Determination of Cd, Cu, Pb and Sb in environmental samples by ICP-AES using polyaniline for separation

The anion exchange properties of polyaniline for Cd, Cu, Pb and Sb in potassium iodide were studied. The analytes converted into anionic complexes by KI (0.03–0.96 mol/L) in HCl were adsorbed on polyaniline and eluted with HNO₃. The optimum conditions for adsorption and elution were determined. Quantitative recoveries were obtained for Cd, Cu and Pb, whereas, the recoveries for Sb were about 75%. This separation procedure was used with subsequent ICP-AES determination for Cd, Cu, and Pb in NIST-coal fly ash (1633b) and a sea plant with an R.S.D of 5% (n = 5).     

Studies on the determination of trace elements in high-purity Sb using GFAAS and ICP-QMS

Trace element impurities in high-purity antimony were determined employing three different methods for the removal of matrix; on Dowex 50WX 8 by adsorption from 0.1 mol/L HF and elution with 4 mol/L HNO₃; on Chelex-100 resin (in NH₄ ⁺ form) Bi, Cd, Co, Cu, and Pb were separated in the presence of tartaric acid at a pH of 9.0 ± 0.1 with subsequent elution with 2 mol/L HCl; these determinations were carried out by GFAAS. The separation of trace impurities from Sb by volatilization of the matrix from H₂SO₄ and HBr medium was also investigated. ICP-MS was used for the determination in these cases. All the three procedures showed that the removal of the antimony matrix was nearly quantitative (> 99.99%). The recoveries of trace elements were found to be > 95%. The relative standard deviations were in the range 2–7%. Standard addition calibrations were used. The levels of process blanks indicate that with careful optimization, the volatilization procedure coupled with ICP-QMS can be used for trace impurity characterization of 6N+ Sb. Received: 25 May 1998 / Revised: 23 September 1998 / Accepted: 26 September 1998     

Preconcentration of some metals using metalfix chelamine resin prior to ICP-AES analysis

Preconcentration and separation of Ni, Pb and Cd have been investigated using the metalfix chelamine resin prior to inductively coupled plasma – atomic emission spectrometry (ICP-AES) under various experimental conditions. The recoveries of the analytes obtained with 95% confidence level were 92 ± 1% for Ni, 100 ± 4% for Pb and 93 ± 3% for Cd. Received: 5 February 1998 / Revised: 30 April 1998 / Accepted: 12 June 1998     

Comparison of microwave-assisted acid leaching techniques for the determination of heavy metals in sediments, soils, and sludges

Microwave-assisted EPA method 3051 for nitric acid leaching of environmentally key elements from sediments, soils, and sludges was tested, and the influence of leaching temperature and time on element recovery for an estuarine sediment (CRM 277) was investigated. The extraction efficiencies for four certified reference materials applying EPA method 3051, an optimized nitric acid procedure, and an aqua regia (HCl/HNO₃ 3:1) procedure were compared. Digestions were carried out in a high-pressure microwave system offering simultaneous temperature and pressure control for all digestion vessels employed. Eight elements (Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn) were determined by ICP-AES and ICP-MS. Extraction efficiency strongly depended on the applied leaching parameters and varied for certain elements among different materials when a nitric acid procedure was applied. In general, element recoveries obtained from the aqua regia procedure were superior to those obtained from nitric acid procedures and showed good agreement with the 95% confidence interval of the certified value for most of the elements investigated. Received: 27 March 1998 / Revised: 29 June 1998 / Accepted: 3 July 1998     

Multi-elemental analysis of marine sediment reference material MESS-3: one-step microwave digestion and determination by high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS)

Single-step microwave digestion methods using four different acidic dissolving reagents were investigated with the main objective to obtain a simple, rapid method for multi-elemental analysis of marine sediment samples by high resolution inductively coupled plasma-mass spectrometry (HRICP-MS), especially for environmental studies. Closed-vessels microwave digestion procedures were carried out using the reagents as follows: HNO₃, mixture of HNO₃-HCl (φ _r = 9: 1), aqua regia, and mixture of HNO₃-HCl-HF (φ _r = 8: 1: 1). The elements analyzed were: Al, As, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, K, Li, Mn, Mo, Na, Ni, Pb, Sb, Sn, Sr, Ti, Tl, V, and Zn. Good recoveries were established for many of the metals analyzed even when only nitric acid was employed. However, for a good recovery of Sb and Tl, aqua regia should be employed.     

