A Study on the Suitability of Carbon Disk Microelectrodes for Trace Analysis of Lead and Copper by ASV

Abstract

The performance of carbon microdisk electrodes for the simultaneous trace analysis of lead and copper by anodic stripping voltammetry is investigated. The evaluation of the two metal ions in a single step, i.e., by employing a plating potential at which both cations are reduced simultaneously, gives unpredictable results due to the interaction between lead and copper deposited onto the electrode surface. In particular, the calibration plots of lead are not linear, while the copper stripping peak is quite broad and irreproducible. A two-steps deposition procedure, based on a preelectrolysis of copper performed at a potential at which lead ion is not reduced, followed by a simultaneous reduction of the two cations at large enough negative potentials, provides, instead, linear calibration graphs for lead. Copper can be determined without interference by plating the metal at a negative potential where lead ion is not reduced. The reliability of the two-steps procedure for the determination of lead and copper is verified in rain and wine samples.

Microelectrodes for the Determination of Heavy Metal Traces in Physiological Conditions. Hg, Cu and Zn Ions in Synthetic Saliva

“…In particular, the use of Saliva 2 leads to an anodic shift of more than 160 mV with respect to Saliva 3. Literature works [42,43,77,78] suggest the formation of Cu ions as intermediates in the oxidation of metal Cu; these ions are complexed by chloride ions to give CuCl À 2 , hence involving the consumption of only 1 mol of electrons per mol of oxidized Cu; in terms of potential values, our data result in good agreement with those reported in the cited references under analogous experimental conditions. Hence, as suggested by the value of 60 mV for the half-peak width, a one-electron oxidation process can be proposed also in our case, Cl À and SCN À acting as complexing agents for Cu ions in Saliva 2 and 3, respectively.…”

Simultaneous Electrochemical Detection and Determination of Lead and Copper at Boron-Doped Diamond Film Electrodes

“…However, some multicomponent systems can lead to interferences when metals have similar atomic radii and the same crystal structure, so that non linear results appear in standard addition measurements [5,17,18]. The formation of intermetallic compounds or solid solutions concerns, in general, diminished accuracy and precision, and most work has been directed at finding ways obviating its effects.…”

Modified carbon-containing electrodes in stripping voltammetry of metals. Part II. Composite and microelectrodes

“…The lower detection limit of determinable concentrations on electrodes made of a single unmodified carbon or graphite fiber is 10 −7 -10 −9 M [202 -212]. Still lower detection limits of 10 −8 -10 −10 M were achieved with For abbreviations aside from those defined here, see Tables 1 to 3 GF graphite fiber, CF carbon fiber, GCF glassy-carbon fiber, CFA carbon fiber array, CMEA carbon microelectrode array, CNTA carbon nanotubes array mercury-, gold-, and bismuth-modified ME, MEA and CNTA [213][214][215][216][217][218][219][220][221][222][223][224][225][226][227]; see Table 4.…”