Determination of As, Ge, Hg, Pb, Sb, Se and Sn in coal slurries by CVG-ETV-ICP-MS using external or isotopic dilution calibration

A method for the multi-elemental determination of As, Ge, Hg, Pb, Sb, Se and Sn in coal reference materials by slurry sampling chemical vapor generation (CVG) using external calibration and isotopic dilution (ID) calibration and detection by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) is proposed. As, Ge, Sb, Se and Sn were determined using the external calibration, while, Hg, Pb, Se and Sn were determined by isotopic dilution. About 50–250 mg of sample was mixed with an acid solution, containing aqua regia and HCl, in an ultrasonic bath. For the isotopic dilution calibration, the enriched isotopes ²⁰¹Hg, ²⁰⁶Pb, ⁷⁷Se and ¹¹⁹Sn were added to the slurry in an adequate amount in order to produce an altered isotopic ratio close to 1. The vapor produced by the reaction of the sample slurry with the reducing agent was transported to the vaporizer and trapped in a Ir-treated graphite tube at 200 °C, before vaporization at 2100 °C and transportation of the vapor to the plasma. The accuracy of the method was assured by the analysis of four certified reference coal samples, using external calibration with aqueous solutions, prepared in the same medium and subjected to the same CVG and trapping procedure as the slurries and also by isotopic dilution calibration. The obtained concentrations were in agreement with the certified values, using the t-Student test for a confidence level of 95%. The detection limits (3 s; n = 5) of isotopic dilution, in ng g^− 1, were: 0.4 for Hg, 900 for Pb, 0.3 for Se and 0.2 for Sn. For external calibration, the detection limits, in ng g^− 1, were: 1.6 for As, 0.1 for Ge, 0.3 for Sb, 0.9 for Se and 7.5 for Sn. The relative standard deviations generally were lower than 14%, adequate for slurry analysis.     

Method development for the determination of cadmium,copper, lead,selenium and thallium in sediments by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry and isotopic dilution calibration

A procedure for the determination of Cd, Cu, Pb, Se and Tl by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) with calibration by isotopic dilution is proposed. The slurry is prepared by mixing the sample with diluted nitric and hydrofluoric acids in an ultrasonic bath and then in a water bath at 60 °C for 120 min. The slurries were let to stand at least for 12 h, manually shaken before poured into the autosampler cups and homogenized by passing through an argon flow, just before pipetting it into the furnace. The analytes were determined in two groups, according to their thermal behaviors. The furnace temperature program was optimized and the selected compromised pyrolysis temperatures were: 400 °C for Cd, Se and Tl and 700 °C for Cu and Pb. The vaporization temperature was 2300 °C. The analyses were carried out without modifier as no significant effect was observed for different tested modifiers. Different sample particle sizes did not affect the sensitivity significantly, then a particle size ≤50 μm was adopted. The accuracy was checked by analyzing five certified reference sediments, with analytes concentrations from sub-μg g⁻¹ to a few hundreds μg g⁻¹. The great majority of the obtained concentrations were in agreement with the certified values. The detection limits, determined for the MESS-2 certified sediment, were, in μg g⁻¹: 0.01 for Cd; 0.8 for Cu; 0.4 for Pb; 0.4 for Se and 0.06 for Tl. The precision was adequate with relative standard deviations lower than 12%. Isotopic dilution showed to be an efficient calibration technique for slurry, as the extraction of the analyte to the liquid phase of the slurry and the reactions in the vaporizer must help the equilibration between the added isotope and the isotope in the sample.     

Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge,As, Cd,Sb, Hg and Bi in cosmetic lotions

A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v l-cysteine, 0.5 μg mL⁻¹ Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng  g⁻¹ for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.     

