The determination of copper,lead, cadmium and zinc in human teeth by anodic stripping voltammetry

Differential pulse anodic stripping voltamrnetry and a hanging mercury drop electrode are used for the determination of copper, lead, cadmium and zinc in Norwegian teeth and pure hydroxyapatite. Special attention is given to the choice of decomposition procedure and the determination of the blank values. A complete dissolution of the tooth material and satisfactory blank values can be obtained by using decomposition with nitric acid in a Teflon bomb.     

Microwave Assisted Digestion Method for the Determination of Cadmium,Copper, Lead,and Zinc in Biological Materials

Anodic stripping voltammetry is useful instrumental method for trace element determination in biological materials. It is however extremely demanding to the quality of the sample preparation process. The high‐pressure microwave assisted digestion seems to meet its requirements. The differential pulse anodic stripping voltammetry technique was used for determination of cadmium, copper, lead and zinc in certified reference materials both of plant and of animal origin to prove the analytical properties of such sample preparation method. The found concentrations have been in satisfactory agreement with the certified values. The elaborated digestion procedure is greatly universal and has required accuracy and precision.     

Determination of mobile form contents of Zn, Cd, Pb and Cu in soil extracts by combined stripping voltammetry

The amount of mobile forms of Zn, Pb, Cd and Cu in extracts obtained by treating soil samples with ammonium nitrate were determined by an appropriate combination of anodic and cathodic stripping voltammetry with hanging mercury drop electrode. Every analysis required three mercury drops: on the first one, zinc was determined; on the second, cadmium and lead; on the third, copper was determined. Zinc, lead and cadmium were determined by conventional differential-pulse anodic stripping voltammetry. For copper determination, adsorptive differential-pulse cathodic stripping voltammetry with amalgamation using chloride ions as a complexing agent was applied. The standard deviation of the results was from 1 to 10% depending on the metal content in the sample. Voltammetric results were in good agreement with the AAS analysis. No microwave digestion of soil extracts was necessary.     

Simultaneous determination of lead, cadmium and zinc in aerosols by anodic stripping voltammetry

Summary The simultaneous determination of lead, cadmium and zinc in air particulate matter by anodic stripping voltammetry is described. Optimum conditions for the anodic stripping of lead, cadmium and zinc were determined using ammonium tartrate buffer at pH 4.5. Interferences from other metals were not encountered and the estimations were reproducible within a standard deviation of ±10%. Low blank values and high sensitivity of the method allowed the determinations at sub-ppb levels with an electrolysis time of 3–10 min. The geometric mean concentrations of lead, cadmium and zinc at various locations in Greater Bombay during 1979 are also presented.

---

Simultanbestimmung von Blei, Cadmium und Zink in Aerosolen durch anodische Stripping-Voltammetrie

Zusammenfassung Die optimalen Bedingungen für die Bestimmung von Pb, Cd und Zn unter Verwendung von Ammoniumtartratpuffer pH 4,5 wurden ausgearbeitet. Störungen durch andere Metalle traten bei den untersuchten Aerosolen nicht auf. Die Standardabweichungen lagen bei ±10%. Infolge niedriger Blindwerte und hoher Empfindlichkeit konnten Bestimmungen im sub-ppb-Bereich mit Elektrolysenzeiten von 3–10 min durchgeführt werden. Ein Überblick über die Konzentration der genannten Metalle in der Luft von Bombay wird gegeben.

     

Analyse de la fraction labile du zinc,cadmium, plomb et du cuivre dissous en milieu marin côtier par la redissolution anodique à impulsions différentielles

Analysis of the labile fraction of zinc, cadmium, lead and copper dissolved in the coastal marine environment using differential pulse anodic stripping voltammetry. The determination of the optimal experimental conditions for the dosage of labile concentrations of heavy metals such as cadmium, copper lead and zinc, in a coastal marine environment has been performed. The method used was differential pulse anodic stripping voltammetry (DPASV) with hanging mercury drop. To cite this article: M. El Makhfouk et al., C. R. Chimie 6 (2003).     

