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.

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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.

     

Simultaneous determination of lead,copper and zinc in multimetal ores and their processed products by activation analysis

A method is proposed for the simultaneous determination of lead, copper and zinc in multimetal ores and their products by cyclic irradiation and measurement. The relative standard deviation is 10–20%, the total time required for the analysis of one sample is 10 min.     

The determination of cadmium,copper, iron,lead and zinc in aerosols by atomic-absorption spectrometry

The determination of five elements in filter papers loaded with air particulate matter has been investigated. After a wet destruction of about 10 cm² of filter material by a standard procedure, analysis was carried out with a flame atomic absorption method for zinc and a flameless procedure for Cd, Cu, Fe and Pb. Furnace program parameters for each of the elements in different acid solutions are reported. The interferences of some common anions and the most abundant cations in aerosol material are described. For some urban and industrial samples, the results are compared with those obtained by energy-dispersive x-ray fluorescence. Accuracy was checked against standard samples.     

Radiochemical proton activation analysis for the determination of cadmium and lead in sediment reference materials

Proton activation analysis was used for the determination of cadmium and lead in three sediment reference materials. The method is based on the^111,112Cd(p, xn)¹¹¹ In and the^206,207,208Pb(p, xn)²⁰⁶Bi reactions.¹¹¹In and²⁰⁶Bi were chemically separated by anion exchange. The results obtained were taken into account for the certification of the materials and are in the excellent agreement with the certified values.     

Simultaneous determination of lead,copper, cadmium and zinc in pure zirconium metal by differential-pulse anodic stripping voltammetry

Zirconium metal (ca. I g) was dissolved in hydrofluoric acid, excess of which was removed by fuming with sulphuric acid. An aliquot of this solution was treated with sodium citrate and adjusted to pH 4.5. Lead, copper and cadmium were deposited on the hanging mercury drop electrode by applying a potential of ?0.8 V vs. Ag/AgCl for 1 min and anodic stripping voltammograms were recorded; the anodic peaks appeared at ?0.51, ?0.14 and ?0.67 V, respectively. In a separate run, zinc was deposited at ?1.2 V and the stripping peak appeared at ?1.1 V. Standard additions were used to quantify these impurities at levels in the low mg kg^?1 range, with relative standard deviations of 5–11%.     

Simultaneous spectrophotometric determination of cadmium, copper and zinc

A method for the simultaneous spectrophotometric determination of cadmium, copper and zinc based on the formation of their complexes with 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide is proposed. The absorption curves of these complexes overlap severely in the scanning range 380–480 nm. The analyte concentrations are calculated by a least squares fit of the pure spectra to the mixture spectra. A linear determination range of 0.1–1.7 μg/ml for cadmium, 0.1–1.3 μg/ml for copper and 0.2–1.2 μg/ml for zinc were obtained. The effect of interference was studied. The method has been applied to the determination of these metal ions in various type of materials.     

Simultaneous estimation of copper, zinc, cadmium and mercury in biological material by neutron activation analysis

Simultaneous determination of copper, zinc, cadmium and mercury with high sensitivity is possible by neutron activation analysis. After irradiation, the samples are digested and an initial separation of the four elements made by means of an ion-exchange resin. The elements in the separated fractions are then treated to give radio-chemical purity, precipitated, and their activities measured. A purely instrumental technique for the analysis of zinc in samples of biological material is also described. The samples are irradiated for a week and after the activity has decayed for about three months it is measured on a gamma-spectrometer.     

The determination of lead in environmental and geological materials by proton activation analysis

Lead is determined in environmental samples and in rocks using the^206,207,208Pb(p,xn)²⁰⁶Bi reaction. Bismuth is separated by anion exchange or by extraction with antimony diethyldithiocarbamate. Sources of errors such as volatilization of the matrix due to heating during the irradiation, variations of the abundance of the lead isotopes and the standardization were studied in detail. For concentrations between 11 mg/g and 3.7 g/g the relative standard deviation ranges from 2.6 to 5.4%. The detection limit is 10 ng/g.     

