Analysis of trace heavy metals in a sample droplet with lab-on-a-chip systemNika Žurga
, 2020, diplomsko delo
Opis: 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
Objavljeno: 31.08.2020; Ogledov: 275; Prenosov: 83
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