Extraction systems of flame atomic absorption determination of trace impurities in high purity nickel salts

Summary Different extraction sytems including long chain quaternary alkylammonium salts and APDC were investigated in order to determine the optimal conditions for extraction separation and preconcentration of traces of Ag, Bi, Cd, Cu, Fe, Mo, Pb, Sb and Zn from high purity NiSO₄·6H₂O, NiCl₂·6H₂O, Ni(OOCCH₃)₂·4H₂O and Ni(NO)₃)₂·6 H₂O. Best results for multielement preconcentration were found with the extraction system HCl-trioctylmethylammonium chloride-0,002 mol/l APDC/MIBK. The proposed method permits the flame atomic absorption determination of 5·10^–6%, Ag, Cd, Cu and Zn, 1·10^–5% Bi, Fe, Pb and 5·10^–5% Mo and Sb with good accuracy and precision.     

Studies on the determination of trace elements in high-purity Sb using GFAAS and ICP-QMS

Trace element impurities in high-purity antimony were determined employing three different methods for the removal of matrix; on Dowex 50WX 8 by adsorption from 0.1 mol/L HF and elution with 4 mol/L HNO₃; on Chelex-100 resin (in NH₄ ⁺ form) Bi, Cd, Co, Cu, and Pb were separated in the presence of tartaric acid at a pH of 9.0 ± 0.1 with subsequent elution with 2 mol/L HCl; these determinations were carried out by GFAAS. The separation of trace impurities from Sb by volatilization of the matrix from H₂SO₄ and HBr medium was also investigated. ICP-MS was used for the determination in these cases. All the three procedures showed that the removal of the antimony matrix was nearly quantitative (> 99.99%). The recoveries of trace elements were found to be > 95%. The relative standard deviations were in the range 2–7%. Standard addition calibrations were used. The levels of process blanks indicate that with careful optimization, the volatilization procedure coupled with ICP-QMS can be used for trace impurity characterization of 6N+ Sb.     

The certification of the contents of Cd, Co, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se, Tl and Cr in a city waste incineration ash

Summary The analysis of ashes being of increasing importance, a reference material was prepared from fly ash of a city waste incinerator. The procedures of preparation, homogeneity and stability testing are described as well as the way of certification of elements of major importance: Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se and Tl.

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Zertifizierung der Gehalte an Cd, Co, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se, Tl und Cr in einer Stadtmüll-Verbrennungsasche

Zusammenfassung Da die Analyse von Aschen zunehmend an Bedeutung gewinnt, wurde von der Flugasche einer Stadtmüll-Verbrennungsanlage ein Referenzmaterial hergestellt. Die Methoden der Herstellung sowie der Homogenitätsund Stabilitätsprüfung werden beschrieben und die Art der Zertifizierung der Elemente von hauptsächlicher Bedeutung aufgezeigt (Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se, Tl).

     

Liquid Cathode Glow Discharge as a Microplasma Excitation Source for Atomic Emission Spectrometry for the Determination of Trace Heavy Metals in Ore Samples

A novel liquid cathode glow discharge (LCGD) was designed as a microplasma excitation source for atomic emission spectrometry (AES) and used for the determination of Pb, Cu, and Cd in digested ore samples. The operating parameters and stability of LCGD-AES were investigated in detail. The statistical analysis (t-test) was used for comparing the results of ore samples using LCGD-AES and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that the optimized analytical conditions are 650?V discharge voltage, 4.5?mL?min^?1 solution flow rate, and pH 1 HNO₃ as the supporting electrolyte. The limits of detection for Pb, Cu, and Cd were 0.019, 0.47, and 0.37?mg?L^?1, respectively. The correlation coefficients and relative standard deviations were 0.9985 and 1.19% for Pb, 0.9868 and 2.37% for Cu, and 0.9960 and 3.98% for Cd. The power consumption was below 65?W. The recoveries were in the range from 79.1 to 115.1%. Moreover, the measurement results of ore samples by LCGD-AES are comparable to the values obtained by ICP-AES. Therefore, the LCGD-AES may be developed as a portable analytical instrument for the direct determination of trace heavy metals.     