催化动力学光度法同时测定痕量铅和镉

在十六烷基三甲基溴化铵（CTAB）存在下，痕量的Pb(Ⅱ）和Cd(Ⅱ）在硼酸－氯化钾－氢氧化钠缓冲体系中，能同时催化过硫酸铵氧化焦锫酚红（PR）而发生褪色指示反应，通过研究该反应的最佳反应条件以及将多元线性回归（MIR）用于数据处理，建立了同时测定铅和镉的新方法，方法已用于废水及铜混中铅和镉的同时测定。     

Enzymatic determination of cadmium,zinc, and lead in plant materials

Prospects are outlined for using the following enzymes (native and immobilized on polyurethane foam) in the rapid and highly sensitive determination of cadmium, zinc, and lead ions in plant materials (wild grass, fresh pea, and grape): horseradish peroxidase and alkaline phosphatases isolated from chicken intestine and Greenland seal small intestine. The analytical ranges of the above metals are 1 × 10^–3?25, 7 × 10^?3?250, and 3 × 10^?2?67 mg/kg dry matter, respectively. The enzymatic determination procedures developed are based on the inhibiting effect of metal ions on the catalytic activity of peroxidase in the oxidation of o-dianisidine with hydrogen peroxide and alkaline phosphatases in the hydrolysis of p-nitrophenyl phosphate. The rates of enzymatic reactions were monitored spectrophotometrically or visually. In the analysis of plant extracts, their high acidity was diminished by choosing optimum dilution factors and pH values for test samples and the nature and concentration of a buffer solution. The interference of iron(III) was removed by introducing a 0.1 M tartaric acid solution into the indicator reaction. The accuracy of the results of the enzymatic determination of cadmium, zinc, and lead in plant materials was supported by atomic absorption spectrometry and anodic stripping voltammetry.     

Simultaneous determination of cadmium and lead in urine by means of computerized potentiometric stripping analysis

In computerized potentiometric stripping analysis for cadmium and lead in urine the samples are acidified with hydrochloric acid to a total concentration equal to 0.5 M. The sample is pre-electrolyzed at —1.25 V vs. SCE for 2 min without prior sample heating or deoxygenation, the working electrode being a mercury pre-coated glassy-carbon electrode. The lead and cadmium concentrations are evaluated by means of standard addition. Detection limits are 1 nM for both elements. Results obtained by potentiometric stripping analysis and by solvent extraction/atomic absorption are compared for samples from unexposed persons and from one patient under penicillamine treatment. The relative merits of the potentiometric stripping, anodic stripping and atomic absorption techniques are discussed.     

两种全光谱技术同时测定铜、镉、锌

建立了一种小波软阈值法（STWPLS）同时测定铜（Ⅱ）、镉（Ⅱ）、锌（Ⅱ）方法。此法结合多分辩分析和软阈值法改进除噪质量。通过最佳化，小波函数，低频收缩截止水平（L）和阈值法类型分别选为Daubechies8,3和HYBRID。并将此法与偏最小二乘法（PLS）做了比较。     

Simultaneous determination of copper,manganese, zinc and sodium in plant materials by neutron activation analysis

Neutron activation analysis has been used for the simultaneous determination of Cu, Mn, Zn and Na in plant materials. The heterocyclic dye PAN has been applied as a chelating agent to achieve the group chemical separation of Mn, Cu, Ni and Zn. Various factors which affect the formation and extraction of the PAN-metal chelates have been studied and optimized, using suitable aqueous solutions to selectively strip these elements from the organic phase. This procedure has been applied to the determination of these elements in ‘Bowen’s Kale’ and U.S. NBS Citrus-leaves and Tomatoleaves samples.     

Direct stripping voltammetric determination of lead,cadmium and zinc dithizonates

A procedure is described in order to determine lead, cadmium and zinc dithizonates by stripping voltammetry. The polarographic analysis is performed in a medium of methanol and benzene (chloroform) in a ratio of 7:1 and in the presence of silver dithizonate. Sodium nitrate was used as a base electrolyte. By carrying out these analytic conditions it is possible to perform directly the stripping voltammetric analysis in benzene (chloroform) solution of extracted dithizonates, without further treatment. Silver nitrate in methanol is added to dithizonates in order to free lead, cadmium, and zinc from their complexes, to be determined polarographically.     

Determination of thallium in zinc by proton activation analysis

The determination of thallium in unalloyed zinc by proton activation analysis, based on the ²⁰³Tl (p,3n)²⁰¹Pb reaction, is described. Lead-201 was radiochemically separated from the matrix activities (gallium, copper and zinc) by cation exchange, anodic deposition of lead (IV) oxide and precipitation as lead thionalide. Thallium (III) oxide was used as the standard. The method was applied to the BCR reference materials 321,322,323,324 and 325 Unalloyed Zinc. The detection limit is 17 ng g^?1. The relative standard deviation obtainable is 5-1% in the 1-40 μg g^?1 concentration range.     

