Determination Of Metallic Impurities Research Articles

Determination of Metallic Impurities by ICP-MS Technique in Eyeshadows Purchased in Poland. Part I.

Eye shadows, which are products willingly and frequently used by women and even children, have been reported in literature to contain toxic metals. In this work, a total of 94 eye shadows samples available on the Polish market were collected. Eye shadow products have been selected in order to include several parameters important from the point of view of the typical consumer such as: product type (mat/pearl), consumer group (for adults and children), price range (very cheap, medium price, expensive and very expensive), color (twelve different colors were tested), manufacturer (eight brands were investigated) or country of production (four countries were included). The concentration of selected metals (Ag, Ba, Bi, Cd, Pb, Sr, Tl) was determined by ICP-MS technique after the sample extraction with a mixture of nitric acid and hydrogen peroxide in a microwave closed system. For Ag, Cd and Tl, some results were below the established limit of quantification for the employed technique. The presence of strontium, barium, lead and bismuth was confirmed in all studied samples. The obtained results for analyzed elements were, in general, quite comparable with the data reported by other authors. A small number of samples exceeding the permissible values (two samples were beyond the limit value for Cd of 0.5 mg/kg and one exceed the acceptable concentration for Pb of 10 mg/kg) also proves a relatively good condition of the Polish cosmetics market and suggests insubstantial risk for the potential consumers. The results gathered for some of the eye shadows intended for children turned out to be alarmingly high, in particular for elements such as Cd. The highest concentration of Cd reached almost 4 mg/kg, while of Pb amounted to 16 mg/kg. The presence of the statistically significant differences was confirmed for all included parameters with an exception of the color of the eye shadow. Considering the results acquired only for Cd and Pb with respect to the country of origin, the least contaminated cosmetics by metallic impurities seem to be the one produced in Canada, while the ones presenting the highest health risk among all studied eye shadows are make-up cosmetics originating from Poland and Italy. Multivariate analysis of a large data set using CA methods and PCA provided valuable information on dependencies between variables and objects.

Determination of Metallic Impurities in Carbon Nanotubes by Glow Discharge Mass Spectrometry.

A method for the rapid assessment of metallic impurities in carbon nanotubes (CNTs) by pin-cell source geometry glow discharge mass spectrometry (GDMS) is presented. Pins were prepared by pressing CNT powder onto an indium substrate. GDMS analysis was performed using high-carbon-content nanotube and coal-certified reference materials for calibration purposes. This approach enables the calibrated measurement of 41 elemental impurities in CNTs. The method was validated by the analysis of NIST SRM 2483 single-wall CNTs (raw soot) with good agreement with the certified values. The proposed measurement approach could also be applied not only for CNTs but also for the assessment of precursor materials used in the synthesis of CNTs and for quality control during the entire manufacturing process. The ability to assess the presence of all metallic impurities in a simple, reliable, high-throughput manner will allow the industry to real-time monitor any changes in the product process, access its toxicity, and environmental impact. As sample preparation is maintained to a minimum, this allows the determination of metallic impurities at concentration levels that are usually not attainable by most techniques.

Comparative Analysis of Gearboxes Wear in Excavators and Mining Trucks

The primary task of all enterprises in mining industry is to increase the durability and reliability of the mining complex. These very indicators provide nonstop minerals mining, and as a result, productivity increases. Indicators maintaining at high level can be achieved by different ways, but the most effective method is repair-in-place diagnosis of the actual technical condition of the main units and assemblies of equipment, as it is less costly and the most informative. To identify gear malfunctions, the physical and chemical analysis of the used oil is used to determine metallic impurities. A comparative analysis of wear products accumulation in rotary gears of mining excavators and gearboxes of the motor-wheel of dump trucks revealed the similarity of mathematical models for the determination of metallic impurities in used oil. The “universal” mathematical model is given in the paper; it allows to determine the actual technical condition of gearboxes for various equipment with a few assumptions. Moreover, the model takes into account various indicators of the environment, used oil, as well as the operating parameters of the equipment.

