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Title:Optimizacija sestave in situ elektrode in metode za izboljšanje analitske učinkovitosti določanja kovin v sledovih : magistrsko delo
Authors:Jezernik, Klara (Author)
Finšgar, Matjaž (Mentor) More about this mentor... New window
Petovar, Barbara (Co-mentor)
Files:.pdf MAG_Jezernik_Klara_2021.pdf (6,21 MB)
MD5: 3C78B0FA1BE5FDF07C2D4CDFF3858F18
 
Language:Slovenian
Work type:Master's thesis/paper (mb22)
Typology:2.09 - Master's Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Magistrsko delo prikazuje študijo delne validacije, določanje vpliva spremenljivk in optimizacijo analizne metode za elektrokemijsko določitev Zn(II), Cd(II) in Pb(II) v sledovih s tehniko ang. square wave anodne striping voltametrije. Vpliv spremenljivk smo določili v skladu z zasnovanim delnim dvonivojskim petfaktorskim eksperimentalnim načrtom. Optimizacijo smo izvedli z algoritmom Simpleks, pri čemer smo spreminjali čas in potencial elektrodepozicije ter masne koncentracije Bi(III), Sn(II) in Sb(III) ionov, ki so se uporabili za zasnovo modificirane in situ elektrode iz steklastega ogljika. V uporabljenem optimizacijskem kriteriju so bili združeni parametri, s katerimi se oceni analitska učinkovitost metode (širina linearnega koncentracijskega območja, LOQ, občutljivost, točnost in natančnost metode). Slednje je prav tako služilo kot odziv v eksperimentalnem načrtu. Z eksperimentalnim načrtom smo določili vpliv spremenljivk na preiskovan eksperimentalni sistem in zagotovili zadostno število eksperimentov za pričetek optimizacije sistema. Na podlagi optimizacijskega kriterija smo pri optimizaciji Simpleks določili optimalno elektrodo pri potencialu elektrodepozicije –1,380 V vs Ag/AgCl in času elektrodepozicije 100 s ter masnih koncentracijah Bi(III) 1,00 mg/L, Sn(II) 0,60 mg/L in Sb(III) 0,34 mg/L. Pri enakih pogojih smo primerjali analitsko učinkovitost optimalne in situ elektrode s tremi elektrodami, pri katerih smo za zasnovo in situ elektrode uporabili le eno vrsto ionov kovine. Ugotovili smo, da je izmed teh elektrod optimalna in situ elektroda najbolj primerna za simultano določitev Zn(II), Cd(II) in Pb(II), zato smo jo uporabili za določitev Zn(II), Cd(II) in Pb(II) v realnem vzorcu pitne vode. Določili smo tudi vpliv različnih interferentov, ki so lahko prisotni v vzorcu pitne vode, pri čemer sta na določitev analitov najbolj vplivala Cu(II) in Fe(II).
Keywords:square wave anodna striping voltametrija, elektroanaliza težkih kovin, delna validacija analizne metode, eksperimentalni načrt, optimizacija Simpleks
Year of publishing:2021
Place of performance:Maribor
Publisher:[K. Jezernik]
Number of pages:XVI, 75 str.
Source:Maribor
UDC:543.552:543.3(043.2)
COBISS_ID:72417795 New window
NUK URN:URN:SI:UM:DK:IB3ZYGPV
Views:125
Downloads:24
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:KTFMB - FKKT
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:22.05.2020

Secondary language

Language:English
Title:Optimisation of the in situ electrode composition and methods for improving the analytical efficiency of trace metals determination
Abstract:In this master's thesis the study of partial method validation, the impact of variables and the optimisation of an analytical method for electrochemical trace determination of Zn(II), Cd(II) and Pb(II) by using squarewave anodic stripic voltammetry were detailed. The influence of the variables was determined in accordance with the designed partial two-level five-factor experimental design. The optimization was performed using the Simplex algorithm. The time of electrodeposition, the potential of electrodeposition and mass concentrations of Bi(III), Sn(II) and Sb(III), which were used to design the modified in situ glassy carbon electrode, were changed. The optimisation criterion combined the parameters which were used to evaluate the analytical efficiency of the method (the width of the linear concentration range, LOQ, sensitivity, accuracy and precision of the method). The latter also served as a response in the experimental design. By using the experimental design the influence of the variables on the investigated system was studied which also provided the necessary number of experiments to start the system optimisation. Based on the Simplex optimisation criterion the optimal electrode was determined at an electrodeposition potential of –1.380 V vs Ag/AgCl, an electrodeposition time of 100 s and mass concentrations of 1,00 mg/L for Bi(III), 0,60 mg/L for Sn(II) and 0,34 mg/L for Sb(III). The analytical efficiency of the optimal in situ electrode was compared with three electrodes, in which only one metal ion type was used for the design of the in situ electrode. The optimal in situ eletrode was determined to be the most suitable for the simultaneous determination of Zn(II), Cd(II) and Pb(II), therefore, it was used for the analysis of tap water to determine Zn(II), Cd(II) and Pb(II). The influence of different interferences which could be present in drinking water was evaluated. The greatest influence on the determination of the analytes was determined to be the presence of Cu(II) and Fe(II).
Keywords:square wave anodic stripping voltammetry, electroanalysis of heavy metals, partial method validation, experimental design, Simplex optimisation


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