Validacija metode za določanje Zn(II), Cd(II) in Pb(II) z uporabo internega standarda : diplomsko delo univerzitetnega študijskega programa I. stopnje

Novak, Anže

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Title:	Validacija metode za določanje Zn(II), Cd(II) in Pb(II) z uporabo internega standarda : diplomsko delo univerzitetnega študijskega programa I. stopnje
Authors:	ID Novak, Anže (Author) ID Finšgar, Matjaž (Mentor) More about this mentor... ID Vrabelj, Tanja (Comentor)
Files:	UN_Novak_Anze_2020.pdf (2,87 MB) MD5: A32C551AEC8A59D70F19FE77E7067997 PID: 20.500.12556/dkum/ddfb9eef-ca8b-4d0f-ae22-f691177b2402
Language:	Slovenian
Work type:	Bachelor thesis/paper
Typology:	2.11 - Undergraduate Thesis
Organization:	FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:	Diplomsko delo predstavlja delno validacijo metode za določanje Zn(II), Cd(II) in Pb(II) v sledovih z uporabo modifikatorja in internega standarda Bi(III). Za izvajanje elektrokemijskih meritev smo uporabili modificirano delovno elektrodo iz steklastega ogljika z Bi-prevleko (tvorjena in-situ), Ag/AgCl(nasičen KCl) referenčno elektrodo ter platinasto žičko kot pomožno elektrodo. Elektrokemijske meritve smo izvedli s square-wave anodno stripping voltametrijo, kjer smo z namenom izboljšanja natančnosti in točnosti metode ter doseganja širšega linearnega koncentracijskega območja uporabili signal modifikatorja kot signal internega standarda. V okviru delne validacije metode smo določili meje zaznavnosti in meje določljivosti na podlagi razmerij signal/šum, ki sta znašali 3,8 μg/L in 5,7 μg/L za Zn(II), 0,8 μg/L in 2,7 μg/L za Cd(II) ter 0,4 μg/L in 1,2 μg/L za Pb(II). Linearna koncentracijska območja metode smo določili brez in z upoštevanjem signala za interni standard. Ugotovili smo, da metoda z upoštevanjem signala internega standarda v primerjavi z metodo brez upoštevanja le-tega razširi koncentracijsko linearno območje za vse analizirane ione. Točnost smo preverjali z določevanjem koncentracije analitov z uporabo metode večkratnega standardnega dodatka, kjer smo ugotovili, da je metoda z uporabo internega standarda Bi(III) pokazala slabšo točnost za Zn(II) in Cd(II), kot v primerjavi z metodo brez upoštevanja le-tega. Za Pb(II) ion smo opazili obraten trend vpliva internega standarda, saj se je točnost metode z njegovo uporabo izboljšala. Pri preverjanju natančnosti metode smo ugotovili, da je uporaba Bi(III) vplivala na izboljšanje natančnosti za vse tri analite.
Keywords:	anodna stripping voltametrija, elektroda iz steklastega ogljika, analiza težkih kovin, interni standard
Place of publishing:	Maribor
Place of performance:	Maribor
Publisher:	[A. Novak]
Year of publishing:	2020
Number of pages:	IX, 28 str.
PID:	20.500.12556/DKUM-77074
UDC:	543.552(043.2)
COBISS.SI-ID:	32448003
NUK URN:	URN:SI:UM:DK:D5SB0MIP
Publication date in DKUM:	09.10.2020
Views:	1423
Downloads:	246
Metadata:
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:	14.08.2020

Secondary language

Language:	English
Title:	Method validation for Zn(II), Cd(II) and Pb(II) determination using internal standard.
Abstract:	The thesis presents a partial method validation for trace Zn(II), Cd(II), and Pb(II) determination using Bi(III) as the electrode modifier and as the internal standard. For electrochemical measurements, a modified Bi-film glassy carbon working electrode (formed in-situ), an Ag/AgCl(saturated KCl) reference electrode, and a platinum wire counter electrode were employed. Electrochemical measurements were performed by square-wave anodic stripping voltammetry, using a signal for the modifier as the signal of the internal standard to improve the accuracy and precision of the method and to achieve a wider linear concentration range. Within the partial method validation, the limits of detection and the limits of quantification were determined based on the signal-to-noise ratio to be 3.8 μg/L and 5.7 μg/L for Zn(II), 0.8 μg/L and 2.7 μg/L for Cd(II) and 0.4 μg/L and 1.2 μg/L for Pb(II). The linear concentration ranges of the method were determined without and with consideration of the signal of the internal standard. We found that the method using the signal of the internal standard widens the linear concentration range for all analytes compared with the method without considering the internal standard. Accuracy was checked by concentration determination of the analytes using the multiple standard addition method. We found that the method using the internal standard Bi(III) showed lower accuracy for Zn(II) and Cd(II) compared with the method without consideration of the internal standard. For the Pb(II) ion, we observed an opposite trend of the internal standard influence, where the accuracy of the method was improved by using the internal standard. Moreover, the precision of the method using the Bi(III) signal as the internal standard was improved for all three analytes.
Keywords:	anodic stripping voltammetry, glassy carbon electrode, heavy metal analysis, internal standard

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