New sorbents and indicator powders for preconcentration and determination of trace metals in liquid samples

Two approaches to immobilize complex-forming analytical reagents (PAN, PAR, Xylenol orange, Brombenzothiazo, Crystal violet, Cadion, and Sulfochlorophenolazorhodanine) for the preparation of new sorbents and indicator powders are suggested: on-line coating of reversed-phase silica gel by reagents or doping of porous sol-gel silica with reagents. The retention of Ag, Cd, Cu(II), Co(II), Fe(III), Mn(II), Ni, Pb, and Zn on the sorbents developed was investigated. Quantitative sorption and desorption conditions were optimized. Procedures for the determination of Cd, Cu(II), Fe(III), Pb, and Zn with flame atomic absorption, spectrophotometric, and diffusion scattering spectrometric detection were elaborated. Detection limits for Cd, Cu(II), Fe(III), Pb, and Zn were 3 μg/L, 6 μg/L, 5 μg/L, 40 μg/L, and 1 μg/L, respectively. The procedures were used for the analysis of various real samples, e.g., natural and waste waters, and food. Received: 17 July 1997 / Revised: 20 January 1998 / Accepted: 5 February 1998     

Polarographic determination of Cu, Cd, Pb, Bi and Tl in succinic acid

Summary Copper, cadmium, lead, bismuth, and thallium develop well defined polarograms in 0.1 M succinic acid at pH 3.0 in presence of 0.005% gelatin (except Cu which requires 0.01% gelatin). The polarograms of all these metal ions are diffusion controlled with E _1/2 at –0.07 V, –0.60 V, –0.43 V, –0.11 V, and –0.50 V vs. S.C.E., respectively. Since the half wave potentials of some of the metal ions are well separated, their simultaneous polarographic determination is possible (Cu/Pb, Bi/Pb, Pb/Zn, Cu/Cd).

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Polarographische Bestimmung von Cu, Cd, Pb, Bi und Tl in Bernsteinsäurelösung

Zusammenfassung Die genannten Metalle liefern gut ausgebildete diffusionskontrollierte Polarogramme in 0,1 M Bernsteinsäurelösung bei pH 3,0 in Gegenwart von 0,005% Gelatine (0,01% bei Cu). Die Halbstufenpotentiale betragen: –0,07 V, –0,60 V, –0,43 V, –0,11 V bzw. –0,50 V (gegen GKE). Da sie teilweise gut voneinander getrennt sind, können Bestimmungen dieser Metalle nebeneinander ausgeführt werden (Cu/Pb, Bi/Pb, Pb/Zn, Cu/Cd).

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Our sincere thanks are due to Dr. G. B. Singh, Professor and Head, Dept. of Chemistry, B. H. U., for providing the necessary facilities.     

Preconcentration procedure for determining trace amounts of Ni,Cd, Pb and Cu in high-salinity waters after cloud-point extraction

A procedure for determination of Cd, Pb, Cu and Ni in high-salinity waters by inductively coupled plasma optical emission spectrometry has been developed. It is based on cloud-point extraction of these metals as complexes of diethyldithiocarbamate (NaDDTC) in micellar media of non ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). Multivariate optimisation techniques have been applied to optimise the experimental variables. A full two-level factorial design was used to evaluate the influence of variables and Doehlert design was performed to find the optimum values. The effect of interference from residual salinity in surfactant-rich phase was also investigated. The developed procedure allows to achieve enhancement factors of 20.0, 20.4, 19.5 and 20.6, along with limits of detection (3σ _B) of 0.030, 2.1, 0.62 and 0.27 µg L^?1, and precision expressed as relative standard deviation (%RSD, n = 10) of 3.7 (40.0 µg L^?1), 5.7 (20.0 µg L^?1), 6.6 (20.0 µg L^?1) and 3.1% (10.0 µg L^?1) for Cd, Pb, Cu and Ni, respectively. The accuracy was evaluated by spike tests on the seawater (salinity of 35‰) and petroleum produced formation waters (salinity between 15‰ and 75‰). It was obtained by recoveries between 79% and 105%.     

Inductively Coupled Plasma Mass Spectrometry for Sequential Determination of Trace Metals in Rain and River Waters Using Electrothermal Vaporization

Abstract

The sequential determination of 14 trace metals, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, Cd, Sb and Pb, in rain and river water samples has been investigated using an inductively coupled plasma mass spectrometry (ICP-MS) with a graphite rod electrothermal vaporizer (ETV) in the presence of the mixed modifier of palladium nitrate and magnesium nitrate. The sensitivity enhancements due to the presence of the modifier were observed for all analyte elements. Detection limits as high as 0.52, 0.13, 0.89, 0.35, 1.76, 0.5, 0.9, 0.5, 0.04, 1.03, 0.28, 0.07, 0.1 and 3.78 pg, respectively, for Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, Cd, Sb and Pb have been achieved. For the determination of trace metals in both rain and river water samples by this method, the repeatibility of sample solution were very good, i.e. from 1% to 7% (as a coefficient variation) and the recoveries of elements were good enough, i.e. from 81% to 106%, by using a standard addition method. There was no difference between the results obtained by nebulizer ICP-MS and those obtained by this method, except for zinc and arsenic.     

