magistrsko delo
Tamara Govejšek (Author), Matjaž Finšgar (Mentor), Ksenija Gradišek (Co-mentor)

Abstract

Namen magistrskega dela je optimizacija in validacija postopka določanja vsebnosti arzena (As) v titanovem dioksidu (TiO2) po popolnem razklopu z elektrotermično atomsko absorpcijsko spektrometrijo (ETAAS). V prvem delu smo izbrali način priprave preskusnih vzorcev, primeren za vse tipe pigmentnega TiO2 in določili optimalne pogoje izvajanja določitev As v preskusnih raztopinah z ETAAS. Zaprt mikrovalovni dvo-kislinski razklop je omogočal popoln razklop vseh tipov pigmentnega TiO2 brez izgub analita. Pri pogojih delovanja ETAAS smo izbrali količino preskusnega vzorca, vrsto kivete in določili tip in količino modifikatorja ter temperaturni program, ki je omogočal kontroliran nastanek prostih atomov As v stopnji merjenja absorbance brez izgub analita in brez spominskega efekta zaradi nepopolne odstranitve vzorca iz kivete po končani meritvi. Pirolitsko oplaščena grafitna kiveta s ploščico, uporaba modifikatorja Pd/Mg(NO3)2, temperatura sežiga (Tsežiga) 1000 °C, temperatura atomizacije (Tatomizacije) 2300 °C ter uporaba Zeemanove korekcije ozadja, so nam omogočile dovolj točne in natančne določitve As v koncentracijskem območju 1,0–50,0 mg/kg. Dosežena meja določljivosti (LOQ) postopka je bila 1,0 mg/kg. V koncentracijskem območju As 1,0¬¬–10,0 mg/kg smo dosegli natančnost, izraženo kot standardni odmik (s) ponovljivosti, ± 0,09 mg/kg, v območju 11,0–50,0 mg/kg pa kot relativni standardni odmik (RSD) ± 0,05 mg/kg. V celotnem območju določevanja je bila točnost izražena kot izkoristek 80–120 %. Cilj magistrske naloge je bil razviti postopek z mejo zaznavnosti (LOD) nižjo od 3 mg/kg, kar nam je uspelo.

Keywords

modifikatorji;grafitna kiveta s ploščico;titanov dioksid;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [T. Govejšek]
UDC: 543.632.472(043.2)
COBISS: 21791766 Link will open in a new window
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Downloads: 137
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Other data

Secondary language: English
Secondary title: Determination of arsenic in titanium dioxide
Secondary abstract: The purpose of the master thesis is optimization and validation of the procedure for determination of arsenic (As) in titanium dioxide (TiO2) after complete decomposition with electrothermal atomic absorption spectrometry (ETAAS). In the first part, we selected the method of preparing test samples suitable for all types of pigmented TiO2 under certain optimal conditions for performing determinations of As in the test solutions with ETAAS. The enclosed microwave digestion allowed the complete digestion of all types of pigmented TiO2 without the loss of analytes. Under the operating conditions of ETAAS, we selected the quantity of the test sample, the type of tube and the type and the amount of the modifier, and the temperature programme that allowed the controlled formation of free As atoms in the absorbance measurement rate, without the loss of analytes and no memory effect due to incomplete removal of the sample from the tube after measurement. A pyrolytically coated graphite tube with a platform, the use of the Pd/Mg(NO3)2 modifier, the ashing temperature of 1000 °C, the atomization temperature of 2300 °C and the use of the Zeeman background correction enabled accurate and precise determination of As in a concentration range 1,0–50,0 mg/kg. The limit of quantification (LOQ) process reached 1,0 mg/kg. In the concentration range 1,0–10,0 mg/kg, the accuracy expressed as the standard deviation (s) of repeatability is ± 0,09 mg/kg and relative standard deviation (RSD) is ± 0,05 mg/kg in the range 11,0–50,0 mg/kg. In the working dynamic range, the accuracy in terms of a recovery was always in the 80–120% interval. The aim of the master's thesis was to develop a process with a limit of detection (LOD) less than 3 mg/kg, which we succeeded.
Secondary keywords: modifier;graphite tube with a platform;titanium dioxide;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XIII, 58 str.
ID: 10941802