Reusability of SPE and Sb-modified SPE Sensors for Trace Pb(II) Determination

Abstract

In this work, unmodified screen-printed electrode (bare SPE) and Sb-film modified SPE (SbFSPE) sensors were employed for the analysis of trace amounts of Pb(II) in non-deaerated water solutions. The modified electrode was performed in situ in 0.5 mg/L Sb(III) and 0.01 M HCl. The methodology was validated for an accumulation potential of –1.1 V vs. Ag/AgCl and an accumulation time of 60 s. A comparative analysis of bare SPE and SbFSPE showed that the detection and quantification limits decrease for the bare SPE. The method with the bare SPE showed a linear response in the 69.8–368.4 µg/L concentration range, whereas linearity for the SbFSPE was in the 24.0–319.1 µg/L concentration range. This work also reports the reason why the multiple standard addition method instead of a linear calibration curve for Pb(II) analysis should be employed. Furthermore, the analytical method employing SbFSPE was found to be more accurate and precise compared to the use of bare SPE when sensors were employed for the first time, however this performance changed significantly when these sensors were reused in the same manner. Furthermore, electrochemical impedance spectroscopy was used for the first time to analyse the electrochemical response of sensors after being used for multiple successive analyses. Surface characterisation before and after multiple successive uses of bare SPE and SbFSPE sensors, with atomic force microscopy and field emission scanning electron microscopy, showed sensor degradation. The interference effect of Cd(II), Zn(II), As(III), Fe(II), Na(I), K(I), Ca(II), Mg(II), NO3–, Bi(III), Cu(II), Sn(II), and Hg(II) on the Pb(II) stripping signal was also studied. Finally, the application of SbFSPE was tested on a real water sample (from a local river), which showed high precision (RSD = 8.1%, n = 5) and accurate results.

The Use of Factorial Design and Simplex Optimization to Improve Analytical Performance of In Situ Film Electrodes

“…The simplex optimization procedure did not have a significant influence on the LOD and LOQ for these in situ FEs. These values were in the same range as reported previously [ 22 , 24 , 39 ].…”

“…The simplex optimization procedure did not have a significant influence on the LOD and LOQ for these in situ FEs. These values were in the same range as reported previously [22,24,39]. The LOD is the lowest concentration where the signal can be confidently distinguished from the noise, and the LOQ is the lowest concentration at which quantification is possible.…”

“…The simplex optimization procedure did not have a significant influence on the LOD and LOQ for these in situ FEs. These values were in the same range as reported previously [22,24,39]. The precision of the system is reported in Table 5 as the RSD obtained for 12 consecutive measurements of the Zn(II), Cd(II), and Pb(II) stripping signals (peak heights) in the same solution.…”

“…The simplex optimization procedure did not have a significant influence on the LOD and LOQ for these in situ FEs. These values were in the same range as reported previously [22,24,39]. As mentioned above, sensitivity was evaluated based on the calibration curve's slope.…”

Trace Voltammetric Determination of Lead at a Recycled Battery Carbon Rod Electrode

“…Alternative techniques such as anodic stripping voltammetry have also been employed, but have suffered from the use of relatively large amounts of Hg required for their application. However, a number of Hg-free devices have been reported, made possible by either the in situ or ex situ deposition of other less toxic metal films, such as Bi [ 10 ], Sb [ 11 ] or, more recently, Cu [ 12 ] and Sn [ 13 ]. Nevertheless, some disadvantages of the application of metal film-based electrodes have been highlighted [ 14 ].…”