Exposure to lead, a toxic heavy metal, in drinking water is a worldwide problem. Lead leaching from lead service lines, the main contamination source, and other plumbing materials is controlled...

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Bimetallic oxide nanoparticles are promising materials due to their diverse physical properties. Herein, we synthesized bimetallic aluminum oxides (AlOx)- iron oxides (FeOx) nanoparticles with different shapes and elemental compositions by...

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Nowadays lead pipes are still present in many houses and could be a potential source of this metal in drinking water. Modern polyvinyl chloride pipes also contain compounds of lead, that can be leached from them, causing an increase of Pb concentration in drinking water. That is why regular and simple testing of tap water is necessary to avoid lead poisoning. Voltammetric sensors, due to their high sensitivity, simplicity and low cost, are very good for the detection of lead ions. In tap water, except of free ions, lead may present in various particulate forms (i.e. oxides, hydroxide, insoluble salts, etc.) that cannot be detected directly using electrochemical techniques. A user-friendly sensor should exclude any sample preparation; however, this step is necessary to bring all the species to the ionic form. It has been reported the possibility of electrochemical pH reduction of water. Oxidation of water occurs easily on most inert electrodes (Pt, Au, etc.), producing hydrogen ions. Generated H+ can chemically interact with some lead species, revealing free lead ions. The proposed method employs electrochemical generation of hydrogen ions, combined with stripping square wave voltammetry for quantification of lead species in particulate form, using lead carbonate as a model compound. The signal obtained using this method is linearly proportional to the amount of solid PbCO3 added to the solution in the range of 50-250 μg/l.

Sensitive element of hydrogen peroxide amperometric sensor based on planar carbon electrodes (PCE), modifie with gold particles and composite film silica-carbon nanomaterials has been developed. The combination of gold particles and composite film SiO 2-multi-wall carbon nanotubes (MWCNTs) as a PCE modifiers allows to detect H 2 O 2 by its oxidation current in the concentration range of 10-5-10-3 M with the detection limit of 7.0•10-6 M, which is one order lower than for PCE. A tenfold excess of ascorbic acid and other strong reductants interfere H 2 O 2 determination. Using of PCE, modified with SiO 2-CFO film, where CFO-nanoparticles of carbon fluorooxide allows to detect hydrogen peroxide by its reduction current, that significantly improves a selectivity. The highest sensitivity and linear range of calibration graph for H 2 O 2 determination were obtained for PCE-SiO 2-CFO.