Determination of Pb(II) with a dithizone-modified carbon paste electrode.
ABSTRACT A dithizone (DTZ) modified carbon paste electrode was developed for the sensitive and selective determination of Pb(II) using differential pulse anodic stripping voltammetry as well in batch as in FIA system. The analysis procedure is based on an open circuit accumulation step in a stirred sample solution. This was followed by a medium exchange to a clean solution and subsequently by a proper anodic stripping. The analytical performance was evaluated with respect to the quantity of modifier in the paste, accumulation time, background electrolyte, Pb(II) concentration and other variables. When the accumulation time applied was 5 minutes, linear calibration graphs were obtained in the concentration range 1 x 10(-7)-1 x 10(-5) M and 8 x 10(-8)-5 x 10(-6) M for batch and Flow Injection Analysis (FIA), respectively. The detection limits found were 8.65 x 10(-8) M in batch and 4.45 x 10(-8) M in FIA. A convenient and rapid renewal of electrode surface allows the use of a single modified electrode surface in multiple analytical determinations. Several coexisting metals ions such as Cd(II), Hg(II), Cu(II) and Zn(II) had no interference on the determination of Pb(II). The proposed method was applied in the determination of lead in soils located in the vicinity of metallurgic transformation industry. The results obtained were in accordance to the ones supplied by Atomic Absorption Spectroscopy (AAS).
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ABSTRACT: This study reports the electrochemical modification of glassy carbon (GC) surface with etodolac (ETO), the characterization of this ETO modified glassy carbon (ETO/GC) electrode and its electroanalytical application for the determination of Pb(II) ions. Binding type of the etodolac with the glassy carbon surface was investigated and found that it was through the etheric linkage revealed from the reflection-absorption infrared spectroscopy (RAIRS). The ETO/GC electrode was characterized by cyclic voltammetry (CV), reflection-adsorption IR spectroscopy, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The ETO/GC electrode was found to be suitable for selective determination of Pb(II) by adsorptive stripping voltammetry in the solutions of the mixture of heavy metal ions, such as Cu(II) and Cd(II) and showed high stability and reproducibility. The stability and the potential range of the ETO/GC electrode were also studied. The developed method was validated according to the ICH guideline and found to be linear, sensitive, selective, precise and accurate. The linearity range of Pb(II) was 5.0 x 10(-10) to 1.0 x 10(-8) M with the detection limit (S/N = 3) of 1.67 x 10(-10) M. The validated method was applied successfully for the determination of Pb(II) in real samples. (c) 2012 Elsevier B.V. All rights reserved.Sensors and Actuators B Chemical 08/2012; 171-172:1207-1215. DOI:10.1016/j.snb.2012.06.082 · 3.84 Impact Factor
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ABSTRACT: A stable and sensitive biosensor for phenol detection based on a screen printed electrode modified with tyrosinase, multiwall carbon nanotubes and glutaraldehyde is designed and applied in a flow injection analytical system. The proposed carbon nanotube matrix is easy to prepare and ensures a very good entrapment environment for the enzyme, being simpler and cheaper than other reported strategies. In addition, the proposed matrix allows for a very fast operation of the enzyme, that leads to a response time of 15 s. Several parameters such as the working potential, pH of the measuring solution, biosensor response time, detection limit, linear range of response and sensitivity are studied. The obtained detection limit for phenol was 0.14 x 10(-6) M. The biosensor keeps its activity during continuous FIA measurements at room temperature, showing a stable response (RSD 5%) within a two week working period at room temperature. The developed biosensor is being applied for phenol detection in seawater samples and seems to be a promising alternative for automatic control of seawater contamination. The developed detection system can be extended to other enzyme biosensors with interest for several other applications.Nanotechnology 06/2010; 21(24):245502. DOI:10.1088/0957-4484/21/24/245502 · 3.67 Impact Factor
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ABSTRACT: In this review (with 500 refs), both electrochemistry and electroanalysis with carbon paste-based electrodes, sensors, and detectors are of interest, when attention is focused on the research activities in the years of new millennium. Concerned are all important aspects of the field, from fundamental investigations with carbon paste as the electrode material, via laboratory examination of the first electrode prototypes, basic and advanced studies of various electrode processes and other phenomena, up to practical applications to the determination of inorganic ions, complexes, and molecules. The latter is presented in a series of extensive tables, offering a nearly complete survey of methods published within the period of 2001–2008. Finally, the latest trends and outstanding achievements are also outlined and future prospects given.Central European Journal of Chemistry 12/2009; 7(4):598-656. DOI:10.2478/s11532-009-0097-9 · 1.33 Impact Factor