A Sequential Extraction Method Measures the Toxic Metal Content in Fly Ash from a Municipal Solid Waste Incinerator

The purpose of this research was to develop an optimized pretreatment procedure for toxic metals (Pb, Cd, Zn and Cu) content in fly ash from a municipal waste incinerator. In addition, modified sequential extraction procedures were used to characterize the chemical composition of the fly ash samples. The sequential extraction resolved the fly ash elements into the following chemical forms: soluble, exchangeable, carbonate, oxide, organic, and silicate compounds. Certified reference city waste incineration ash (BCR.176) was used as target ash samples. A H₂O₂+HNO₃+HF mixed acid digestion solution with a low temperature evaporation procedure was selected as optimal for the fly ash digestion. The digested solution was analyzed by inductively coupled plasma mass spectrometry (ICP‐MS), which effectively determined the concentrations of the toxic metal elements in BCR.176. Except for Cd, the recovery of Pb, Zn, and Cu under H₂O₂+HNO₃+HF digestion and their sequential extraction procedures were higher than 95%. The relative standard deviations (RSD) for recoveries of the four elements were within 10%. Furthermore, the sequential extraction procedure's results provided information on the potential mobility of the studied elements. Most of the Cd was bound to water‐soluble and carbonate material in the fly ash samples. Most of the Pb, Zn, and Cu was released to carbonates and bound to organic matter in the fly ash samples.     

Assessment of trace elements characteristics and human health risk of exposure to ambient PM2.5 in Hangzhou,China

A method for simultaneously determining the trace elements in particulate matter (PM) (PM2.5) by inductively coupled plasma mass spectrometry was established. The PM2.5-loaded filter samples were digested under the optimised conditions including a mixture of HNO₃–HCl–HF with ultrasonication proceeding at 70°C for 2 h. Recoveries of 90.83–103.33% were achieved for 20 elements (Co, Sr, Ag, Cd, Sb, La, Ce, Sm, W etc.) in NIST standard reference material 1648a (urban PM). PM2.5 samples were collected at urban site in Hangzhou from August 2015 to November 2015. PM2.5 concentrations of 15% sampling days exceeded the daily limitation and the mean concentrations of PM2.5 from August to November reached the 66.4% of the limitation. PM2.5 concentrations in summer were higher than that in autumn. The concentration of Zn was highest, following with Al, Pb, Mn, Cu and As. Significant enrichment was observed in Mn, Zn, Pb, Ag, V, Ni, Cu, As, Se, Hg, Co, Cd and W, which was probably induced by vehicular exhaust, oil and residual fuel combustion and industrial emissions. The daily mass concentrations of PM2.5 and elements fluctuated significantly. Rainfall could significantly reduce the concentration of Ti, Mn, Cu, Zn, As, Se, Hg, Sr, Ag, Cd, Sb, La, Ce, Sm and Pb, and the risk levels of carcinogenic elements and non-carcinogenic elements in rain day were significantly lower (43.7–81.4%) than those in non-rain day. The risk levels of Co, Cd and As could lead to adverse health outcomes through the respiratory system, which should deserve more attention, while the risk levels of Ni and non-carcinogenic elements (Hg, Mn, Cu, Zn, Pb, V) were under average risk acceptance.     

Analytische Anwendung der Di-thiobenzhydrazone von 1,2-Diketonen

Zusammenfassung Die Anwendung der Di-thiobenzhydrazone von 1,2-Dicarbonylverbindungen zur Extraktion und zur spektralphotometrischen Bestimmung von Metallionen wurde untersucht. Danach bilden die 1,2-Bisthiobenzhydrazone farbige, in organische Lösungsmittel extrahierbare Chelate ( _M=3000–14000) mit Pb(II), mit Elementen der 1., 2. und 8. Nebengruppe, vereinzelt mit In(III), häufiger mit Sb(III) und mit Bi(III). Die Chelatbitdung von Diacetyl-bis-thiobenzhydrazon und von 2,3-Pentandion-bis-thiobenzhydrazon-p-methoxy mit Cu(II), Zn(II), Cd(II), Hg(II) und Pb(II) wurde als Beispiel näher untersucht.

