Determination of cadmium,indium and zinc in nickel—base alloys by atomic absorption spectrometry with introduction of solid samples into furnaces

Atomic absorption spectrometry with an induction furnace is used for the determination of cadmium (0.002–2 μg g^-1), indium (0.6–350 μg g^-1) and zinc (0.05–26 μg g^-1) in 0.8–35 mg samples of nickel—base alloys dropped into the furnace. A resistively-heated furnace is employed for the determination of lower concentrations of indium (<0.6 μg g^-1). Standardised alloys were used for calibration. Accuracy, precision and detection limits are described for numerous nickel—base alloys. With alloys containing zinc, > 0.1 μg Cd g^-1 and >0.6 &,mu;g In g^-1, the relative standard deviations are 12%, 8% and 7%, respectively. Calculated detection limits for cadmium, indium and zinc are 2 ng g^-1, 10 ng g^-1 and 10 ng g^-1, respectively.     

The determination of traces of antimony,tin and arsenic in cadmium by pulse polarography

Traces of antimony, tin and arsenic in cadmium products were determined by pulse polarography. Arsenic was distilled, while antimony and tin were precipitated as hydroxides with manganese dioxide as carrier; some lead was coprecipitated with tin, hence these elements were further separated by distillation. In all cases quantitative recoveries were obtained. Antimony(III) was determined in a hydrochloric acid-sodium hypophosphite mixture, tin(IV) in a hydrochloric-hydrobromic acid mixture and arsenic(III) in sulphuric acid as supporting electrolytes; for arsenic(III), methylene blue had to be added. A sample weight of 10 g and an end volume of 10 ml allowed the determination down to about 0.004 p.p.m. antimony, 0.006 p.p.m. tin and 0.003 p.p.m. arsenic in cadmium. Several synthetic samples and commercially available cadmium products were analysed.     

Spectrophotometric determination of zinc, cadmium, and lead after extraction of their morpholine-4-carbodithioates into molten naphthalene and replacement by copper

Zinc, cadmium, and lead react quantitatively in the pH ranges of 3.9–9.2, 3.5–11.2, and 5.5–10.5, respectively, to form water insoluble and thermally stable complexes which are easily extracted into molten naphthalene. The solid naphthalene containing the colorless complex is dissolved in chloroform and then replaced by copper to develop a yellow color in the chloroform layer. The absorbance in each case is measured at 435 nm against reagent blank. Beer's law holds over the concentration ranges of 3.5–95.0, 3.0–105.0, and 8.5–125. 0 μg for zinc, cadmium, and lead, respectively, into 10 ml of the chloroform solution. The molar absorptivities are calculated to be Zn, 1.048 × 10⁴ liters mol⁻¹ cm⁻¹; Cd, 1.054 × 10⁴ liters mol⁻¹ cm⁻¹, and Pb, 1.014 × 10⁴ liters mol⁻¹ cm⁻¹ with sensitivities in terms of Sandell's definition of 0.0062 μg Zn/cm², 0.010 μg Cd/cm², and 0.020 μg Pb/cm², respectively. Ten replicate determinations of sample solutions containing 30 μg of zinc, 18.7 μg of cadmium, and 42.5 μg of lead give mean absorbances 0.480, 0.175, and 0.208 with standard deviations of 0.0017, 0.0013, and 0.0015 or relative standard deviations of 0.35, 0.74, and 0.72%, respectively. The interference of various ions has been studied and the method has been applied to the determination of cadmium in various synthetic mixtures and zinc and lead in some standard reference materials.     