Determination of copper in zinc by proton activation analysis

A method for the determination of copper in zinc by proton activation analysis using the⁶³Cu(p, n)⁶³Zn reaction has been developed.⁶³Zn has to be separated chemically from gallium and copper activities formed out of the zinc matrix and from indium activity formed out of cadnium impurity. Gallium radionuclides are retained on a cation exchanger in chloride medium and the residual activity is extracted in di-isopropyl ether. Copper and indium are subsequently extracted with cupferron in chloroform. The method was applied to BCR reference materials with a copper concentration at the μg.g^?1 level. The detection limit amounts to 0.5 μg.g^?1.     

Simultaneous determination of cadmium and lead in wine by electrothermal atomic absorption spectrometry

A method has been developed for the direct simultaneous determination of Cd and Pb in white and red wine by electrothermal atomic absorption spectrometry (ET-AAS) using a transversely heated graphite tube atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of both analytes during pyrolysis and atomization stages were investigated in 0.028 mol l⁻¹ HNO₃ and in 1+1 v/v diluted wine using mixtures of Pd(NO₃)₂+Mg(NO₃)₂ and NH₄H₂PO₄+Mg(NO₃)₂ as chemical modifiers. With 5 μg Pd+3 μg Mg as the modifiers and a two-step pyrolysis (10 s at 400°C and 10 s at 600°C), the formation of carbonaceous residues inside the atomizer was avoided. For 20 μl of sample (wine+0.056 mol l⁻¹ HNO₃, 1+1, v/v) dispensed into the graphite tube, analytical curves in the 0.10–1.0 μg l⁻¹ Cd and 5.0–50 μg l⁻¹ Pb ranges were established. The characteristic mass was approximately 0.6 pg for Cd and 33 pg for Pb, and the lifetime of the tube was approximately 400 firings. The limits of detection (LOD) based on integrated absorbance (0.03 μg l⁻¹ for Cd, 0.8 μg l⁻¹ for Pb) exceeded the requirements of Brazilian Food Regulations (decree #55871 from Health Department), which establish the maximum permissible level for Cd at 200 μg l⁻¹ and for Pb at 500 μg l⁻¹. The relative standard deviations (n=12) were typically <8% for Cd and <6% for Pb. The recoveries of Cd and Pb added to wine samples varied from 88 to 107% and 93 to 103%, respectively. The accuracy of the direct determination of Cd and Pb was checked for 10 table wines by comparing the results with those obtained for digested wine using single-element ET-AAS, which were in agreement at the 95% confidence level.     

Computerized potentiometric stripping analysis for the determination of cadmium,lead, copper and zinc in biological materials

Two different types of tinned mussels and a bovine liver reference sample have been analyzed for Zn, Cd, Pb and Cu by means of computerized potentiometric stripping analysis and atomic absorption spectrometry. The samples were digested by two different procedures, one employing nitric acid only and the other employing nitric and perchloric acids. It is shown that computerized stripping analysis can be used in samples containing high concentrations of electroactive organic nitro compounds, without sample deoxygenation.     

Simultaneous determination of silicon and phosphorus in cast iron by 14 MeV neutron activation analysis

A fast (10 min), non-destructive simultaneous determination of silicon and phosphorus in cast iron and steel by 14 MeV neutron activation was developed. The 1.78 MeV²⁸Al activity (T=2.24 min) induced by the reaction²⁸Si(n, p)²⁸Al is counted on a NaI(Tl) detector. Two measurements are made to correct for the 1.81 MeV⁵⁶Mn activity (T=2.58 hr) from the iron matrix. However,²⁸Al is also produced via³¹P(n, α)²⁸Al. By (n, 2n) reaction, phosphorus yields also³⁰P (T=2.6 min), the 0.511 MeV annihilation radiation of which is counted by two opposite NaI(Tl) detectors in coincidence. Again, two successive coincidence measurements are carried out in order to take into account the⁵³Fe activity (β⁺; T=8.9 min) from⁵⁴Fe(n, 2n)⁵³Fe. The²⁸Al measurement is appropriately corrected via the computed phosphorus content. An oxygen flux monitor was used to normalize to the same flux. Nuclear interferences have been examined. Special attention has been paid to the presence of copper. The standard deviation for phosphorus being as high as ca. 0.09% P for a single determination, this technique can only be practical as an independent phosphorus analysis for high phosphorus cast irons. The precision on the²⁸Al measurement is 5% relative for 0.2% Si and 2.5% above 1% Si. Aspirant of the N.F.W.O.     

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.