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Analytical application of 1,2-diketo-bis-thiobenzhydrazones

The application of 1,2-diketo-bis-thiobenzhydrazones as ligands for the extraction and spectrophotometric determination of metal ions has been studied. The 1,2 bisthiobenzhydrazones form highly coloured ( _M=3–14×10³) and with organic solvents easily extractable chelates with Pb(II), In(III), Sb(III), Bi(III) and elements of the Ist, 2nd and 8th subgroup. The application of diacetyl-bis-thiobenzhydrazone and 2,3-pentanedione-bis-(p-methoxy)-thiobenzhydrazone for the determination of Cd(II), Cu(II), Hg(II), Pb(II) and Zn(II) has been studied in detail.

     

Determination of picomole amounts of formaldehyde in air and bio-fluids based on its enhanced myoglobin-luminol chemiluminescence reaction

Abstract

The aim of this study was to assess the performance of selected destruction methods for the determination of heavy metals (Cd, Cu, Pb and Zn) in woodlouse (Oniscus asellus). A vigorous total analysis involving microwave destruction with HF, HCl and HNO₃ (method 1) was used as a reference method. Consistently low values for the dry ashing method may indicate incomplete dissolution of the elements and/or losses through volatilisation. Method 3 (concentrated HNO₃) that frequently is used in literature, produced erroneous values for Cd, Cu and Pb. Results were consistent with the microwave digestion, provided H₂O₂ was used during digestion (method 4, HNO₃/H₂O₂). Method 5 (HNO₃/HCIO₄, one destruction step) yielded low recoveries when only one destruction step was applied. Applying two destruction steps (method 6) resulted in values consistent with the microwave method, but was at the expense of reproducibility and rendered the method more lengthy and laborious. Because of the very good performance combined with speed and simplicity, destruction with HNO₃/H₂O₂ (method 4) emerged as the most convenient method.     

Preparation and testing of standard solutions of cadmium, copper and lead

 Solutions of Cd, Cu and Pb at concentrations of about 1000 mg/l were prepared by dissolving the pure metals in HNO₃. Their concentration was verified by complexometric titration and by gravimetric analysis (Cu with salicylaldoxime, Cd with quinaldinic acid and Pb with 8-hydroxyquinoline). The results of the two methods were very similar and the uncertainty values were equal. However, the gravimetric determination can be regarded as more reliable, because titrimetric analysis is more prone to error due to inaccurate end-point reading. The expanded uncertainty of the concentrations of Cd and Cu attained 1 mg/l, which is half the value typically obtained for similar solutions from commercial manufacturers. To achieve such precise results, the bias had to be reduced by the highest possible extent, particularly by calibrating both the balance and the volumetric glassware. In addition to the uncertainty of the basic operations (volumetric and gravimetric), the uncertainty of the atomic and molecular weights constituted an appreciable component in the combined standard uncertainty; this manifested itself in the determination of Pb, where the expanded uncertainty was 2 mg/l. Received: 24 September 1998 / Accepted: 25 January 1999     

Determination of cadmium and lead in mussels by electrothermal atomic absorption spectrometry using an ultrasound-assisted extraction method optimized by factorial design

A simple and rapid method is described for the quantitative extraction and determination of Cd and Pb in mussel tissue (Mytilus edulis). The method is based on the quantitative ultrasound-assisted extraction (i.e. sample mass at mg level) of the two metals using diluted nitric acid as extractant. The extraction procedure is carried out in autosampler cups of the graphite furnace (typically, less than 20 mg). A two-level full factorial design (2⁴) was applied to optimize the variables influencing the ultrasound extraction process. These variables were: extraction time, ultrasound amplitude, nitric acid concentration and particle size. Optimization results showed that acid concentration and particle size were the more significant variables. Determination of Cd and Pb in extracts obtained after ultrasound treatment was carried out by Electrothermal Atomic Absorption Spectrometry. The method was validated by statistically comparing the metal contents found with the certified ones corresponding to the BCR 278 mussel tissue. No significant differences were observed for P = 0.05. LODs for Cd and Pb in mussel tissue were 0.019 and 0.37 μg g^–1. RSDs values (corresponding to between-batch precision for n = 5) were 2.2 and 6.7% for Cd and Pb, respectively. The method was applied to measure the contents of Cd and Pb in mussels used as pollution bioindicators from the Galician coast (Ria de Vigo, Spain). Received: 30 June 1998 / Revised: 17 September 1998 / Accepted: 22 September 1998