Determination of cadmium,copper and lead in mineral coal using solid sampling graphite furnace atomic absorption spectrometry

Solid sampling graphite furnace atomic absorption spectrometry (SS-GF AAS) was investigated as a potential technique for the routine determination of trace elements in mineral coal and cadmium, copper and lead were chosen as the model elements. Cadmium and lead could be determined at their main resonance lines at 228.8 nm and 283.3 nm, respectively, but an alternate, less sensitive line had to be used for the determination of copper because of the high copper content in coal. No modifier was necessary for the determination of copper and calibration against aqueous standards provided sufficient accuracy of the results. For the determination of cadmium and lead two different modifiers were investigated, palladium and magnesium nitrates in solution, added on top of each sample aliquot before introduction into the atomizer tube, and ruthenium as a ‘permanent’ modifier. Both approaches gave comparable results, and it is believed that this is the first report about the successful use of a permanent chemical modifier in SS-GF AAS. Calibration against solid standards had to be used for the determination of cadmium and lead in order to obtain accurate values. The agreement between the values found by the proposed procedure and the certificate values for a number of coal reference materials was more than acceptable for routine purposes. The detection limits calculated for 1 mg of coal sample using the ‘zero mass response’ were 0.003 and 0.007 μg g⁻¹ for cadmium with the permanent modifier and the modifier solution, respectively, approximately 0.04 μg g⁻¹ for lead, and 0.014 μg g⁻¹ for copper.     

Capabilities of femtosecond laser ablation ICP-MS for the major, minor, and trace element analysis of high alloyed steels and super alloys

Femtosecond laser ablation inductively coupled plasma mass spectrometry was used for the quantification of 23 metallurgical relevant elements in unalloyed, alloyed and highly alloyed steels, and super alloys. It was shown that by using scanning mode ablation with large ablation spot diameters (250 μm), stable and representative sampling can be achieved for the majority of elements, except for bismuth and lead. For Bi and Pb up to 46%, temporal relative standard deviation (TRSD) was encountered, whereas for most other elements, the TRSDs were below 10%. Calibration with matrix-matched and non-matrix-matched standards provided similar agreement within the uncertainty of the certified values. However, the non-matrix-matched standard-based quantification was more influenced by interferences rather than ablation- or excitation-related matrix effects. The method was validated using 34 certified reference materials. ⁵²Cr, ⁵¹V, or ⁵⁵Mn were used as internal standards due to the fact that the Fe concentration was not certified for the majority of reference materials. The determined concentrations for major and minor elements indicate that the total matrix internal standardization (100 wt.%) is applicable, which requires no knowledge about the steel samples prior to analysis.     

Determination of Fluorine, Chlorine, and Bromine by Molecular Absorption Spectrometry

Fluorine was determined by molecular absorption spectrometry (MAS) in a graphite tube furnace, and fluorine, chlorine, and bromine were determined in a flame. For the fluorine work, aluminum nitrate was added as a reagent to produce aluminum fluoride molecules whose absorbance was monitored with emission from a platinum hollow cathode lamp (HCL) at 227.45 nm. A deuterium arc lamp was employed for background correction. For the furnace work, barium nitrate was used as a chemical modifier to increase the absorption signal. After optimization of the chemical and furnace conditions, a detection limit of 160 pg F was obtained, with a linear dynamic range of two orders of magnitude. Graphite furnace MAS was used to accurately determine fluoride in dental rinse and National Institute of Standards and Technology oyster tissue, but the precision was between 21 and 23%. Low recoveries were obtained for the determination of trifluoroacetic acid and l,2,2,3-tetrafluoropropan-1-ol by graphite furnace MAS. The detection limit for F by flame MAS was 13 mg liter⁻¹ which is a factor of 5 lower than the best reported flame MAS detection limit. Chlorine was determined by flame MAS with the aluminum chloride molecule. Excitation was done at 261.4 nm with a lead HCL. and a detection limit of 180mg liter⁻¹ was obtained. Flame MAS of bromine was done by use of AlBr (excitation at 279.0 nm with an arsenic HCL) and InBr (excitation at 284.3 nm with a chromium HCL), but very poor detection limits were obtained: 24.5 g liter⁻¹ and 500mg liter⁻¹, respectively.     