Determination of hydride forming elements (As,Sb, Se,Sn) and Hg in environmental reference materials as acid slurries by on-line hydride generation inductively coupled plasma mass spectrometry

A method for the determination of As, Hg, Sb, Se and Sn in environmental and in geological reference materials, as acidified slurries, by flow injection (FI) coupled to a hydride generation system (HG) and detection by inductively coupled plasma mass spectrometry (ICP-MS) is proposed. The HG unit has a gas liquid separator and a drying unit for the generated vapor. The slurries were prepared by two procedures. Approximately 50 mg of the reference material, ground to a particle size ≤50 μm, was mixed with acid solutions in an ultrasonic bath. In Procedure A, the medium was a hydrochloric acid solution while in Procedure B, the medium was aqua regia plus a hydrochloric acid solution. The conditions for the slurry formation and the instrumental parameters were optimized. Harsh conditions were used in the slurry preparation in order to reduce the hydride forming analytes to their lower oxidation states, As (III), Se(IV), Sb(III) and Sn(II), before reacting with sodium tetrahydroborate. To test the accuracy, 10 certified reference materials were analyzed (four sediments, three coals, one coal fly ash and two sewage sludges), with the analyte concentrations mostly in the μg g⁻¹ level. Good agreements with the certified values were obtained for Hg, Sb and Sn in the sediments using Procedure A and calibration against aqueous standard solutions. Using Procedure B, good results were obtained for Hg, Se and Sn in the sediment samples, for Se in the coal and coal fly ash samples and for Hg in the sewage sludge samples, also using external calibration with aqueous standard solutions. For As in sediments, coals and coal fly ash, Procedure B and the analyte addition calibration was required, indicating matrix effects. The relative standard deviations were lower than 5%, demonstrating a good precision for slurry analysis. The limits of quantification (10 times the standard deviation; n=10), in the samples, in ng g⁻¹, were: 20 for As, 60 for Hg, 80 for Sb, 200 for Se and 90 for Sn. The method requires small amounts of reagents and reduces contamination and losses.     

Speciation of metallothionein-like proteins of the mussel Mytilus edulis by orthogonal separation mechanisms with inductively coupled plasma-mass spectrometry detection: effect of selenium administration

Several complementary separation mechanisms (size-exclusion chromatography, SEC; fast protein liquid chromatography, FPLC; reverse-phase chromatography, RPC) have been coupled to inductively coupled plasma mass spectrometry (ICP-MS) detection to investigate the speciation of Cd, Se, Cu and Zn in mussel hepatopancreas. SEC with double-focusing (DF) ICP-MS detection was used first for speciation analysis of those four trace elements, both in uncontaminated mussels and in mussels exposed to Cd (500 μg l⁻¹) or to Cd+Se (500 μg l⁻¹ of each element). Observed SEC results indicated that Se does not seem to significantly bind to metallothionein-like proteins (MLPs) ‘in vivo’. Total cytosolic Cd and MLPs content were lower in Cd+Se exposed mussels than those exposed to Cd only. For each treatment, 50 μl of the SEC peak fraction containing the MLPs was used to perform fast protein liquid chromatography coupled ‘on-line’ with a quadrupole (Q) ICP-MS. ⁸²Se and ¹¹⁴Cd isotopes were simultaneously monitored. Four and five Cd/MLPs isoforms were then detected in mussels exposed to only Cd and Cd+Se, respectively. In contrast, no signs of Se/MLP isoforms were found for both treatments. Subsequently, the bulk of MLPs eluting from the FPLC system were isolated and lyophilizated. A 50-μl aliquot of such reconstituted lyophilisate was then injected into a Vydac C₈ Reverse-Phase column directly connected to the Q-ICP-MS. Results confirmed the presence of one more Cd/MLP peak in those mussels exposed to Cd+Se. However, the number of Cd/MLP peaks detected decreased to three and four in only Cd and Cd+Se exposed animals, respectively. These results tend to indicate that Se, which does not trigger the biosynthesis of MLPs, could probably orient such synthesis towards the generation of a new Cd/MLP isoform in mussels submitted to both elements. The possible interrelation/complementation between Se and MLP against Cd toxicity is discussed.     

