TECHNICAL NOTE Stripping analysis of heavy metals in tap water using the bismuth film electrode Núria Serrano & José Manuel Díaz-Cruz & Cristina Ariño & Miquel Esteban Received: 2 October 2009 / Revised: 3 November 2009 / Accepted: 3 November 2009 / Published online: 24 November 2009 # Springer-Verlag 2009 Abstract A commercially available screen-printed carbon electrode coated with an ex situ deposited bismuth film (BiSPCE) has been applied to the determination of Pb(II) and Zn(II) ions in tap water (Barcelona water distribution network) by means of stripping voltammetry (SV) and stripping chronopotentiometry (SCP). A good reproducibil- ity of the measurements and a satisfactory agreement between SV and SCP data were observed for both heavy metal ions. Although, in principle, the procedure could be also suited to the determination of Cd(II), this species was not detected. The results were also consistent with the routine ICP-OES measurements of the water distribution company, thus confirming the potential usefulness of such BiSPCE disposable devices for the analysis of heavy metals in natural waters. Keywords Bismuth film screen-printed carbon electrode . Ex situ deposition . Constant-current stripping chronopotentiometry . Stripping voltammetry . Heavy metals in tap water Introduction The term heavy metal is often used as a group name for metals and semimetals (metalloids) that have been associ- ated with contamination and potential toxicity or ecotox- icity [1], although certain heavy metals (e.g., Co, Cr, Cu, Mo, Mn, Ni and Zn) are essential for healthy life in small or trace quantities. This is not the case of non-essential trace metals (mainly Cd, Pb and Hg), which do not have any known biological function. Heavy metals, which enter the human body through food, water, air or absorption through the skin when they come in contact with human activities, become toxic when they are not metabolized by the body and accumulate in the soft tissues [2]. Atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and stripping techniques (anodic stripping voltammetry (ASV) and stripping chro- nopotentiometry (SCP)) are the available techniques for the determination of heavy metals in natural water samples. Stripping techniques are particularly suitable for the determination of trace metals in samples of environmental and biological origin [3], due to their excellent detection limits, their sensitivity to the presence of different metal species, their capacity to multielement determination, and their relatively low cost. For several decades, mercury electrodes have been the most used working electrodes for electroanalytical purposes (stripping techniques among them) due to their wide cathodic range [4]. Nowadays, the development of alterna- tive materials, with less toxicity and more environmentally friendly than mercury, is a subject of research. Many studies have demonstrated the applicability of bismuth film electrodes (BiFE) and antimony film electrodes (SbFE) as a possible alternative for electrochemical stripping analysis of trace heavy metals, with electroanalytical behavior similar to that of mercury-based electrodes. In the 1990s, the first adaptation of screen-printed technology for the stripping analysis of trace metals was described [5–7]. As a result of this development, the use7 of thick-film screen-printed electrodes for the electro- N. Serrano (*) : J. M. Díaz-Cruz : C. Ariño : M. Esteban Departament de Química Analítica. Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain e-mail: nuria.serrano@ub.edu Anal Bioanal Chem (2010) 396:1365–1369 DOI 10.1007/s00216-009-3294-7