Optimization of operating conditions of axially and radially viewed plasmas for the determination of trace element concentrations from ultrasound-assisted digests of soil samples contaminated by lead pellets

The method of ultrasound-assisted extraction followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element concentrations (arsenic, copper, lead, antimony, and zinc) in shooting range areas was optimized. Optimization was achieved not only on the basis of the analysis of appropriate standard reference materials but also on that of 31 synthetic mixtures of matrix and analyte elements (aluminum, antimony, arsenic, calcium, copper, lead, iron, manganese, silicon, and zinc), in five concentrations. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg II 280.270 nm/Mg I 285.213 nm line intensity ratio. The highest Mg II 280.270 nm/Mg I 285.213 nm line intensity ratios were observed when a nebulizer gas flow of 0.8 L min⁻¹, auxiliary gas flow of 0.2 L min⁻¹ and plasma power of 1400 W were used for both the axially and radially viewed plasmas. The analysis of 31 synthetic mixtures of the selected elements showed that As concentrations could be accurately determined with axially viewed plasma alone. The determination of Pb and Sb could be performed with either axially or radially viewed plasma whereas, surprisingly, Cu could be determined with high accuracy using radial plasma alone with a power of 1400 W. All the elements investigated were determined with high accuracy using robust plasma conditions and a combination of axially and radially viewed plasmas. The total recoveries of elements from SRM 2710 (Montana soil) and SRM 2782 (Industrial sludge) were highly comparable to leach recoveries certified by the National Institute of Standards and Technology (NIST).     

Atomic absorption spectrometric determination of indium in gallium arsenide

Summary The determination of indium in heavily doped gallium arsenide (0.2–1.2 mg g^–1 In), by both electrothermal and flame AAS is reported. The sample is first decomposed with nitric acid and the diluted solution is atomized by employing the more convenient technique. The conventional air-acetylene flame is used for samples containing at least 1 mg g^–1 indium. For lower concentrations the electrothermal atomization is required and matrix-matched standards become necessary. Platform sampling is shown to improve both sensitivity and repeatability in comparison with the tube-well sampling. Dependence of the matrix effect on both the signal measurement mode and deterioration of the platform is examined. By increasing the sample mass up to 100 mg, without further dilution of the solution to be injected into the furnace but with the optical correction of the background, a detection limit (6 s) of 4.2 ng g^–1 (1.2×10¹⁴ atoms cm^–3) is achieved. The method was applied to In doped GaAs samples and the results are compared with those independently obtained by differential pulse polarography.

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AAS-Bestimmung von Indium in Galliumarsenid

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This work was presented at the Euroanalysis VI Conference (Paris, September 7–11, 1987)     

Atomic-absorption determination of gold in blister copper and speiss products

Summary The determination of gold at 10^–3–10^–4% levels in black copper and speiss is based upon selective dissolution of the samples with sulphuric acid and separation of the matrix elements by filtration. Gold is determined in the solid residue by flame atomic absorption spectrometry. Relative standard deviation was 7%–10% for about 20 g Au/t.

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AAS-Bestimmung von Gold in Rohkupfer und Speiseprodukten

     

X-ray fluorescence analysis of titanium alloys

An X-ray solution method is proposed for determining major amounts of Mo, Sn and Zr in Ti alloys. The method utilizes adjacent elements in the periodic table as internal standards and has been successfully applied to levels of 3-10% Sn, 11-40% Mo and 6-20% Zr. The procedure involves three steps: dissolving the sample with a suitable acid mixture; adding the suitable internal standard at the concentration levels experimentally found to give optimum accuracy and precision; analysing the resulting solution mixture by X-ray fluorescence. Antimony was found to be a suitable internal standard for its adjacent element tin at a concentration ratio of 3:1 Sb:Sn. Niobium was successfully used for both its adjacent elements, molybdenum and zirconium, at 2:1 concentration ratios, Nb:Mo and Nb:Zr. A number of elements non-adjacent to tin, molybdenum and zirconium (i.e., copper, bromine, titanium, bismuth and tantalum) were experimentally found unsuitable as internal standards. Concentration factors of the internal standard and the adjacent elements sought were found to affect significantly the precision of analysis.     