Occurrence of Volatile Metal and Metalloid Species in Landfill and Sewage Gases

Abstract

Speciation of volatile metals and metalloids in the environment is extensively described in literature. In order to investigate unstable volatile organometallics, on-line coupling of GC with ICP-MS was used. Preliminary results for gases of sewage sludge fermentation at thermophilic and mesophilic conditions are compared with the metal and metalloid speciation in landfill gases. In each case 20 L gas were sampled by cryogenic trapping. The species were identified by element-specific detection either by retention time of standards or by calculation of the boiling point correlation. Characteristic of the separation is the linear correlation of boiling point (bp/°C) versus retention time (rt/min) (bp = 6.39?rt -109.2, r² = 0.9926). The amounts of total volatile elements are estimated by semi-quantification. Cd, Sn. Hg, Pb (sewage gas) and Se, Te, Hg, Pb (landfill gas) were determined in the range of ng m^?3 level; As, Sb, Te and Bi (sewage gas) and As, Sn, Sb and Bi (landfill gas) in the μg m^?3 level range.     

Precise determination of cadmium and lead isotopic compositions in river sediments

A method for the accurate determination of Cd and Pb isotope compositions in sediment samples is presented. Separation of Cd and Pb was designed by using an anionic exchange chromatographic procedure. Measurements of Cd isotopic compositions were carried out by multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS), by using standard-sample bracketing technology for mass bias correction and Pb isotopic ratios were determined by thermal ionization mass spectrometry (TIMS). The factors that affect the accurate and precise Cd isotope compositions analysis, such as instrumental mass fractionation and isobaric interferences, were carefully evaluated and corrected. The Cd isotopic results were reported relative to an internal Cd solution and expressed as the δ^114/110Cd. Five Cd reference solutions and one Pb standard were repeatedly measured in order to assess the accuracy of the measurements. Uncertainties obtained were estimated to be lesser than 0.11‰ (2s) for the δ^114/110Cd value. Analytical uncertainties in 2s for Pb isotopic ratios were better than 0.5‰. The method has been successfully applied to the investigation of Cd and Pb isotope compositions in sediment samples collected from North River in south China.     

Simultaneous determination of hydride forming elements (As, Sb, Se, Sn) and Hg in sonicate slurries of biological and environmental reference materials by hydride generation microwave induced plasma optical emission spectrometry (SS-HG-MIP-OES)

A slurry sampling hydride generation (SS-HG) method for the simultaneous determination of hydride forming elements (As, Sb, Se, Sn) and Hg, without total sample digestion, has been developed using batch mode generation system coupled with microwave induced plasma optical emission spectrometry (MIP-OES) from certified biological and environmental reference materials. Slurry concentration up to 3.6% m/v (particles < 80 μm) prepared in 10% HCl containing 100 μl of decanol, by the application of ultrasonic agitation, was used with calibration by the standard addition technique. Harsh conditions were used in the slurry preparation in order to reduce the hydride forming elements to their lower oxidation states, As(III), Sb(III), Se(IV) and Sn(II) and Hg, being reduced to mercury vapor, before reacting with sodium tetrahydroborate. An ultrasonic probe was used to homogenize the slurry in the quartz cup just before its introduction into the reaction vessel. For 10 ml of slurry sample, detection limits (LOD, 3σ_blank, peak area) of 0.06, 0.08, 0.15, 0.12 and 0.10 μg g^− 1 were obtained for As, Sb, Se, Sn and Hg, respectively. The method offers relatively good precision (RSD ranged from 9 to 12%) for slurry analysis. To test the accuracy, three certified reference materials were analyzed with the analyte concentrations mostly in the μg g^− 1 level. Measured concentrations are in satisfactory agreement with certified values for the biological reference materials: NRCC LUTS-1 (lobster hepatopancreas), NRCC DOLT-2 (Dogfish Liver) and environmental reference material: NRCC PACS-1 (Marine Sediment), all adequate for slurry sampling. The method requires small amounts of reagents and reduces contamination and losses.     