Pulsed anodic stripping voltammetry of zinc,cadmium and lead with a mercury-coated wax-impregnated graphite electrode

The use of a thin mercury-film wax-impregnated graphite electrode for the simultaneous determination of cadmium, lead and zinc in an acetate buffer by differential pulse anodic stripping voltammetry is described. Optimal instrumental parameters for maximum resolution and sensitivity for simultaneous analysis of these three elements in natural waters are discussed. The interference of copper with the determination of zinc is investigated in detail. An optimal mercury film thickness for this electrode is suggested.     

Particle Size Determination of Trace Elements in Urban Air

Abstract

Airborne urban particulate matter was collected and fractionated according to size by cascade impactors. The elements zinc, cadmium, copper and lead on each size fraction were analyzed by anodic stripping voltammetry. The elements aluminum, iron, manganese, calcium and magnesium were analyzed by atomic absorption spectrophotometry. The data showed three different classes of particle size distribution for these nine elements. Lead and cadmium belonged to the first class with more than 70 % of the total collected element associated with particles having aerodynamic diameters below 0.5 micron. The calculated average mass median equivalent diameter (MMD) of cadmium and lead was approx. 0.1 micron. In the second class about 60% of the elements Zn, Cu, Mg and Fe was associated with particles smaller than 0.5 micron. The average MMD's for these elements were between 0.3 and 0.4 micron. For the elements Al, Ca and Mn about 50% of the metal was associated with particles smaller than 0.5 micron and the MMD's were between 0.5 and 0.6 micron. Examination of elemental ratios (using Al as a reference element) showed that Pb and Cd were about 1000 times more concentrated in atmospheric particulate matter than in average crustal material and that in general the Pb/Al and Cd/Al ratios are inversely proportional to particle size. The Zn/Al and Cu/Al ratios of atmospheric partides were age or less independent of particle size and approx. 20 times higher than these same ratios in average crustal material. The ratios Fe/Al, Mn/AI, Ca/M and Mg/AI in all sizes of particulate matter were essentially identical to the same ratios in average crustal material.     

The determination of bromide,chloride and lead in airborne particulate matter by stripping voltammetry

Cathodic and anodic stripping voltammetry are proposed for the simultaneous determination of chloride, bromide and lead in atmospheric particulate matter. Particulate matter collected on Nucleopore membrane filters with high-volume pumps is digested in a dilute nitric acid wash at elevated temperature and pressure for 1 h. The sample is then removed to the electrochemical cell and analyzed directly for chloride and bromide by cathodic stripping and for lead by anodic stripping. The total amount of halide is first determined and then, by changing the deposition potential, the amount of bromide only is determined. The chloride is found indirectly by difference. Analysis time for the three elements is approximately 20 min beginning with a prepared sample.     

Copper Complexation with Soluble and Surface Freshwaters Ligands

Speciation of copper has been done using samples collected at different times of the year (December 92 and October 93) and in three sites of a polluted river (Este River, Northern Portugal). Filtered samples and the suspended particulate matter were titrated with metal ion and the labile metal concentrations measured by anodic stripping voltammetry (DPASV). An extra peak in the Cu voltammograms has been noticed when titrating filtered samples and its origin was investigated. Results have suggested that the extra peak is due to copper(I) stabilized by ligands adsorbed on the mercury electrode and a model for the electrochemical mechanism is proposed. From titrations of the same samples with zinc, cadmium and lead it has been concluded that there are two types of organics in the river water: macromolecules and small molecules with D_ML≈D_M with higher affinity for soft cations such as Cd(II) and Cu(I), that can be adsorbed on mercury electrode as anions.     

Computerized electroanalysis : Multiple scanning anodic stripping and its application to sea water

the determination of copper, lead, zinc, cadmium and bismuth in standard sea water samples by multiple scanning anodic stripping has been investigated. The influence of plating potential and sample pH has been studied.     

