| Abstract | Brzina, preciznost i točnost analitičke metode u današnje vrijeme ključni su kriteriji za odabir tehnike kojom se karakterizira bilo koji matriks. Jedna takva metoda je prijenosna rendgenska fluorescencija (pXRF metoda), koja se uz već navedene kriterije odlikuje i mogućnošću istovremene analize većeg broja elemenata. Cilj ovoga diplomskog rada bio je utvrditi sadržaj metala (Fe, As, Cd, Cr, Co, Cu, Mn, Mo, Ni, Pb, Si, Sr, Zr, Th, U i Y) u trinaest komercijalnih mineralnih dušičnih gnojiva (različitih prema granulaciji i formulaciji dušika - NPK, urea, KAN, ASN) primjenom pXRF analizatora te utvrditi točnost (RPM) i preciznost (RSD) pXRF analize s obzirom na rezultate ostvarene primjenom klasičnih analitičkih metoda u dva referentna uzorka gnojiva (NPK+S i MF, BIPEA program). Detekcija i kvantifikacija metala provela se primjenom Vanta C (Olympus) pXRF analizatora u skladu s HRN ISO 13196:2015 normom. Rezultati ukazuju da je sadržaj promatranih elemenata u komercijalnim gnojivima varirao u rasponu od: 4 do 2209 mg Fe/kg, 1 do 8 mg As/kg, 12 do 31 mg Cd/kg, 7 do 119 mg Cr/kg, 2 do 26 mg Cu/mg, 97 do 5291 mg Mn/kg, 2 do 4 mg Mo/kg, 2 do 28 mg Ni/kg, 308 do 4581 mg Si/kg, 1 do 470 mg Sr/kg, 1 do 15 mg Zr/kg, 3 do 35 Th/kg, 1 do 83 mg U/kg te 1 do 128 mg Y/kg. Zadovoljavajuća preciznost mjerenja realnih uzoraka do dozvoljenih 25 % u svim analiziranim komercijalnim gnojivima utvrđena je za kvantificirani sadržaj željeza (RSD = 0-5 %), kadmija (RSD = 0-23 %), silicija (RSD = 1-13 %) i stroncija (RSD = 0-4 %). Sadržaj Cr, Mn, Fe, Cu i As precizno je utvrđen u NPK+S referentnom uzorku gnojiva, dok je detektirani sadržaj Fe i Ni bio u granicama prihvatljive točnosti metode (RPM < 25 %). U MF referentnom uzorku gnojiva preciznost utvrđenog sadržaja željeza i mangana bila je u zadovoljavajućem rasponu (RSD = 1-9 %) kao i zadovoljavajuća točnost metode kvantificiranog sadržaja mangana (RPM = 24 %). |
| Abstract (english) | Speed, precision and accuracy of any analytical method nowadays are the key criteria’s for choosing a technique for characterization of any matrix. One such method is the portable X-ray fluorescence (pXRF method), which, in addition to the already mentioned criteria, is characterized by the possibility of simultaneous analysis of a large number of elements. The aim of this thesis was to determine the content of metals (Fe, As, Cd, Cr, Co, Cu, Mn, Mo, Ni, Pb, Si, Sr, Zr, Th, U and Y) in thirteen commercial mineral nitrogen fertilizers (different due to granulation and nitrogen formulation - NPK, urea, LAN, ASN) using a pXRF analyzer and to determine the accuracy (RPM) and precision (RSD) of the pXRF analysis with regard to the results obtained using classical analytical methods in two reference fertilizer samples (NPK+S i MF, BIPEA program). Detection and quantification of metals was carried out by Vanta C (Olympus) pXRF analyzer in accordance with the HRN ISO 13196:2015 standard. The results indicate that the content of the observed elements in commercial fertilizers varied in the range of: 4 to 2209 mg Fe/kg, 1 to 8 mg As/kg, 12 to 31 mg Cd/kg, 7 to 119 mg Cr/kg, 2 to 26 mg Cu/mg, 97 to 5291 mg Mn/kg, 2 to 4 mg Mo/kg, 2 to 28 mg Ni/kg, 308 to 4581 mg Si/kg, 1 to 470 mg Sr/kg, 1 to 15 mg Zr /kg, 3 to 35 Th/kg, 1 to 83 mg U/kg and 1 to 128 mg Y/kg. Acceptable measurement precision of real samples up to the permitted 25 % in all analyzed commercial fertilizers was determined for the quantified content of iron (RSD = 0-5 %), cadmium (RSD = 0-23 %), silicon (RSD = 1-13 %) and strontium (RSD = 0-4 %). The content of Cr, Mn, Fe, Cu and As was precisely determined in the NPK+S reference fertilize sample, while the detected content of Fe and Ni was within the limits of acceptable accuracy of method (RPM < 25 %). In the MF reference fertilizer sample, precision of determined iron and manganese content was within acceptable range (RSD = 1-9 %), along with the acceptable accuracy of the method for the quantified manganese content (RPM = 24 %). |
