom mineralne faze, elementarnom (CHN) analizom, te spektrofotometrijskim određivanjem količine organske faze. Dodatni cilj rada bio je utvrditi praktičnost i primjenjivost ATR-FTIR spektrometrije za kemijsku analizu tla.
Rezultati su pokazali da odabir kiseline (sumporna/klorovodična) ne utječe na kemijski sastav alkalnih ekstrakata, dok krajnji pH zakiseljavanja jest utjecajan čimbenik. Ekstrakcijom pri pH 7, ekstrakti su sadržavali značajne količine mineralne faze. U ekstraktima dobivenima ekstrakcijom pri pH 2, količina mineralne faze smanjila se, ali je i dalje bila prisutna. ATR-FTIR spektri mineralne faze bili su skladu s prethodno određenim teksturalnim sastavom tala, i pokazali su se nužnima za točnu analizu ATR-FTIR spektara ekstrakata i cjelovitih uzoraka tla. Analizom spektara ekstrakata utvrđeno je da je kemijski sastav organske faze PB i BZ tla gotovo identičan, s huminskim kiselinama kao dominantnom komponentom. Ekstrakti SC tla sadržavali su veći udio fulvinskih kiselina. Ovakvi rezultati pokazuju da ATR-FTIR tehnika, u svom osnovnom obliku, može na brz, jednostavan i jeftin način dati korisne informacije o kvalitativnoj analizi tla, ali za kvantitativnu, detaljnu i preciznu analizu nužno ju je upotpuniti drugim komplementarnim tehnikama.
Abstract (english) Alkaline extraction of soil organic matter (SOM) is an ancient procedure, almost 150 years old. Despite the fact that the basic principle remains unaltered, there are multiple methods of alkaline extraction differing among themselves in one or more variables.
In this research, we used three soils from different locations, onto which we employed three different methods of alkaline extraction. The methods differ in acids used for acidification (sulphuric vs. hydrochloric) and the final pH down to which the acidification was performed (pH 7 vs. pH 2). Chemical composition of the extracts was analysed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), in order to establish whether – and how – the changes in extraction variables affect the chemical composition of alkaline extracts. The analysis is supplemented by ATR-FTIR analysis of the pristine soil samples, mineral phase analysis, elemental (CHN) analysis, and by spectrophotometric determination of SOM quantity. The additional goal of the study was to examine the practicality and usefulness of ATR-FTIR technique in soil analysis.
The results showed that the choice of acid does not influence the chemical composition of the extracts, while the final acidification pH does. The extracts obtained by pH7-extraction contained significant amounts of mineral phase. In extracts obtained by pH2-extraction, the amount of mineral phase diminished, but it was still present. ATR-FTIR spectra showed good correlation with previously determined textural analysis of soils, and they proved to be very useful for accurate analysis of extracts’ spectra. The analysis of extracts’ spectra showed that the chemical composition of PB’s and BZ’s extracts are virtually identical, containing predominantly humic acids. On the other hand, SC extracts contained higher amount of fulvic acids. These results demonstrate that ATR-FTIR, in its basic form, can provide useful information for qualitative soil analysis in a fast, simple and affordable manner, but for quantitative, detailed and precise analysis, it should be supplemented with other complementary techniques.
Keywords
organska tvar tla (SOM)
ekstrakcija
prigušena totalna refleksija (ATR-FTIR)
Keywords (english)
soil organic matter (SOM)
extraction
attenuated total reflectance (ATR-FTIR)
Language croatian URN:NBN urn:nbn:hr:184:063296 Study programme Title: Study of Sanitary Engineering Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2022-09-29 11:08:43