Determination of Metal Impurities in Carbon Nanotubes Sampled Using Surface Wipes.

Residual metal impurities in carbon nanotubes (CNTs) provide a means to distinguish CNT from non-CNT sources of elemental carbon in environmental samples. A practical and cost-effective analytical approach is needed to support routine surface monitoring of CNT metal tracers using wipe sampling. Wipe sampling for CNT metal tracers is considered a qualitative indicator of the presence of CNTs, not a quantitative exposure metric. In this study, two digestion approaches (microwave-assisted nitric acid/H2O2 digestion and ultrasonic nitric/HF acid digestion) in conjunction with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) determination were evaluated for their ability to extract metal impurities from CNT particles captured on wipe substrates. Aliquots of different carbon nanotubes (including NIST 2483 single-wall CNT) with and without GhostWipes™ (ASTM E-1792 compliant) were used to compare the performance of the digestion methods. The microwave digestion method accommodated the bulky wipe sample and also eliminated potential ICP-MS signal interferences related to incomplete digestion. Although quantitative recoveries requiring lengthy multistep digestion protocols may be necessary in other applications, the near-total recoveries achieved in the present study for CNT catalyst elements were adequate for identifying surface contamination of CNTs in the workplace using wipe sampling.

A technique for determination of metallic impurities in Al2O3 matrix by EDXRF

The applicability of energy dispersive X-ray fluorescence spectrometry as an analytical technique for the determination of a few metallic impurities such as Ca, Cr, Cu, Fe, Mn, Pb, and Zn in alumina (Al2O3) matrix was investigated. A series of Al2O3 standards containing the elements of interest in the range 10–1000 ppm was prepared and the spectrometer conditions were optimized to obtain calibration plots for the various analytes that could be further used for the analysis of actual samples. The present method serves as an alternative to currently used AES method for analytes expected in the concentration range 50–1000 ppm.

Synthesis, quality control and determination of metallic impurities in 18F-fludeoxyglucose production process

AimThe aim of this study was to synthesize 18FDG in some consecutive runs and check the quality of manufactured radiopharmaceuticals and to determine the distribution of metallic impurities in the synthesis process. BackgroundFor radiopharmaceuticals the general requirements are listed in European Pharmacopeia and these parameters have to be checked before application for human use. Materials and methodsStandard methods for the determination of basic characteristics of radiopharmaceuticals were used. Additionally, high resolution γ spectrometry was used for the assessment of nuclidic purity and inductively coupled plasma with mass spectrometry to evaluate metallic content. ResultsResults showed sources and distribution of metallic and radiometallic impurities in the production process. Main part is trapped in the initial separation column of the synthesis unit and is not distributed to the final product in significant amounts. ConclusionsProduced 18FDG filled requirements of Ph.Eur. and the content of radionuclidic and metallic impurities was in the acceptable range.

Direct and simultaneous determination of metal impurities in catalysts based on platinum group elements

Abstract Production of new catalysts requires effective analytical quality control. The study of trace element composition of heterogeneous catalysts, based on C+PdO, using atomic emission spectrometry (AES) was carried out. A new method for the direct solid-state analysis by means of AES with direct current arc discharge was developed. On the basis of the qualitative analysis of elements, Al, Fe, Ni, Si and Ti have been identified, and for these elements, the quantitative method of determination has been developed. Optimization of excitation parameters and validation of the analytical method are presented. Calibration samples of the following composition were prepared: graphite powder (as a matrix), 3% of PdO and increasing contents of determined element oxides (spectrally pure). Calibrations were calculated by means of the least squares method. Working range for element impurities was from 1% to 0.0003%, and the limits of quantification — LOQ, (10-σ criterion) varied in the range from 0.002% (Ti) to 0.0038% (Si). For the control of active component, palladium was calibrated (working range — 0.01%–10.00%; LOQ −0.027%). The developed method can be used, also, for the elemental determinations of the other carbon based catalysts with the different active components (of platinum group elements).

Determination of metal impurities in advanced lead zirconate titanate ceramics by axial view mode inductively coupled plasma optical emission spectrometry

An inductively coupled plasma optical emission spectrometry quantification method for the determination of Al, Ca, Cr Cu, Fe, Mn, Mg, Ni, Zn, Ba, K, In and Co in lead zirconate-titanate (PZT) ceramics, modified with strontium and chromium, was developed. Total digestion of ceramics was achieved with a HNO3, H2O2 and HF (ac) mixture by using a microwave furnace. The sensitivity of the net signal intensity respect to radiofrequency power (P) and nebulizer argon flow (FN) variations was strongly dependent of the total excitation energy of line (TEE). For lines with TEE near metastable atoms and ions of argon, an increment of the sensitivities to P and FN variation was observed. At robust plasma conditions the matrix effect was reduced for all matrices and analytes considered. The precision of analysis ranged from 3 to 13%, whereas the analytes recoveries in the spiked samples varied, mostly, from 90 to 110%. The detection limits of studied elements were from 0.004 to 10mgkg−1.

Determination of metal impurities in carbon nanotubes by direct solid sampling electrothermal atomic absorption spectrometry

Metal impurities (Al, Cd, Co, Cr, Cu, Mg, Mn and Pb) were determined in carbon nanotubes (CNTs) by direct solid sampling electrothermal atomic absorption spectrometry (DSS-ET AAS, deuterium lamp background corrector). Parameters as pyrolysis and atomization temperatures, use of Pd as chemical modifier, feasibility of calibration using aqueous standard solutions and maximum sample mass were investigated. Results obtained by the proposed method were compared with those obtained by neutron activation analysis (NAA) and also by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP OES) after high-pressure microwave assisted wet digestion and microwave-induced combustion methods. No significant differences were observed between the results obtained by DSS-ET AAS, ICP-MS and ICP OES after both digestion methods and also by NAA. Calibration was performed using aqueous standards. Background signals were always lower than 0.02 (peak height) and no chemical modifier was used. The proposed method allowed the determination of all elements in CNTs with lower limits of detection in comparison with other techniques.

Application of energy dispersive X-ray fluorescence for the determination of metallic impurities in ThO2

Energy dispersive X-ray fluorescence (EDXRF) spectrometric methods have been developed for the determination of some common metallic impurities in ThO2 matrix. A series of ThO2 standards containing the analyte impurities in the range 10–100 (or 100–500) μg/g was prepared synthetically. The spectrometer conditions were optimized to obtain calibration plots for the various analytes. The accuracy and precision of the developed methodology for regular assay of ThO2 was evaluated by analyzing three synthetic samples. Further three secondary ThO2 standards were analyzed by EDRXF to check the developed methods. The determined concentrations of Ca, Cr, Fe, Ni and Cu were in good agreement with the certified values of the secondary standards.

Determination of metallic impurities in U 3O 8 using energy dispersive X-ray fluorescence spectrometry

In order to examine the capability of energy dispersive X-ray fluorescence spectrometry for the determination of some common metallic impurities in nuclear grade U 3O 8 matrix, a series of synthetic U 3O 8 standards, containing impurities such as Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni ,V, W and Zn in the concentration range, 100–1000 μg/g, were prepared. Using these standards, calibration curves were set up for different elements after optimizing the spectrometer parameters. Two synthetic samples and five reference standards obtained through an inter-laboratory comparison exercise within analytical laboratories of Department of Atomic Energy, India were analyzed to evaluate the performance of the newly developed analytical methods. The estimates for most of the analytes were in good agreement with the added amounts. The method is fast, since it requires no chemical treatment. The method has good precision for the analytes determined.

Determination of metal impurities in pure hydroxides and salts by inductively coupled plasma optical emission spectrometry

A simple analytical method sufficient for the determination of Na, K, Ca, Mg, Al, B, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sr, V and Zn at mg kg −1 levels in pure NaOH, KOH, NaCl and KCl using the optical emission spectrometry was developed. The results of direct determination with multi-elemental aqueous standards were compared with them obtained by the internal standardisation, by the standard addition methods and with the maximal allowable contents of above-mentioned elements in pure chemicals. The method was shown to be very sensitive and exhibits following limits of detection: Na 0.90, K 3.0, Ca 0.064, Mg 0.026, Al 0.43, B 0.13, Ba 0.015, Cd 0.023, Co 0.056, Cr 0.041, Cu 0.063, Fe 0.060, Li 0.017, Mn 0.035, Mo 0.19, Ni 0.055, Pb 0.39, Sr 0.030, V 0.065 and Zn 0.043 (all in mg kg −1). The method presents a satisfactory precision (relative standard deviation 4–11%), high analytical recoveries, linear responses of at least four orders of magnitude, accuracy and low contamination susceptibility.

Determination of metal impurities in ultrapure CaCl2 and MgCl2 by ICP OES

An effective, rapid and simple analytical method for the determination of Na, K, Ca, Mg, Cd, Pb, Ba, Fe, Mn, Sr, Zr, Cu, Zn and Al at mg kg−1 levels in the ultrapure salts MgCl2 and CaCl2 using optical emission spectrometry was developed. Optimisation of the operation conditions was performed with real samples of ultrapure MgCl2 and CaCl2. The results of the determination with multi-elemental water standards were compared to the internal standardisation, the standard addition method, and the maximum allowable content of the above mentioned elements in pure chemicals. The method was shown to be very sensitive with the following limits of detection: Na 1.01, K 3.12, Ca 0.263, Mg 0.275, Cd 0.0832, Pb 0.482, Ba 0.0153, Fe 0.0528, Mn 0.0473, Sr 0.0203, Zr 0.638, Cu 0.0732, Zn 0.0686 and Al 0.459 (all in mg kg−1). The method exhibited satisfactory precision, high analytical recoveries, linear responses of an accuracy of at least 4 orders of magnitude and low contamination susceptibility.

Determination of metal impurities in titanium dioxide using slurry sample introduction by axial viewing inductively coupled plasma optical emission spectrometry

A slurry sample introduction technique for the analysis of TiO2 powders by axial viewing ICP-OES is reported. Relationships between stable slurries and the conditions, such as particle size, pH, dispersant and its amount, were experimentally investigated. Slurries were prepared by mixing the TiO2 powder with the dispersant poly(acrylate amine) (NH4PAA) and agitation in an ultrasonic bath to ensure good dispersion. The pH of the medium and amount of dispersant has been optimized. Impurities in TiO2 were determined by an axial viewing ICP-OES spectrometer. As representatives, a Standard Reference Material 154 b of µm particle size TiO2 and a nm particle size TiO2 were selected and determined for micro and trace impurities. Analytical results obtained via slurry sample introduction were compared with those via nebulization of aqueous solutions prepared by acid digestion and fusion digestion. The determined results by slurry introduction were in good accordance with the stated values, which verified that the calibration curves could be established by aqueous standards.

Slurry sampling fluorination assisted electrothermal vaporization-inductively coupled plasma-atomic emission spectrometry for the direct determination of metal impurities in aluminium oxide ceramic powders.

A new analytical procedure for the direct determination of metal impurities (Cr, Cu, Fe and V) in aluminium oxide ceramic powders by slurry sampling fluorination assisted electrothermal vaporization-inductively coupled plasma-atomic emission spectrometry (ETV-ICP-AES) is reported. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization of impurity elements in aluminium oxide ceramic powders from the graphite tube. A vaporization stage with a long ramp time and a short hold time provided the possibility of temporal analyte-matrix separation. The experimental results indicated that a 10 microL 1% m/v slurry of aluminium oxide could be destroyed and vaporized completely with 600 micrograms PTFE under the selected conditions. Two aluminium oxide ceramic powder samples were used without any additional pretreatment. Analytical results obtained by using standard addition method with aqueous standard solution were checked by comparison of the results with pneumatic nebulization (PN)-ICP-AES based on the wet-chemical decomposition and analyte-matrix separation. The limits of detection (LODs) between 0.30 microgram g-1 (Fe) and 0.08 microgram g-1 (Cu) were achieved, and, the repeatability of measurements was mainly better than 10%.