The measurement of high proton affinities for a variety of metallic compounds: a new approach by flame-ion mass spectrometry

A small amount (≤ 10⁻⁶ mol fraction) of four alkaline earth metals, tin and yttrium were introduced into five, premixed, fuel-rich, H₂–O₂–N₂ flames at atmospheric pressure in the temperature range 1820–2400 K. Aqueous salt solutions of the metals were sprayed into the premixed flame gas as an aerosol using an atomizer technique. Ions in a flame were observed by sampling flame gas through a nozzle into a mass spectrometer. The concentrations of the major neutral metallic species present in the flame were calculated from thermodynamic data currently available. The principal metallic ions observed were AOH⁺ (A = Mg, Ca, Sr, Ba, Sn) and A(OH)₂⁺ (A = Y), formed initially by proton transfer to AO and OAOH from H₃O⁺, a natural flame ion. Except for Mg, the ions were also produced by chemi-ionization processes. By adjusting the concentration(s) of the salt solution in the atomizer, it was found that a pair of ions could be brought into equilibrium within the time scale of the flame; the pairs included H₃O⁺ with a metal ion or two metallic ions. Because water is a major product of combustion, a very large difference in proton affinity PA⁰(AO) − PA⁰(H₂O) ≤ 490 kJ mol⁻¹ (117 kcal mol⁻¹) could be attempted for the proton transfer equilibrium. Using PA⁰(H₂O) = 691.0 kJ mol⁻¹ (165.2 kcal mol⁻¹) as a reference base to anchor the proton affinity scale, ion ratio measurements led to proton affinity PA⁰ values of 766, 912, 1004, 1184, 1201, and 1222 kJ mol⁻¹ (183, 218, 240, 283, 287, and 292 kcal mol⁻¹) corrected to 298 K for OYOH, SnO, MgO, CaO, SrO, and BaO, respectively; of these, only the value for OYOH has not been reported previously. If it is assumed that the neutral thermodynamic data are correct (although some appear to be in error), the uncertainties in the PA results reported here are ± 21 kJ mol⁻¹ (5 kcal mol⁻¹). The realization that these equilibria can be achieved in flames provides a new approach to consolidate and build the high end of the proton affinity ladder, primarily of metallic species which are not accessible at lower temperatures.     

Determination of copper, cadmium and lead in seawater and mineral water by flame atomic absorption spectrometry after coprecipitation with aluminum hydroxide

An aluminum hydroxide coprecipitation method for the determination of cadmium, copper and lead by flame atomic absorption spectrometry in aqueous solutions, seawater and mineral water samples has been investigated. The coprecipitation conditions, such as the effect of the pH, the amount of carrier element, the effect of possible matrix ions and the time were examined in detail for the studied elements. It was found that cadmium, copper and lead are co-precipitated quantitatively (≥95%) with aluminum hydroxide at pH 7 with low R.S.D. values of around 2 to 3%. Detection limits (38) were 6 ng ml⁻¹ for Cd, 3 ng ml⁻¹ for Cu and 16 ng ml⁻¹ for Pb. The method proposed was validated by the analysis of HPS 312205 seawater standard reference material and spiked mineral water samples.     

Amberlyst A-26 resin loaded with pyrocatechol violet—Preparation and applications as a preconcentrator in the atomic absorption spectrophotometric determination of lead and cadmium

Amberlyst A-26 loaded with pyrocatechol violet has been prepared and used for preconcentrating cadmium and lead before their flame atomic absorption Spectrophotometric determination. The optimum sorption pHs are 7.0–7.8 and 7.0–7.5 for Cd and Pb, respectively. The absorbance varies linearly in the concentration ranges of 0.1–1.0 and 1.5–7.5 μg cm⁻³, respectively, for the two metals. The sensitivity of the procedure for 1% absorption has been found to be 1.5 and 2.3 ng cm⁻³ of the solution to be analyzed, respectively, for Cd and Pb. The relative standard deviation is approximately 2.8%. The method has been used to determine Cd and Pb in the water of the Yamuna River (New Delhi, India) with a relative standard deviation between 4.3 and 5.1%.     