Direct As,Bi, Ge,Hg and Se(IV) cold vapor/hydride generation from coal fly ash slurry samples and determination by electrothermal atomic absorption spectrometry

Direct cold vapor and hydride generation procedures for As, Bi, Ge, Hg and Se(IV) from aqueous slurry of coal fly ash samples have been developed by using a batch mode generation system. Ir-treated graphite tubes have been used as a preconcentration and atomization medium of the vapors generated. A Plackett–Burman experimental design has been used as a strategy for evaluation of the effects of several parameters affecting the vapor generation efficiency from solid particles, vapor trapping and atomization efficiency from Ir-treated graphite tubes. The effects of parameters such as hydrochloric acid and sodium tetrahydroborate, argon flow rate, trapping and atomization temperatures, trapping time, acid solution volume and mean particle size have been investigated. The significant parameters obtained (trapping and atomization temperatures for As and Ge; trapping temperature and trapping time for Bi; argon flow rate and atomization temperature for Se) have been optimized by 2²+star central composite design. For Hg, the trapping temperature has been also significant. Optimum values of the parameters have been selected for the development of direct cold vapor/hydride generation methods from slurry particles. The accuracy of methods have been verified by using NIST-1633a coal fly ash certified reference material. Absolute detection limits of 11.5, 48.0, 600, 55.0 and 11.0 ng l⁻¹ for As, Bi, Ge, Hg and Se have been achieved, respectively. A particle size less than 50 μm has shown to be adequate to obtain total cold vapor/hydride generation of metals content in the aqueous slurry particles.     

Determination of cadmium,mercury and lead in coal fly ash by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

Ultrasonic slurry sampling electrothermal vaporization isotope dilution inductively coupled plasma mass spectrometry (USS-ETV-ID-ICP-MS) has been applied to the determination of Cd, Hg and Pb in coal fly ash samples. Thioacetamide (TAC) was used as the modifier. Since the sensitivities of the elements studied in coal fly ash slurry and aqueous solution were quite different, isotope dilution method was used for the determination of Cd, Hg and Pb in these coal fly ash samples. The isotope ratios of each element were calculated from the peak areas of each injection peak. This method has been applied to the determination of Cd, Hg and Pb in NIST SRM 1633a coal fly ash reference material and a coal fly ash sample collected from Kaohsiung area. Analysis results of reference sample NIST SRM 1633a coal fly ash agreed satisfactorily with the certified values. The other sample determined by isotope dilution and method of standard additions was agreed satisfactorily. Precision was better than 6% for most of the determinations and accuracy was better than 4% with the USS-ETV-ID-ICP-MS method. Detection limits estimated from standard addition curves were in the range of 24–58, 6–28 and 108–110 ng g⁻¹ for Cd, Hg and Pb, respectively.     

Development of an ICP-IDMS method for accurate routine analyses of toxic heavy metals in polyolefins and comparison with results by TI-IDMS

An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method was developed as a suitable method – with respect to its sensitivity, precision, accuracy, and time-consumption – for the analysis of toxic heavy metal traces (Pb, Cd, Cr, and Hg) in polyolefins. Results for Pb, Cd, and Cr were compared with those obtained by thermal ionization isotope dilution mass spectrometry (TI-IDMS), which was used as a reference method. Because of its high first ionization potential and its high volatility mercury could not be determined by TI-IDMS. A multi-element spike solution, containing isotopically enriched ²⁰⁶Pb, ¹¹⁶Cd, ⁵³Cr, and ²⁰¹Hg, was used for the isotope dilution step. Decomposition of the polyolefin samples was carried out with concentrated HNO₃ at temperatures of about 300?°C in a high pressure asher (HPA). This procedure decomposes polyolefins completely and allows isotopic equilibration between sample and spike isotopes. Detection limits of 16 ng/g, 5 ng/g, 164 ng/g, and 9 ng/g were obtained for Pb, Cd, Cr, and Hg by ICP-IDMS using only sample weights of 0.25 g. In different commercially available polyethylene samples heavy metal concentrations in the range of < 5 ng/g to 4 × 10³ ng/g were analyzed. Both mass spectrometric methods were applied within the EU project “Polymeric Elemental Reference Material (PERM)” for the certification of two polyethylene reference materials. The ICP-IDMS results agreed very well with those of TI-IDMS which demonstrates the accuracy of the ICP-IDMS method also suitable for routine analyses.     

