Analysis of trace heavy metals in a sample droplet with lab-on-a-chip system

diplomsko delo univerzitetnega študijskega programa I. stopnje

Nika Žurga (Avtor), Matjaž Finšgar (Mentor), Barbara Petovar (Komentor)

Povzetek

The aim of this work was to develop and validate an electroanalytical method for simultaneous determination of Zn(II), Cd(II), and Pb(II) in a sample droplet with lab-on-a-chip system. Unmodified screen-printed electrodes (bare SPE using Ag/AgCl reference electrode) and Bi-film SPEs (BiFSPE) were used as electrochemical sensors. Cyclic voltammetry of [Fe(CN)6]3–/[Fe(CN)6]4– redox couple was employed for testing the reversibility of the diffusion-controlled system and square-wave anodic stripping voltammetry (SWASV) for determination of Zn(II), Cd(II), and Pb(II). SWASV was performed at deposition potential of –1.5 V vs. Ag/AgCl and deposition time of 60 s. The following validation parameters were examined: limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, and precision. LOD and LOQ for Zn(II) were both lower with BiFSPE than with bare SPE. For Cd(II), LOD and LOQ were similar for both bare SPE and BiFSPE. For Pb(II), LOD and LOQ with bare SPE could not be determined (due to intense background contribution) but were obtained with BiFSPE. Linear concentration ranges were obtained for all analytes with bare SPE and BiFSPE. Accuracy and precision were evaluated for different spiked concentrations; however, the method with bare SPE was neither accurate nor precise. With BiFSPE, the method was found to be both accurate and precise for Pb(II) at a spiked concentration of 140.0 μg/L, but not for Zn(II) or Cd(II). For the latter, problems with accuracy and precision were encountered with both bare SPE and BiFSPE. Both methods were selective for Zn(II), Cd(II), and Pb(II) determination. It can be concluded that the optimization of both methods is required for future studies.

Ključne besede

SPE;BiFSPE;heavy metals determination;SWASV;validation;

Podatki

Jezik:	Angleški jezik
Leto izida:	2020
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[N. Žurga]
UDK:	543.2:549.25(043.2)
COBISS:	27647491
Št. ogledov:	551
Št. prenosov:	122
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarni naslov:	Analiza sledov težkih kovin v kapljici vzorca s sistemom laboratorija na čipu
Sekundarni povzetek:	Namen diplomskega dela je bil razvoj in validacija elektroanalizne metode za simultano določevanje Zn(II), Cd(II) in Pb(II) v kapljici vzorca s sistemom laboratorija na čipu. Kot elektrokemijski senzor smo uporabili nemodificiran SPE-senzor (angl. screen-printed electrode) z Ag/AgCl referenčno elektrodo in senzor SPE, modificiran s tanko plastjo bizmuta (BiFSPE). Reverzibilnost sistema, ki je difuzijsko kontroliran, smo preverjali s ciklično voltametrijo redoks para [Fe(CN)6]3–/[Fe(CN)6]4–. Za določevanje Zn(II), Cd(II) in Pb(II) smo uporabili tehniko square-wave anodno striping voltametrijo (SWASV) pri potencialu nalaganja –1,5 V vs. Ag/AgCl in času nalaganja 60 s. V sklopu validacije smo preverjali mejo zaznavnosti, mejo določljivosti, linearnost, točnost in natančnost. Meja zaznavnosti in meja določljivosti za Zn(II) sta bili nižji pri uporabi BiFSPE v primerjavi s SPE. Za Cd(II) sta bili meja zaznavnosti in meja določljivosti podobni za SPE in BiFSPE. Mej zaznavnosti in določljivosti za Pb(II) z uporabo SPE ni bilo mogoče določiti zaradi intenzivne bazne linije, medtem ko smo ju z BiFSPE lahko določili. S SPE in tudi z BiFSPE smo določili linearna koncentracijska območja za vse tri analite. Točnost in natančnost smo preverjali za več koncentracij analitov, vendar se je metoda s SPE izkazala za netočno in nenatančno. Metoda z BiFSPE za koncentracijo 140,0 μg/L je bila točna in natančna za določevanje Pb(II), vendar ne za Zn(II) in Cd(II). Za slednja so se pojavljale težave s točnostjo in natančnostjo, tako za SPE kot tudi za BiFSPE. Obe metodi sta selektivni za določanje Zn(II), Cd(II) in Pb(II). Zaključimo lahko, da je za nadaljnje študije potrebna nadaljnja optimizacija obeh metod.
Sekundarne ključne besede:	težke kovine;validacija;določevanje težkih kovin;elektroanalizne metode;diplomske naloge;
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	IX, 33 str.
ID:	11956773