Instrumental neutron activation analysis of geochemical and cosmochemical samples: A fast and reliable method for small sample analysis

We have developed a fast and reliable procedure to routinely measure the abundances of up to about 35 elements even in small (<1 mg) samples. Depending on the type of samples, they are either irradiated for about 8 hours at a flux of about 2·10¹²n·cm^–2·s^–1, or up to 100 hours at a flux of about 6·10¹³n·cm^–2·s^–1. As standards, high-purity synthetic multielement standards and well-characterized geological reference materials are used. Synthetic standards are used as primary standards because they have several advantages over secondary (geological) standards. Three to four counts are done one each sample, starting 1–3 days after the end of the irradiation. We use high-purity germanium (HpGe) detectors with high efficiencies and very good energy resolution (1.6–1.8 keV at 1332 keV). To allow high throughput rates we use fast preamplifiers and gated integrator spectroscopy amplifiers with fast fixed conversion time ADCs. The signals are fed into an acquisition interface module (AIM) and via Ethernet into a Micro VAX. To allow better peak deconvolution, 8k spectra are taken where possible. A specially designed annular NaI(TI) guard detector allows Compton suppression spectrometry. The system uses standard software and was tested with sets of geological standards and has given reliable results for a wide variety of samples, e.g., cosmic spherules in the 30–200 g weight range.     

Cadmium and Lead Distribution in Marine Soil Sediments,Terrestrial Soil,Terrestrial Rock,and Atmospheric Particulate Matter around Split,Croatia

The distributions of cadmium and lead in marine sediments, surrounding soil, stones, and atmospheric particulate matter were determined at different locations in Split, Croatia. The determination of cadmium and lead was performed by flame atomic absorption spectrometry whereas atmospheric particulate matter samples were analyzed by inductively coupled plasma–optical emission spectrometry. Cadmium concentrations in the stones and soil were between 0.2 to 0.6 µg g^?1 and 0.2 to 0.9 µg g^?1. The concentration in the atmospheric particulate matter were <0.2 µg m^?2 d^?1(detection limit) to 1.4 µg m^?2 d^?1. Lead concentrations in marine sediments, stones, soil, and atmospheric particulate matter ranged from 31.2 to 144.4 µg g^?1, 9.3 to 29.4 µg g^?1, 11.3 to 66.1 µg g^?1, and 0.5 to 241.4 µg m^?2 d^?1, respectively. The relationship between determined parameters was established using principal component analysis and the results are in agreement with the assumption that anthropogenic sources play important roles for lead and cadmium distribution.     

Determination of heavy metals in soil, mushroom and plant samples by atomic absorption spectrometry

The concentrations of heavy metals in the soil, mushroom and plant samples collected from Tokat, Turkey have been determined by flame and graphite furnace atomic absorption spectrometry after dry ashing, wet ashing and microwave digestion. The study of sample preparation procedures showed that the microwave digestion method was the best. Good accuracy was assured by the analysis of standard reference materials. The relative standard deviations for all measured metal concentrations were lower than 10%. In all cases, quantitative analytical recoveries ranging from 95 to 103% were obtained. Metal accumulation factors were calculated for mushroom and plant samples. High ratio of plants to soil cadmium, zinc and copper concentrations indicate that these elements are accumulated by mushrooms. Results obtained are in agreement with data reported in the literature.     