Thiodiethanethiol Modified Silica Coated Magnetic Nanoparticles for Preconcentration and Determination of Ultratrace Amounts of Mercury,Lead, and Cadmium in Environmental and Food Samples

A new magnetic adsorbent, 2,2′-thiodiethanethiol grafted with tetraethyl orthosilicate modified Fe₃O₄ nanoparticles, was developed for the separation and preconcentration of Hg, Pb, and Cd in environmental and food samples. The concentrations of Pb and Cd were determined by inductively coupled plasma–optical emission spectrometry; Hg was determined by cold vapor atomic absorption spectrometry. A comprehensive study on the factors affecting the extraction and desorption efficiencies was performed. Under the optimized conditions, the method was linear in the 0.01–750 ng mL^?1 range (before preconcentration) with detection limits of 4, 8, and 2 ng L^?1 for Hg, Pb, and Cd, respectively. Relative standard deviations of 2.3, 2.9, and 2.4% (concentration 50 ng mL^?1, n = 7) and high preconcentration factors of 291, 285, and 288 were also obtained for Hg, Pb, and Cd. The accuracy of the proposed method was validated by analyzing a water certified reference material with satisfactory recoveries. The method was successfully applied to the determination of the analytes in tap and mineral waters and canned tuna fish samples.     

Evaluation of the bioaccumulation of trace elements in tuna species by correlation analysis between their concentrations in muscle and first dorsal spine using microwave-assisted digestion and ICP-MS

Environmental pollution by metals is a recognized problem worldwide. As a result of the exposure to this pollution, marine species may bioaccumulate metals in both muscle and fishbone, as has been demonstrated in some species of tuna. The objective of this study has been the development and optimization of an inductively coupled plasma-mass spectrometry (ICP-MS) based method, which allows the quantification of 21 elements including priority pollutants and biologically essential elements (B, Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Pd, Cd, Ba, La, Hg and Pb) in muscle and in the first spine of the first dorsal fin of albacore (Thunnus alalunga) and bluefin tuna (Thunnus thynnus). A microwave-assisted digestion has been developed for sample treatment, which has been evaluated using isotope dilution analysis (IDA) of Cr, Se, Cd, Ba and Pb. Evaluation of the analytical method in terms of sensitivity (LOQ between 0.002 and 1?mg?kg^?1), accuracy and precision within and between days (CV?<?11.3%) has also been conducted. The developed method has allowed information to be obtained on levels of these metals in both matrices. The correlation analyses performed for each of the metals in both matrices shows a positive linear relationship between the concentrations in muscle and fishbone for Zn, Se, Rb, Cd, As and Hg, which could be due to a higher bioaccumulation of these elements in muscle as it is concluded from the low spine/muscle ratios observed for these elements. The 34 specimens of tuna analyzed show that while the levels of Pb, Cd, Ni, Zn, Cu and Cr in muscle are below the limits set by the WHO/FAO, EC and the US-EPA, Hg shows higher concentration than the limits set by the EC in four samples, indicating a potential risk to human health.     

