Određivanje elementnog sastava ljuštura školjaka metodom XRF

master's thesis

• Title (english): Determination of elemental content of bivalve shells using XRF method
• Author: Igor Jambrešić
• Mentor: Sanda Rončević (mentor)
• Committee member: Sanda Rončević (predsjednik povjerenstva)
• Committee member: Mirta Rubčić (član povjerenstva)
• Committee member: Đani Škalamera (član povjerenstva)
• Committee member: Iva Juranović Cindrić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-01-25, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Kamenice i kunjke su jestivi školjkaši koji nastanjuju hrvatsku obalu te se često koriste za određivanje polutanata u moru radi svoje građe koja im omogućuje akumulaciju teških metala iz antropogenih izvora onečišćenja. Prednost analize ljuštura nad tkivom je ta da se na taj način dobiju informacije o dugoročnim varijacijama u okolišu dok analiza tkiva daje samo trenutačne koncentracije metala. Načini na koje se metali mogu vezati na školjke građene prvenstveno od aragonita i kalcita su taloženje metala na površinu kalcijeva karbonata i zamjena iona metala s kalcijem. Uređaj koji se koristio za analizu školjaka u ovom radu je prijenosni analizator XRF koji nudi gotove kalibracijske opcije. Kako bi se validirala metoda, analiza je provedena na standardnim smjesama CaCO3 i uzoraka školjaka s dodatkom oksidnih i nitratnih soli Zn, Ni, Cu, Pb, Cd i Cr. Izračunati parametri (RE, MAPE, MAE, t-test) ukazuju na to da je metoda pogodna za analizu ovog tipa uzorka, no pošto uređaj ima ograničen broj kalibracijskih opcija dobiveni se rezultati moraju korigirati. Kao rješenje ovog problema navodimo kreiranje novih kalibracijskih opcija ili mogućnost samostalne kalibracije od strane korisnika.

Abstract (english)

Oysters and Noah's Ark shells are edible bivalves that live on Adriatic shore and are often used for determination of pollutants that are present in the sea because of their structure, which enables them to accumulate heavy metals from anthropogenic sources. Main advantages of analyzing shells over tissue is that it gives information about accumulated concentration of metals in bivalves. Some of the ways in which metals can be incorporated into shells, which are primarily made of aragonite and calcite, are precipitation of metals onto surface of calcium carbonate and substitution of calcium cation with other metals. Instrument that was used to analyze shells was portable XRF analyzer which has factory-calibrated modes. To validate analytical method, we also analyzed standard mixtures of CaCO3, and shell sample mixed with oxide and nitrate salts of Zn, Ni, Cu, Pb, Cd and Cr. Calculated parameters (RE, MAPE, MAE, t-test) indicate that this method is good for analysis of this type of samples. However, it has limited number of factory-calibrated modes, which showed that results need to be corrected. As a solution of this problem, we propose that manufacturers generate new calibration modes and program their instruments with option to calibrate instrument using standard samples.

• Keywords: XRF; školjke; teški metali; MAPE
• Keywords (english): XRF; bivalve; heavy metals; MAPE
• Language: croatian
• URN:NBN: urn:nbn:hr:217:162791
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-01-25
• Created on: 2023-02-07 16:35:13