Field Inductively Coupled Plasma Mass Research Articles

Boron Isotopic Ratio (δ11B) Measurements in Boron Carbide (B4C): Benchmarking Between SF-ICP-MS and PIGE Techniques

The results of comparing the analytical capabilities of Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) and Particle Induced Gamma-ray Emission (PIGE) methods for determining the 11B/10B isotope ratio in boron carbide samples (B4C) are presented. The following nuclear reactions excited by protons on the stable boron isotopes are considered: 10B(p,aγ)7Be, 10B(p,pγ)7Be and 11B(p,γ)12C. The optimum proton energy range was determined to be within 550 to 600 keV, while the energies of the induced gamma-radiation that can be used for quantitative estimation of the boron isotopes were 429 keV and 4439 keV for the isotopes 10B and 11B, respectively. Considering the uncertainties of measurements, the data for the 11B/10B isotope ratios, measured by the SF‑ICP‑MS and PIGE methods, are found to correlate with each other; yet they are characterized by a systematic bias. The uncertainty of measurements by the PIGE method was somewhat higher in comparison with SF-ICP-MS, and ranged from ± 4.1 % to ± 4.3 %, and from ± 1.1 % to ± 3.5 %, respectively.

Distribution of plutonium isotopes in soils between two nuclear test sites: Semipalatinsk and Lop Nor

Plutonium (Pu) has attracted attention as an environmental tracer due to its radiotoxicity and the possibility of sources linked with nuclear accidents in recent years. Plutonium isotopes (239,240Pu) were detected at trace levels in soils collected from the Xinjiang region located between the Semipalatinsk nuclear test site and China's Lop Nor nuclear test site. Little is known regarding the spatial variation of 239,240Pu in soils from this region. This study reports the use of Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) methods to distinguish between Pu isotopes derived from global fallout and nuclear weapon tests. We found that the 239,240Pu activity concentrations ranged from 0.035 to 1.338 mBq/g; the 240Pu/239Pu atomic ratios were 0.157–0.223 with a weighted average of 0.180 ± 0.002, corresponding with the expected average global fallout ratio of 0.180 ± 0.014. This indicated that global fallout is the major source of Pu in the study region. The 239,240Pu inventories in these soils ranged from 23.67 to 222.7 Bq/m2, corresponding with those from other areas in China and other countries within the latitude range. Our Pu isotope data was supplemented with other published Pu data for soils collected in the vicinity of the Semipalatinsk nuclear test site and Lop Nor nuclear test site. Results indicate that 239,240Pu inventories and 240Pu/239Pu atomic ratios in soils exhibit large variations with distance from the Semipalatinsk nuclear test site. High deposition and accumulation of Pu, and low 240Pu/239Pu ratios were observed in close-in fallout and downwind regions of the Semipalatinsk nuclear test site and China's Lop Nor nuclear test site.

Simultaneous determination of mercury, cadmium and lead in fish sauce using Diffusive Gradients in Thin-films technique

Fish sauce is a popular seasoning liquid originating from southeastern Asian cuisine, consisting of fermented fish, salt and additional ingredients. Fish can contain high amounts of metals, some of which are hazardous for human health. Therefore, authorities responsible for food safety and quality should monitor the levels of these contaminants in fish and fish deviated products. In this work, the passive sampling technique of Diffusive Gradients in Thin-films (DGT) containing Chelex-100 and Purolite S924 resin gels, is used for the determination of dissolved mercury (Hg), cadmium (Cd) and lead (Pb) in fish sauce. The DGT performance test showed linear accumulation of Hg, Cd and Pb on the binding gels versus deployment time. A wide range of pH and salt concentration did not affect the performance of the DGT. The effective diffusion coefficients of Hg, Cd and Pb in diffusive gels were determined by applying a series of deployments in fish sauce solution. Besides the direct sampling with the DGT technique, fish sauce samples were also digested using a microwave oven. Analyses of DGT and microwave oven digested samples were performed with Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS). Both methods were then used for the analysis of fish sauces from local retail stores. Due to the preconcentration ability of DGT, lower detection limits of Hg, Cd and Pb could be achieved compared to the microwave digestion method. The DGT technique offers a more sensitive method for trace element analysis in complex food matrices.

Determination of Cl, Br, and I in Geological Materials by Sector Field Inductively Coupled Plasma Mass Spectrometry.

In this study, a simple and effective method for the simultaneous analysis of Cl, Br, and I in geological materials based on NH4HF2 digestion in open vessels (Savillex Teflon vials) is proposed. It is very interesting to note that Cl, Br, and I are not lost during NH4HF2 digestion at temperatures of 200-240 °C for 0.5-12 h in open vessels. This should be related to the alkaline atmosphere environment caused by the NH3 produced during NH4HF2 digestion, which suppresses the volatilization loss of Cl, Br, and I. A 100 mg sample of geological materials can be completely digested by using 400 mg of NH4HF2 at 220 °C for 2 h in Savillex Teflon vials. The use of new Savillex Teflon vials significantly reduced the procedural blanks of halogens compared with the old Savillex Teflon vials. The developed method was successfully applied to the simultaneous determination of Cl, Br, and I in a series of international geological reference materials. Most of the results were found to be in reasonable agreement with values reported in the literature. This simple, rapid, effective, and economical analytical method will significantly promote the development of halogen geochemistry.

Determination of Trace Elements in High Purity Silver Granules Using Sector Field Inductively Coupled Plasma Mass Spectrometry

Abstract The trace impurities in high-purity silver granules were determined by fast scanning single collector sector field high-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) after selective separation of the major matrix and silver as silver metal by hydroxylamine hydrochloride. In the filtrate, 32 major and minor metallic impurities including silver were determined using NIST SRM 1643e, Trace Elements in Water, VHG SM75 and SM90 (VHC Labs, Inc., Manchester, NH), and internal standards 7Li, 9Be, 45Sc, 72Ge, 115ln, 209Bi, and 238U. To minimize the matrix effect, reagent blank was measured and subtracted from the samples. The spectral interferences have been resolved by measuring the isotopes 55Mn, 56Fe, 75As, and 78Se in high-resolution mode (m/Δm = 10,000); 52Cr, 63Cu, and 64Zn in medium-resolution mode (m/Δm = 4,000); and others in low-resolution mode (m/Δm = 300). In the present study, the purity of the tested silver granules was found to be 99.9898 ± 0.00007 % with 95 % confidence level. The purity results obtained from impurity assessment by HR-ICPMS were compared with those of the results of the conventional gravimetric method and found to be comparable. Though the gravimetric process is a primary technique for purity determination and the results obtained are directly traceable to SI units, HR-ICPMS provides more information about the impurities present in the silver granules. The proposed method is convenient, accurate, and precise and can be used for purity as well as for determination of trace impurities in silver metal.

Copper Ion Assisted Photochemical Vapor Generation of Chlorine for Its Sensitive Determination by Sector Field Inductively Coupled Plasma Mass Spectrometry.

A novel, reliable, and sensitive approach for the determination of chlorine by sector field inductively coupled plasma mass spectrometry (SF-ICPMS) using photochemical vapor generation for sample introduction is presented. Methyl chloride is generated from different chlorine species in a flow-through photochemical reactor using a 1% solution of acetic acid containing 7.5 μg g-1 of Cu2+. The volatile product is directed by an argon carrier gas to a gas-liquid separator and introduced into the instrument. A sample flow rate at 1.7 mL min-1 and a 45 s irradiation time provided a 74-fold enhancement in sensitivity compared to conventional nebulization. A blank-limited detection limit of 0.5 ng g-1 for chloride, suitable for quantitation at trace levels, was achieved. The proposed method was validated by analysis of two certified reference materials, NIST SRM 1568b rice flour and SRM 1571 orchard leaves, with satisfactory results, as well as three varieties of bottled water, achieving spike recoveries between 101% and 105%.

Changes in oxidative potential of soil and fly ash after reaction with gaseous nitric acid

The goal of this study was to examine the impact of simulated atmospheric aging on the oxidative potential of inorganic aerosols comprised primarily of crustal materials. Four soil samples and one coal fly ash sample were artificially aged in the laboratory through exposure to the vapor from 15.8 M nitric acid solution for 24 h at room temperature. Native and acid-aged samples were analyzed with a cellular macrophage and acellular dithionthreitol assays to determine oxidative potential. Additionally, the samples were analyzed to determine the concentration of 50 elements, both total and the water-soluble fraction of these elements by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICMS) and crystalline mineral composition using X-ray Diffraction (XRD). The results show that reactions with gaseous nitric acid increase the water-soluble fraction of many elements, including calcium, iron, magnesium, zinc, and lead. The mineral composition analysis documented that calcium-rich minerals present in the soils (e.g., calcite) are converted into different chemical forms, such as calcium nitrate (Ca(NO3)2). The nitric acid aging process, which can occur in the atmosphere, leads to a 200–600% increase in oxidative potential, as measured by cellular and acellular assays. This laboratory study demonstrates that the toxic effects of aged versus freshly emitted atmospheric dust may be quite different. In addition, the results suggest that mineralogical analysis of atmospheric dust may be useful in understanding its degree of aging.

Development of procedure for measurement of Pb isotope ratios in seawater by application of seaFAST sample pre-treatment system and Sector Field Inductively Coupled Plasma Mass Spectrometry

Anthropogenic Pb in the oceans, derived from high-temperature industrial processes, fuel combustion and incineration can have an isotopic signature distinct from naturally occurring Pb, supplied by rock weathering. To identify the different pollution sources accurately and to quantify their relative contributions, Pb isotope ratios are widely used.Due to the high salt content (approximately 3.5% of total dissolved solids) and very low levels of Pb (typically from 1 to 100ngL−1) in seawater the determination of Pb isotope ratios requires preliminary matrix separation and analyte preconcentration. An analytical protocol for the measurements of Pb isotope ratios in seawater combining seaFAST sample pre-treatment system and Sector Field Inductively Coupled Plasma Mass Spectrometry (SF ICP-MS) was developed. The application of seaFAST system was advantageous, because of its completely closed working cycle and small volumes of chemicals introduced in pre-treatment step, resulting in very low detection limits and procedural blanks.The preconcentration/matrix separation step was also of crucial importance for minimizing the isobaric and matrix interferences, coming from the seawater. In order to differentiate between anthropogenic and natural Pb sources, particular attention was paid to the determination of 204Pb isotope because of its implication in some geological interpretations.The validation of the analytical procedure was effectuated according to the recommendations of the ISO/IEC 17025 standard. The method was validated by processing the common Pb isotope reference material NIST SRM 981. All major sources of uncertainty were identified and propagated together following the ISO/GUM guidelines. The estimation of the total uncertainty associated to each measurement result was fundamental tool for sorting the main sources of possible biases. The developed analytical procedure was applied to the coastal and open seawater samples, collected in different regions of the world and revealed that the procedure is applicable for the measurement of Pb isotope ratios in seawater with combined uncertainty adequate to discuss the origin of Pb pollution in the ocean.

High-Resolution Inductively Coupled Plasma Optical Emission Spectrometry for (234)U/(238)Pu Age Dating of Plutonium Materials and Comparison to Sector Field Inductively Coupled Plasma Mass Spectrometry.

Employing a commercial high-resolution inductively coupled plasma optical emission spectrometry (HR-ICP-OES) instrument, an innovative analytical procedure for the accurate determination of the production age of various Pu materials (Pu powder, cardiac pacemaker battery, (242)Cm heat source, etc.) was developed and validated. This undertaking was based on the fact that the α decay of (238)Pu present in the investigated samples produced (234)U and both mother and daughter could be identified unequivocally using HR-ICP-OES. Benefiting from the high spectral resolution of the instrument (<5 pm) and the isotope shift of the emission lines of both nuclides, (234)U and (238)Pu were selectively and directly determined in the dissolved samples, i.e., without a chemical separation of the two analytes from each other. Exact emission wavelengths as well as emission spectra of (234)U centered around λ = 411.590 nm and λ = 424.408 nm are reported here for the first time. Emission spectra of the isotopic standard reference material IRMM-199, comprising about one-third each of (233)U, (235)U, and (238)U, confirmed the presence of (234)U in the investigated samples. For the assessment of the (234)U/(238)Pu amount ratio, the emission signals of (234)U and (238)Pu were quantified at λ = 424.408 nm and λ = 402.148 nm, respectively. The age of the investigated samples (range: 26.7-44.4 years) was subsequently calculated using the (234)U/(238)Pu chronometer. HR-ICP-OES results were crossed-validated through sector field inductively coupled plasma mass spectrometry (SF-ICPMS) analysis of the (234)U/(238)Pu amount ratio of all samples applying isotope dilution combined with chromatographic separation of U and Pu. Available information on the assumed ages of the analyzed samples was consistent with the ages obtained via the HR-ICP-OES approach. Being based on a different physical detection principle, HR-ICP-OES provides an alternative strategy to the well-established mass spectrometric approach and thus effectively adds to the quality assurance of (234)U/(238)Pu age dates.

Direct electrokinetic injection of inorganic cations from whole fruits and vegetables for capillary electrophoresis analysis

A novel approach for the direct injection from plant tissues without any sample pre-treatment has been developed by simply placing a small piece of the tissue into a capillary electrophoresis vial followed by application of a voltage for electrokinetic injection. Separations of sodium, potassium, calcium and magnesium were achieved using a BGE comprising 10mM imidazole and 2.5mM 18-crown-6-ether at pH 4.5. The addition of 2% (m/v) hydroxypropylmethyl cellulose to the separation buffer allowed for precise and accurate electrokinetic injection of ions from the plant material by halting the movement of tissue fluid into the capillary. This method provides both qualitative and quantitative data of inorganic cations, with quantitation in zucchini, mushroom and apple samples in agreement with Sector Field Inductively Coupled Plasma Mass Spectrometric analysis (r2=0.98, n=9). This method provides a new way for rapid, quantitative analysis by eliminating sample preparation procedures, and has great potential for a range of applications in plant science and food chemistry.

Determination of precise ¹³⁵Cs/¹³⁷Cs ratio in environmental samples using sector field inductively coupled plasma mass spectrometry.

Recent advances in sector field inductively coupled plasma mass spectrometry (ICP-SFMS) have led to significant sensitivity enhancements that expand the range of radionuclides measurable by ICP-MS. The increasing capability and performance of modern ICP-MS now allows analysis of medium-lived radionuclides previously undertaken using radiometric methods. A new generation ICP-SFMS was configured to achieve sensitivities up to 80,000 counts per second for a 1 ng/L (133)Cs solution, providing a detection limit of 1 pg/L. To extend this approach to environmental samples it has been necessary to develop an effective chemical separation scheme using ultrapure reagents. A procedure incorporating digestion, chemical separation and quantification by ICP-SFMS is presented for detection of the significant fission product radionuclides of cesium ((135)Cs and (137)Cs) at concentrations found in environmental and low level nuclear waste samples. This in turn enables measurement of the (135)Cs/(137)Cs ratio, which varies with the source of nuclear contamination, and can therefore provide a powerful dating and forensic tool compared to radiometric detection of (137)Cs alone. A detection limit in sediment samples of 0.05 ng/kg has been achieved for (135)Cs and (137)Cs, corresponding to 2.0 × 10(-3) and 160 mBq/kg, respectively. The critical issue is ensuring removal of barium to eliminate isobaric interferences arising from (135)Ba and (137)Ba. The ability to reliably measure (135)Cs/(137)Cs using a high specification laboratory ICP-SFMS now enables characterization of waste materials destined for nuclear waste repositories as well as extending options in environmental geochemical and nuclear forensics studies.

LA-ICP-MS for Pu source identification at Mayak PA, the Urals, Russia

Information on Pu in environmental samples is traditionally based on the determination of the (240+239)Pu activity via Alpha Spectrometry (AS). A large number of alpha spectrometry sources (planchettes) containing radiochemically separated Pu are therefore stored worldwide and are available for further analyses. These archive samples represent a resource from which valuable information on isotopic composition of alpha emitters including Pu can be obtained. The relative abundances of Pu isotopes can be used to trace specific Pu sources and characterize the relative contributions of different Pu sources in a sample. Thus, in addition to the total (239+240)Pu activity, determination of the (240)Pu/(239)Pu ratio can provide valuable information on the nature of the Pu emitting sources. The Pu isotopic ratios can be determined by mass spectrometry techniques such as Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICPMS) or Accelerator Mass Spectrometry (AMS) that require dissolution and complete destruction of the material deposited on the planchettes. In this study Laser Ablation (LA)-quadrupole-ICP-MS has been employed for the analysis of (239)Pu/(240)Pu ratios from alpha-planchettes prepared from samples originating from the Mayak PA nuclear facility, Russia. The results are compared with data from AMS and show that the (240)Pu/(239)Pu ratios obtained by LA-ICP-MS can be utilized to distinguish weapons-grade Pu from civil reprocessing sources. Moreover, isotope ratio mapping can also be performed across the planchettes, allowing e.g. the visualization of possible inhomogeneities in the Pu-isotope distribution on their surface. Thus, this solid sample technique can be applied to extract additional information from existing archives of samples.

Simultaneous Determination of Trace Elements in Hepatocellular Carcinoma Tissue by Sector Field Inductively Coupled Plasma Mass Spectrometry

An analytical method using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) for rapid simultaneous determination of Na, Mg, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Sr, Mo, and Cd elements in hepatocellular carcinoma (HCC) tissue is reported. The sample was dissolved in HNO3 and H2O2 by microwave digestion and then the aforementioned 15 elements in the solution were analyzed directly by SF-ICP-MS. Most of the spectral interferences were avoided by measuring in medium resolution mode (MRM, M/▵M = 4400) and high resolution mode (HRM, M/ΔM = 8000). Correction for matrix effects was made using Sc and Rh as internal standards. The optimum conditions for the determination were tested and discussed. The results showed that SF-ICP-MS is a useful tool for simultaneous determination of multi-elements in HCC tissue and could be widely used in other biological samples analysis.

Measurement of Sulfur Isotopic Composition by Sector Field Inductively Coupled Plasma Mass Spectrometry

A precise method was developed for the determination of sulfur isotopic composition by sector field inductively coupled plasma mass spectrometry(SF-ICP-MS) under medium resolution mode(m/Δm=4000).To get the best accurate and precise 34S/32S ratio,multiple parameters were optimized and evaluated systematically,including the ion source,ion optical system,data acquisition parameters(i.e.scan time,scan numbers and integration window) and the effect of sulfur concentration.The instrumental mass discrimination was corrected using standard-sample bracketing.The δ34SV-CDT of sulfur isotopic reference materials GBW04414 and GBW04415 was measured in different days,the measurement values were -0.01‰±0.31‰ and 22.15‰±0.42‰,respectively.The results showed that this method had a high accuracy(error ±0.06‰) and good precision(repeatability ±0.5‰,n=10) in the determination of sulfur isotopic composition.Meanwhile,the proposed procedure was adopted to determine sulfur isotopic composition in some natural water samples(bottled mineral water,rain water and river water),the measurement precision was±0.19‰ to±0.58‰,similar to that of the isotopic reference materials.The proposed method was suitable for the determining the sulfur isotopic composition of natural water samples precisely.

Identification of Gunshot Residues in Fabric Targets Using Sector Field Inductively Coupled Plasma Mass Spectrometry Technique and Ternary Graphs*

During criminal investigations involving firearms, the detection of gunshot residues (GSRs) is one of the most important evidences. In the present study, a new method to identify trace evidences of GSRs, deposited around the bullet entrance hole, in different types of fabrics used as targets, is described. The experiments were carried out using a 0.38-inch caliber revolver, and 9-mm and 0.40-inch caliber pistols. Testimonies of 2.25 cm(2) of the fabrics were cut around the bullet entrance and digested with 10% nitric acid. Antimony, barium, and lead were analyzed in the remaining solution using a sector field inductively coupled plasma mass spectrometer. The concentrations of the elements were detected at levels up to few microgram per square centimeter. The use of ternary graphics allowed us to identify specific patterns of distribution for blank samples and the clear distinction between the revolver and pistols used.

The X-Ray and SF-ICP-MS Analysis of Content and Release of Allergenic Metals from Body Piercing

Metallic piercing which have lack of resistance to sweat corrosion might be able to release metallic ions in the local tissue producing adverse effects in the human body, including allergic contact dermatitis (ACD). The aim of this study was double: 1) the metallic characterization of piercings and 2) the release of metals (Al, Co, Cr, Cu, Fe, Ir, Mn, Ni, Pd, Pt, Rh, Ti, V and Zn) in artificial sweat to simulate conditions of use. Stainless steel and titanium piercings were sam- pled, and both the official and non official markets were checked. The X-ray microanalysis by Energy-Dispersion Spec- trometry and the Sector Field Inductively Coupled Plasma Mass Spectrometry were the techniques of election for metallic characterization and leaching analysis. The piercings analyzed were alloys of Fe/Cr/Ni or Fe/Mn/Cr. The coloured pierc- ings had a layer of Ti varying from 0.3 to 0.5 μm above the steel core and an external C stratum (0.04 μm). The titanium piercing was pure Ti. Piercings sampled from the official market released less than 0.05 μg/cm 2 /week of metal and thus, most likely, they are allergologically safe. Piercing purchased from the non official market were more susceptible to sweat corrosion promoting the release of considerable amounts of Cr (2.78 μg/cm 2 /week), Fe (26.95μg/cm 2 /week), Mn (51.15 μg/cm 2 /week) and Ni (0.157 μg/cm 2 /week). Iridium, Pd, Pt and Rh were not leached by any of the analyzed piercings.

SF-ICP-MS Analysis of Palladium in Fluids of Patients Sensitized to Metal-Based Dental Restorations

Palladium (Pd) belongs to the platinum group elements and its use has more than doubled in the past ten years. Encouraged by positive patch test results in some patients suffering from oral syndromes, Pd was included in the routine patch testing for contact dermatitis. In the present study, differences in the trend of sensitization to Pd in a contact derma- titis clinic population between 1996 and 2006 were evaluated. Since many in vitro studies have confirmed the corrosion of dental alloys and indicated that metal components are released in the oral cavity, Pd content was examined in leaching so- lutions from dental prostheses and in samples of saliva, serum and urine of subjects with adverse reaction to dental pros- theses. Measurements were performed by means of Sector Field Inductively Coupled Plasma-Mass Spectrometry (SF- ICP-MS). Results showed that the frequency of mono-reactions to Pd are increased from 1996 (0.11%) to 2006 (1.6%), suggesting that this metal is becoming a new potential allergen. The mean values of Pd levels detected in urine were higher than those found in saliva and in serum. All biological samples collected from patients showed significantly higher levels of Pd than controls (saliva, 255 ng/L vs 11; serum, 60 vs 15; urine, 580 vs 20). Moreover, after removal of the pros- theses a consistent reduction of Pd content in fluids was observed.

Environmental and biological monitoring of iridium in the city of Rome

The use of iridium in the latest catalytic converters to further reduce nitrogen oxide emission in the exhaust of lean-burn engines could result in increased atmospheric levels of this element in high-density vehicle traffic areas. The objective of this study is to assess environmental Ir pollution and its urinary levels in workers and an urban control group. Environmental monitoring inside a tram consisted in air samplings of total suspended particles (TSP), PM 10 and PM 2.5 carried out during November 2005. Urinary Ir levels were evaluated in 64 municipal tram drivers and in 58 administrative employees as controls. Quantification of Ir in air samples and urine was performed by means of Sector Field Inductively Coupled Plasma Mass Spectrometry. Means ± standard deviation of Ir levels in TSP, in PM 10 and PM 2.5 fractions were 1.43 ± 1.66, 0.44 ± 0.27 and 0.36 ± 0.19 pg m −3, respectively. No statistically significant differences were observed among urinary Ir values in the exposed subjects and control group. The Ir levels in Rome air are still sufficiently low, even if the increased use of new Ir-based catalysts could be of some concern in the near future. The results of our study are of interest as they are a first attempt to explore airborne levels and urinary concentrations of Ir in an urban context at medium-high density of vehicle traffic. Particular attention should be given to the fact that Ir was found in the finest dust particles as the effects of fine particles containing Ir have not yet been studied.

A pilot study on the content and the release of Ni and other allergenic metals from cheap earrings available on the Italian market

The capability of alloys used in cheap jewellery to release metal ions on contact with the skin causing allergic contact dermatitis (ACD) is generally acknowledged. To reduce the diffusion of the Ni-induced ACD the Council Directive 94/27/EC [Council Directive 94/27/EC of 30 June 1994. Official Journal L 188, 22/07/1994, 1.] limited the total Ni content in alloys and its release rate in artificial sweat. In this work, three different aspects were explored: i) the frequency of skin sensitization to Ni-containing earrings in patients before and after the introduction of the Directive's limit; ii) metal composition of alloys by X-ray analysis; iii) metal leaching in artificial sweat followed by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) quantification. Well-known allergenic metals, as Ni, Cr and Co, and possible emergent allergens, as Al, Ag, Au, Cd, Cu, Fe, Ir, Mn, Pb, Pd, Pt, Rh, Sn, V and Zn, were studied. Results showed that the frequency of allergy due to earrings did not decrease after the introduction of the Ni limit: in 1994 and in 2005 patients positive to Ni patch tests were 54.3% and 53.5%, respectively. The earring components analyzed were Fe-based or alloys of Cu/Zn or Fe/Cr/Ni, plated with a thin film of precious metal (Ag, Au) which, in several cases, was combined with a Ni layer beneath. Five out of 10 items were not in compliance with the Ni Directive 94/27/EC having a total Ni content > 0.05%. In three cases the release of Ni concentrations was higher than the safe sensitizing limit given by the above mentioned Regulation ( i.e., < 0.5 μg/cm 2/week). The release of Cu and Zn was very variable among the different pieces (Cu: 0.134–30.9 μg/cm 2/week; Zn: 0.141–160 μg/cm 2/week); two objects released high amounts of Fe (358 and 586 μg/cm 2/week) and one released considerable Mn (21 μg/cm 2/week). Lead was released from 70% of the objects, while Ag, Al, Cd, Co, Cr and Sn from ca. 30% of the items and concentrations of these elements were well below 0.5 μg/cm 2/week. Vanadium was released by only one item whereas Au, Ir, Pd, Pt and Rh were never leached.

Determination of Cd and Pb in Honey by SF‐ICP‐MS: Validation Figures and Uncertainty of Results

A method based on microwave‐assisted acid digestion of honey and quantification of Cd and Pb by Sector Field Inductively Coupled Plasma Mass Spectrometry was in‐house validated and the combined uncertainty was estimated according to the Eurachem/Citac Guide. Limits of detection and quantification were 0.07 and 0.20 ng g−1 for Cd, and 0.70 and 2.10 ng g−1 for Pb; recovery was 103.9% for Cd and 98.5% for Pb; repeatability was 10.7% for Cd and 18.5% for Pb; within‐laboratory reproducibility was 15.2% for Cd and 21.4% for Pb. Relative combined uncertainty in honey was 15% for Cd and 22% for Pb, with the main contribution coming from the within‐laboratory reproducibility. The method showed robustness when subjected to different working conditions and when applied to various Italian honeys. Cadmium content ranged 0.2–1.37 ng g−1 and Pb 4.6–30.5 ng g−1 in flower honeys, while the highest concentrations were presented by honeydew honeys.