Development of an accurate,sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine,sulfur, and heavy metals) in coal samples

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for ³⁵Cl⁺ to more than 6 × 10⁵ cps for ²³⁸U⁺ for 1 μg of trace element per gram of coal sample. Detection limits vary from 450 ng g⁻¹ for chlorine and 18 ng g⁻¹ for sulfur to 9.5 pg g⁻¹ for mercury and 0.3 pg g⁻¹ for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis. Figure LA-ICP-IDMS allows direct multi-element determination in powdered coal samples     

Determination of Hg,As, Pb,and Cd in Orchard Soils by Sequential Injection Vapor Generation Atomic Fluorescence Spectrometry

An analytical procedure was developed for determination of Hg, As, Pb, and Cd in soil samples using sequential injection vapor generation atomic fluorescence spectrometry (SI-VG-AFS) with sample preparation by microwave digestion system. The effects of analytical conditions on the fluorescence intensity were investigated and optimized. Under the optimized condition, the detection limits of the method were 5, 68, 40, and 3 ng L^?1 for Hg, As, Pb, and Cd, respectively. The accuracy of method was verified by the determination of the certified reference soil, and the recoveries for Hg, As, Pb, and Cd were in the range of 98.7–106.1%. The proposed method has been successfully applied to determine the heavy metals in navel orange orchard soils in Ganzhou, and the environmental quality of the orchard soils was assessed based on the content of the heavy metals. According to the second criterion of environmental quality standard for soils, Pb content in all soil samples collected from the orchards of 18 districts were within safe limits, but a few orchards were slightly contaminated with Hg, As, and Cd. Comparison of heavy metal mean concentrations with the safe limits of environmental quality standard for soils, the quality of Ganzhou navel orange orchard soils were in line with the request of the green food production base.     

Simultaneous electrochemical determination of arsenic, copper, lead and mercury in unpolluted fresh waters using a vibrating gold microwire electrode

In this work, a simple, rapid, reliable and low cost method for simultaneous electrochemical determination of As, Cu, Hg and Pb ions, on a vibrating gold microwire electrode combined with stripping voltammetry, is described for the first time.The multi-element detection was performed in the presence of oxygen by differential pulse anodic stripping voltammetry (DPASV) in HCl 0.1 M with NaCl 0.5 M. This media was found optimum in terms of peak resolution, peak shape and sensitivities, and has a composition similar to seawater to which the method could potentially be applied. The gold microwire electrode presented well defined, undistorted, sharp and reproducible peaks for trace concentrations of Cu, Hg and Pb and As presented a reproducible peak with a small shoulder. Using a gold vibrating microwire electrode of 25 μm diameter and 30 s deposition time, the detection limits of As, Cu, Hg and Pb were 0.07, 0.4, 0.07 and 0.2 μg L⁻¹, respectively. Possible effects of Al, Cd, Cr, Fe, Mn, Ni, Sb and Zn were investigated but did not cause any significant interferences.Finally, the method was applied for the simultaneous determination of these four metals in unpolluted river water samples and the results were validated by Atomic Absorption Spectroscopy with Electrothermal Atomization (AAS-EA) or by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).     

Isotopic fingerprint method: Assessment of the origin of rare earth compounds from the isotope ratios of lead impurities

The isotope ratios ²⁰⁷Pb:²⁰⁶Pb and ²⁰⁸Pb: ²⁰⁶Pb are measured by means of inductively coupled plasma mass spectrometry (ICP-MS) for monazite minerals and commercial rare earth compounds and are evaluated with respect to the initial composition of the minerals and the origin of the samples. The application of the isotopic fingerprint method is demonstrated.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday     

Use of enriched <Superscript>74</Superscript>Se and <Superscript>77</Superscript>Se in combination with isotope pattern deconvolution to differentiate and determine endogenous and supplemented selenium in lactating rats

A quantitative methodology has been developed to differentiate between endogenous and supplemented selenium in lactating rats using two enriched selenium isotopes. Lactating rats were fed for 2 weeks with formula milk containing one enriched Se isotope, ⁷⁷Se, as the metabolic tracer. The isotopic composition of selenium in serum and urine samples was then measured by collision cell ICP-MS after the addition of a solution containing another enriched isotope, ⁷⁴Se, as quantitation tracer, before analysis. Isotope pattern deconvolution allowed the transformation of measured Se isotopic abundances into concentrations of natural abundance (endogenous) selenium and enriched ⁷⁷Se (supplemented) present in the samples. The proposed methodology was validated using serum and urine reference materials spiked with both ⁷⁷Se and ⁷⁴Se. The obtained results are discussed in terms of selenium exchange and half-life in lactating rats (11–12 days) and selenium levels in serum in comparison with non-supplemented rats and control rats after maternal feeding.     