Determination of bioavailable fractions of Zn, Cu, Ni, Pb and Cd in soils and sludges by atomic absorption spectrometry

The single extraction procedures validated by the standards, measurement and testing programme (formerly BCR), extraction with 0.05 mol l⁻¹ EDTA and 0.43 mol l⁻¹ acetic acid, have been applied to reference materials of soils and sludges with certified total values of elements, in order to determine bioavailable contents of Cd, Cu, Ni, Pb and Zn. These soils, which represent uncontaminated pedologically different types of soils from Slovakia and sludges from city water treatment are characterized for the bioavailable fraction of the metals using the procedures followed by SM&T Programme. Concentrations of the elements under the study in the extracts were determined by flame (FAAS) using calibration curves in appropriate extractants and by electrothermal (ETAAS) atomic absorption spectrometry, using technique of standard additions for the evaluation of the results. The accuracy of the extraction procedures and determinations of the elements in the extracts was controlled using CRM 483 certified for EDTA- and acetic acid-extractable contents of Cd, Cu, Ni, Pb and Zn in sewage sludge amended soil.     

Photometrische Zinnbestimmung in blei- und antimonhaltigen Bleilegierungen

Zusammenfassung Es wird über eine photometrische Methode berichtet, die es gestattet, Spuren von Zinn in Blei und antimonhaltigen Bleilegierungen schnell und genau zu bestimmen. Das Blei wird als Bleichlorid abgetrennt und das Filtrat fast zur Trockne eingedampft. Der Bückstand wird mit einer Lösung aus Natriumjodid (6,5 M) und Perchlorsäure (1 M) aufgenommen, aus der das Zinn selektiv mit Benzol extrahiert wird. Die photometrische Zinnbestimmung erfolgt mit dem sehr empfindlichen und fast spezifischen Reagens Hämatein. Nach dieser Methode können bis zu 2 · 10^–4% Sn in Blei bestimmt werden. Die Bestimmungsgrenze bei antimonhaltigen Legierungen ist abhängig von dem Antimongehalt. Bei einer Zinnkonzentration von 1,7 · 10^–2% in einer Bleilegierung mit 7% Sb beträgt die relative Standardabweichung ± 3%.

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Photometric determination of tin in lead and lead alloys containing antimony

Lead is separated as lead chloride and the filtrate is evaporated almost to dryness. The residue is dissolved in a solution of sodium iodide (6,5 M) and perchloric acid (1 M), and the tin is quantitatively extracted with benzene. For its photometric determination the very sensitive and highly selective reagent haematein is used. Up to 2×10^–4% tin in lead could be determined. The estimation limit in antimonial lead alloy depends upon the antimony content. With a tin concentration of 1.7×10^–2% in an antimonial lead alloy containing 7% Sb, the relative standard deviation corresponds to ± 3%.

     

Determination of traces of lead and cadmium in high-purity tin by polarized zeeman atomic-absorption spectrometry with direct atomization of solid sample in a graphite-cup cuvette

Lead at the mug g level and cadmium at ng g -mug g levels in high-purity tin have been determined by polarized Zeeman atomic-absorption spectrometry with direct atomization of the solid sample. Pieces of high-purity tin weighing up to 5 mg for lead and 20 mg for cadmium were analysed. Calibration graphs were constructed by use of standard solutions of lead and cadmium in the presence of pure tin having lead and cadmium contents below the detection limit. The tin matrix remained in the graphite-cup cuvette after atomization and did not adhere to the wall of the cuvette, so it could be easily removed and the same cuvette repeatedly used.     

Determination of Calcium and Copper in Feedstuffs by Atomic Absorption Spectrometry Following a Digestion Procedure with H2SO4 + H2O2

Feedstuffs can be effectively dissolved by treatment with concentrated sulfuric acid and 30% hydrogen peroxide in approximately 30 min for the rapid determination of elements at both the 1% level and the trace level by flame and electrothermal atomic absorption spectrometry, respectively. This paper reports a new determinative method for calcium (10 g · kg⁻¹) and copper (10 mg · kg⁻¹) based on this procedure. The relative standard deviation of the results was typically ca. 5%.