Determination of antimony in impure zinc sulphate solution by coprecipitation followed by differential pulse anodic stripping voltammetry

A simple coprecipitation technique for the quantitative separation of the antimony present in impure zinc sulphate electrolyte followed by its voltammetric determination is described. Antimony in microgram levels is separated from the matrix zinc sulphate solution, which contains higher levels of copper, lead and cadmium, and is subsequently determined by differential pulse anodic stripping voltammetry (DPASV) in 3 M hydrochloric acid. Hydrous manganese dioxide is employed as the collector. This procedure, which effects considerable saving in time, is of comparable accuracy to the conventional spectrophotometric method using the antimony-rhodamine B complex. A series of synthetic zinc sulphate solutions spiked with known amounts of antimony as well as plant solutions gave near theoretical values.     

Determination of heavy metals in real samples by anodic stripping voltammetry with mercury microelectrodes : Part 1. Application to Wine

Differential-pulse anodic stripping voltammetry with a mercury microelectrode is used for the determination of zinc, cadmium, lead and copper in wine at its natural pH without pretreatment. The effects of the matrix on the stripping peaks are studied in detail by varying the concentration of the metals. Intermetallic (CuZn) interferences and the effects of oxygen are described. The results obtained for the labile metal contents varied from 2 μg l^?1 for cadmium to 148 μg l^?1 for zinc; standard addition plots were linear over about two orders of magnitude above these levels, demonstrating the negligible effect of organic matter. Acidification of the sample with hydrochloric acid to pH 1 allowed the total metal contents to be determined. The reliability of the method was tested by comparison with the results obtained with atomic absorption spectrometry; the differences were within 10–20%.     

Determination of trace metals in rain water by differential-pulse stripping voltammetry

Differential-pulse stripping voltammetry is applied to measure zinc, cadmium, lead and copper by anodic stripping and selenium(IV) by cathodic stripping in rain water at pH 2; subsequently, at pH 9,1, manganese is measured by anodic stripping on the same portion, and cobalt and nickel are measured in the adsorptive mode after formation of their dimethylglyoximates. The instrumental parameters are optimized. The linear ranges, mutual interferences and detection limits are studied. Excellent accuracy is demonstrated; the standard deviation is around 15% at 2.5–50 μg l^?1 levels. The method is shown to be applicable for rain water.     

Simultaneous Determination of Cadmium,Copper, Lead and Zinc in Amino Acid Parenteral Nutrition Solutions by Anodic Stripping Voltammetry and Sample Digestion by UV Irradiation

Abstract

Irradiation with ultraviolet (UV) energy was investigated to assay cadmium, copper, lead, and zinc by anodic stripping voltammetry (ASV) in amino acid parenteral nutrition (PN) solutions. Sample digestion by UV irradiation showed the best performances to liberate the metals from the samples (metal recoveries between 90% and 102%) in comparison with classical oxidative wet digestion methods. The best UV digestion condition was obtained with 1:10 diluted PN samples irradiated during 10 h at 90±3°C with the addition of one aliquot of 50 µL concentrated H₂SO₄ and repeated additions of 50 µL 30% (v/v) H₂O₂ at each 60 min irradiation interval. By using the UV digestion procedure cadmium, copper, lead, and zinc were simultaneously assayed in commercial amino acid PN solutions by ASV. The metal concentrations ranged between 1.3 to 4.4 for cadmium, 2.9 to 40.8 for copper, 4.4 to 16.8 for lead, and 1.4 to 208.5 for zinc. The ASV method correlated well with atomic absorption spectrometry measurements to assay the investigated analytes in amino acid PN samples after the UV digestion.     

Analysis of rain water by differential-pulse stripping voltammetry in nitric acid medium

Differential-pulse anodic stripping voltammetry is applied to determine cadmium, lead and copper in rain water acidified with nitric acid to pH 1.5, and zinc after partial neutralization to pH 4.5. Subsequently, cobalt and nickel are measured in the adsorptive mode after formation of their dimethylglyoximates. The effects of pH on the stripping peaks for Zn, Cd, Pb and Cu and of chloride on the stripping peak of copper are reported. Good agreement is found with d.p.s.v. determinations in hydrochloric acid medium and with a.a.s. measurements in most cases. Excellent accuracy is demonstrated; the average relative standard deviation per measurement appears to be between 12 and 22% for the overall analytical procedure for concentrations of 0.15–50 μgl^?1 of the various metals in the samples.     