Certification of the contents of some heavy metals (Cd, Cu, Hg, Ni, Pb and Zn) in three types of soils

Summary The element contents of Cd, Cu, Hg, Ni, Pb and Zn of three types of soil were certified. The preparation, homogeneity and stability are reported. The certified contents as well as values for Co, Cr, Mn and Se and for the aqua regia soluble contents Cd, Cr, Cu, Mn, Ni, Pb and Zn are given.

---

Zertifizierung von Schwermetallspuren (Cd, Cu, Hg, Ni, Pb und Zn) in drei Bodenproben

Zusammenfassung In drei verschiedenen Bodenproben wurden die Elementgehalte an Cd, Cu, Hg, Ni, Pb und Zn zertifiziert. Es wird berichtet über die Bereitung, Homogenität und Stabilität. Die zertifizierten Gehalte sowie der Gehalt an Cr, Co, Mn und Se und der Gehalt an königswasserlöslichem Cd, Cr, Cu, Mn, Ni, Pb und Zn werden angegeben.

     

Inductively coupled plasma mass spectrometry for stable isotope tracer investigations

Inductively coupled plasma mass spectrometry (ICP-MS) has now been developed for application to stable isotope tracer investigations of several minerals/trace elements. Use of this method for such purposes requires an understanding of a number of fundamental issues: analytical chemistry performance of the method of isotopic analysis, relationship of the level of enriched isotope administered to the subject with background level of the isotope already present, the issues of cost, and finally the specific details of the biological issues to be explored.In this paper, a brief discussion of these issues is presented. As an example, the discussion is presented in relation to selected aspects of metabolism of selenium, employing the three stable isotopes⁷⁴Se,⁷⁷Se, and⁸²Se in the rat as the biological model.Analytical performance of hydride generation/ICP-MS is discussed for the required analyses of selenium isotopes. It is shown that for solutions containing 10 ng/ml Se of natural isotopic composition, optimized signal/background ratios greater than 40/1 can be obtained, resulting in worst-case detection limits (ng Se) of 2 (⁷⁴Se), and 0.6 (^77,82Se). The precision and accuracy of isotope ratio measurements for the method used routinely in biological studies is 1%. The accuracy of the method for quantitative isotopic analysis is compared with hydride generation/atomic absorption spectrophotometry (HG/AAS). The following results are given (g Se/g or ml; mean + 1 SD,n = 3–5; first HG/ICP-MS, second HG/AAS): SRM 1577a [bovine liver] 0.697 ± 0.002 versus 0.69 ± 0.01; human blood plasma 0.098 ± 0.001 versus 0.135 ± 0.008; human red cells 0.211 ± 0.002 versus 0.216 ± 0.012; and human urine 0.0473 ± 0.0003 versus 0.0489 ± 0.0003.An experiment is described with the rat to show the feasibility of the method for studies of selenium metabolism. Rats were placed on Se-free diet for eight weeks, given their Se requirements in the drinking water in the form of⁷⁶SeO ₃ ^2– and a single-day (day 3) replacement of their water with that containing highly enriched⁷⁴SeO ₃ ^2– . Isotopic analysis of carcass and selected organs revealed a high degree of isotopic enrichment with respect to⁷⁴Se during the entire eight weeks of the experiment, indicating the feasibility of this approach for detailed investigations of selenium metabolism in the rat.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria