University of Zagreb. Faculty of Science. Department of Chemistry.
Abstract
Analitičke spektrometrijske metode temeljene na plazma izvorima (ICP-AES i ICP-MS) omogućuju
multielementnu kvantitativnu karakterizaciju različitih materijala. Pouzdanost mjerenih koncentracija elemenata
uvelike ovisi o mogućim interferencijama matrice koje mogu biti spektralne i/ili nespektralne. Materijali kojima
je glavni konstituent željezo, a sadržavaju brojne analite u niskom koncentracijskom području, ubrajaju se u
analitički zahtjevne uzorke. Pri elementnom profiliranju ovih materijala nužno je utvrditi osjetljivost određivanja
i opseg interferencija koje potječu od željeza.
U ovom radu određivani su elementni profili arheoloških uzoraka iz proizvodnje spužvastog željeza i
uzoraka neutralnih nanočestica željeza metodom ICP-AES. Izbor emisijskih linija slobodnih od interferencija
utvrđen je nakon studije utjecaja matrice na modelnoj otopini i realnoj matrici željezovih meteorita. Korekcijom
pozadinskog zračenja razlučeni su osjetljivi signali linija prijelaznih metala, lantanoida i odabranih polumetala
koji su poslužili u elementnom profiliranju uzoraka.
Uzorci iz arheometalurgijske proizvodnje željeza dodatno su karakterizirani metodama XRF i SEM-EDS.
Prošireni skup mjerenih podataka o koncentracijama elemenata podvrgnut je kemometrijskoj obradi.
Multivarijatnim statističkim metodama (PCA, HAC) dobivene su jasne razlike u skupini nehomogenih materijala
što je omogućilo klasifikaciju uzoraka u skupine materijala šljake, proizvedenog željeza i ishodne rude.
Uzorcima sintetiziranih nanočestica željeza određena je čistoća metodom ICP-AES pri prethodno
definiranim mjernim uvjetima. Pripravljene neutralne nanočestice željeza (nZVI) karakterizirane su i metodama
SEM-EDS, XRD, TGA i IR. Ispitane su mogućnosti metode ICP-AES za praćenje sorpcije metala na sintetiziranim
nanočesticama. Pri tome je detaljnije ispitano uklanjanje kroma (VI) u niskom koncentracijskom području iz
vodenih otopina. Rezultati pokazuju da se uzorci s visokim udjelima željeza, uz odgovarajući izbor linija analita i
korekcije spektralne pozadine, mogu uspješno analizirati metodom ICP-AES. Elementni profili materijala dodatno
su upotpunjeni informacijama izvedenim pri kombiniranju više spektroskopskih metoda i kemometrijskih alata.Analytical spectrometry methods based on plasma source (ICP-AES, ICP-MS) enable multi-elemental
quantitative characterization of various materials. Reliability of measured elemental concentrations strongly
depends on spectral and/or non-spectral matrix interferences. Iron-based materials that contain numerous analites
at trace concentration level are representatives of extremely demanding analytical samples. The estimation of
magnitude of interferences and sensitivity of determination are prerequisites in elemental profiling of such kind of
material. In this work, the elemental profiles of archaeological samples from an early-iron production along with
samples of iron nanoparticles were analysed by ICP-AES method. The selection of emission lines that are free
from interferences was performed after testing of matrix effects. For this purpose the model solutions and real
sample matrix, which consists of solution of iron meteorites, were used. By background emission correction, the
sensitive emission lines of transition metals, lanthanides and selected semi-metals were selected for the purpose
of elemental profiling of samples. Archaeometallurgical samples from bloom iron production were characterized
by XRF and SEM-EDS methods, additionally. The extended range of obtained elemental concentrations was
subdued to chemometric processing. Multivariate statistical analysis (PCA, HCA) has showed clear discernment
between samples of inhomogeneous material. It provided classification of examined samples on groups, such as
bloom iron, ceramic rich slag and ore material. DrThe purity of synthesized iron nanoparticles was determined by
ICP-AES method using the adjusted operational parameters. The prepared zero-valent iron nanoparticles (nZVI)
were also characterised using SEM-EDS, XRD, TGA and IR methods. The capability of ICP-AES method in
tracking of metal sorption on prepared nanoparticles was examined. In particular, the removal of chromium (VI)
at low levels from aqueous solutions was emphasized. The results show that high content iron samples were
successfully analysed by ICP-AES method after proper line selection and applied background corrections. In
addition, the elemental profiles of samples were complemented by information that were gained through
combination of spectroscopy and chemometric methods