Determination of the Speciation of Cadmium, Lead, and Copper in Seawater and the Complexing Ability of Seawater Components with Respect to Cd, Pb, and Cu

The concentrations of cadmium, lead, and copper in the water of Amur Bay were determined by anodic stripping voltammetry, and the speciation of these elements in the seawater was calculated. The predominant complexes of cadmium, lead, and copper were determined in the seawater by ion exchange under dynamic conditions. The concentrations of anionic, cationic, and neutral complexes of cadmium, lead, and copper in the seawater were calculated. The ability of seawater components to form complexes with these trace elements was assessed.     

利用碘离子增感效应和金电极导数阳极溶出法研究铜丶铅和镉的同时测定

A method of simultaneous determination of copper (II), lead (II) and cadmium (II) in sulphuric acid-iocide ion medium was established by derivative anodic stripping voltammetry (DASV) on the gold electrode. The peak theights of lead and cadmium were increased by enhancement effect of iodide ion and the peaks of bismuth and copper were well formed and completely resolved on gold electrode in the presence of iodide ion, therefore peak of copper is not affected by bismuth. The sensitivities for copper, lead and cadmium were very high and their peak potentials in the stripping voltammogram were +0.25, -0.2 and -0.27 volt, respectively. The dependence of peak height of these elemets on their concentrations was linear. The detection limits for copper, lead and cadmium were 0.2 0.2 and 0.05 ppb, respectively. We have further studied the electrode process by means of triangle cyclic voltammetry and proved that he electrode reaction of copper is reversible, and that the reversibility of electrode reactions of lead and cadmium is not good.     

The determination of cadmium,lead and copper in urine by differential pulse anodic stripping voltammetry

Differential pulse anodic stripping voltammetry is used for the simultaneous determination of cadmium, lead and copper in different types of urine samples. Unlike most biological samples, urine can be analyzed directly for cadmium and lead without pretreatment of the sample; a significant increase in sensitivity is obtained if the analysis is carried out at an elevated temperature. The complete decomposition of urine with a mixture of nitric, perchloric and sulphuric acids is also described; this procedure makes it possible to determine copper simultaneously. Good agreement was obtained between the two procedures, and the recovery of metals from spiked samples was satisfactory for both methods. The relative merits of the two approaches are discussed.     

Anodic stripping voltammetry at a mercury film electrode: baseline concentrations of cadmium,lead, and copper in selected natural waters

A simple, rapid, and inexpensive anodic stripping voltammetric method with a mercury thin film electrode is reported for the establishment of baseline concentrations of cadmium, lead, and copper in natural waters. The procedure for routine surface preparation of wax-impregnated graphite mercury film electrodes requires about 30 min. Concentrations in the 0.006–6 μg l^-1 range are determined by linear d.c. voltage sweeps; the total time for a plating and stripping cycle is 6 min or less. The need for pressure-digesting samples for copper determinations is demonstrated. The a.s.v. results correlate well with corresponding analyses performed by graphite-furnace atomic absorption spectrometry.     

Anodic stripping voltammetry with medium exchange in trace element speciation

The application of medium exchange in anodic stripping voltammetry (ASV) was investigated by determing the fractions of ASV-labile copper, lead, cadmium and zinc in the presence of a variety of natural and sysnthetic ligands in a soft water. Pristin and polluted samples of river water were also tested. Medium exchange, where the test solution is replaced after electrodeposition by a simple electrolyte such as acetate buffer, before the oxidation (stripping) of the deposited metals, can ensure that the ASV-labile metal fraction depends only on the parameters of the electrodeposition step. Significant differences were found for ASV-labile fractons when medium exchange was used for the two river water samples, and for several mertal/ligand combinations such as copper/chloride, copper/humic acid, and zinc/tannic aid. It is recommended that medium exchange be used routinely for ASV-labile determinations.