Lead determination was carried out in the frame of the European Union project Biocop (www.biocop.org) using a bismuth-modified screen-printed electrode (Bi-SPE) and the stripping analysis technique. In order to choose a sensitive Bi-SPE for lead detection, an analytical comparative study of electrodes modified by Bi using "in situ", "ex situ" and "bulk" procedures was carried out. On the basis of the results obtained, we confirmed that the "in situ" procedure resulted in better analytical performances with respect to not only "ex situ" but also to "Bi2O3 bulk" modified electrodes, allowing for a linear range of lead ion concentration from 0.5 to 100 mu g L-1 and a detection limit of 0.15 mu g L-1. We demonstrated that, before the Bi film deposition, an oxidative electrochemical pre-treatment of the working electrode could be useful because it eliminates traces of lead in the graphite-ink, as shown with stripping measurements. It also improves the electrochemical performance of the electrodes as demonstrated with Electrochemical Impedance Spectroscopy (EIS) measurements. The influence of different analytical parameters, such as the electrolyte solution composition (acetate buffer, chloridric acid, nitric acid, perchloric acid) and the ionic strength was investigated in order to evaluate how to treat the sample before the analysis. The morphology of prepared "in situ" Bi-SPEs was also characterized by Atomic Force Microscopy (AFM). Finally, the Bi-SPEs were used to determine the concentration of lead ions in tap and commercial water samples obtaining satisfactory values of the recovery percentage (81% and 98%). (C) 2011 Elsevier BM. All rights reserved. RI Moscone, Danila/E-5404-2012; Li Destri, Giovanni/C-8807-2012; Punzo, Francesco/A-4921-2011 OI Li Destri, Giovanni/0000-0001-6195-659X; Punzo, Francesco/0000-0003-4212-8064
Part I: A comparative study of bismuth-modified screen-printed electrodes for lead detection
PUNZO, FRANCESCO;LI DESTRI NICOSIA, GIOVANNI
2011-01-01
Abstract
Lead determination was carried out in the frame of the European Union project Biocop (www.biocop.org) using a bismuth-modified screen-printed electrode (Bi-SPE) and the stripping analysis technique. In order to choose a sensitive Bi-SPE for lead detection, an analytical comparative study of electrodes modified by Bi using "in situ", "ex situ" and "bulk" procedures was carried out. On the basis of the results obtained, we confirmed that the "in situ" procedure resulted in better analytical performances with respect to not only "ex situ" but also to "Bi2O3 bulk" modified electrodes, allowing for a linear range of lead ion concentration from 0.5 to 100 mu g L-1 and a detection limit of 0.15 mu g L-1. We demonstrated that, before the Bi film deposition, an oxidative electrochemical pre-treatment of the working electrode could be useful because it eliminates traces of lead in the graphite-ink, as shown with stripping measurements. It also improves the electrochemical performance of the electrodes as demonstrated with Electrochemical Impedance Spectroscopy (EIS) measurements. The influence of different analytical parameters, such as the electrolyte solution composition (acetate buffer, chloridric acid, nitric acid, perchloric acid) and the ionic strength was investigated in order to evaluate how to treat the sample before the analysis. The morphology of prepared "in situ" Bi-SPEs was also characterized by Atomic Force Microscopy (AFM). Finally, the Bi-SPEs were used to determine the concentration of lead ions in tap and commercial water samples obtaining satisfactory values of the recovery percentage (81% and 98%). (C) 2011 Elsevier BM. All rights reserved. RI Moscone, Danila/E-5404-2012; Li Destri, Giovanni/C-8807-2012; Punzo, Francesco/A-4921-2011 OI Li Destri, Giovanni/0000-0001-6195-659X; Punzo, Francesco/0000-0003-4212-8064I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.