Determination of metallic impurities in high-purity type IIa diamond grown by high-pressure and high-temperature synthesis using neutron activation analysis

Metallic impurities in high-purity type IIa and conventional type Ib diamond single crystals grown by high-pressure and high-temperature (HPHT) synthesis were determined by neutron activation analysis using thermal neutrons. Metallic impurities of Fe, Co, Cr and other minor elements were detected in the high-purity type IIa diamond crystal. The typical quantities of these metallic impurities were a few ppb. The influence of these metallic impurities on the electrical properties of the type IIa diamond crystal was practically negligible compared with nitrogen and boron impurities behaving as a donor and an acceptor, respectively. In addition to the impurities detected in the type IIa diamond crystal, Ni impurities of several hundreds of ppb were detected in conventional type Ib diamond crystals. A difference in molten metal solvents used in the synthesis of each diamond crystal resulted in the difference in metallic impurities.

Determination of Metal Impurities in Tantalum Diboride after Acid Dissolution by Inductively Coupled Plasma Atomic Emission Spectrometry

Determination of Metal Impurities in Tantalum Diboride after Acid Dissolution by Inductively Coupled Plasma Atomic Emission Spectrometry

Direct determination of metal concentrations in freshwater algae by total reflection X-ray fluorescence spectrometry

A direct TXRF method for the determination of metal impurities by applying three different freshwater algae, viz., Chlorella keslerii, Synehococcus sp. and Cylindrospermopsis raciborskii, was developed. The applicability of the slurry sampling technique was confirmed by comparing the analytical results obtained with those obtained by total digestion of the algae. The concentration data showed an acceptable agreement for Cu, Fe, Mn and Zn. The calculated accumulation factors for the metals detected were highest for Chlorella keslerii.

Determination of metal impurities in sulfamic acid by isotope dilution electrothermal vaporization inductively coupled plasma mass spectrometry

Metal impurities present at sub-ng g–1–ng g–1 levels in high-purity sulfamic acid reagents were determined by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) with sample introduction by electrothermal vaporization (ETV). Matrix constituents causing suppression and enhancement of analyte signals were removed from the sample introduction system at the pyrolysis stage before ETV-ICP-MS measurement. As the ETV device, both tungsten and graphite furnaces were employed. In graphite furnace ETV-ICP-MS, it was necessary to use a chemical modifier in order to enhance the signal sensitivity and to obtain a linear calibration graph. In tungsten furnace ETV-ICP-MS, a linear relationship between the analyte mass and the signal was achieved without the use of a modifier but the stability of the isotope ratio measurement was slightly poorer than that in graphite furnace ETV-ICP-MS. The relative standard deviations obtained by ETV-ICP-MS using both furnaces were 6–30%. The analytical results for two types of sulfamic acid reagent obtained by tungsten furnace ETV-ICP-MS agreed with those obtained by graphite furnace ETV-ICP-MS.

Electrothermal vaporization–inductively coupled plasma mass spectrometry for determination of metal impurities in slurries of aluminium oxide

A new analytical procedure for the direct determination of metal impurities in aluminium oxide by ultrasonic slurry sampling–electrothermal vaporization–inductively coupled plasma mass spectrometry (ETV–ICP-MS) is reported. The elements studied include Cr, Cu, Ga, Fe, Mg, Mn, Na, V and Zn. Two samples of fine alumina powder (including the certified reference material NIST SRM 699) were used in this study without any additional pre-treatment. Analytical results of the external calibration using aqueous standards, the external calibration using matched matrix standards and the standard additions method are presented and compared. The most appropriate (average accuracy of 97±5.5% for sample NIST SRM 699) was the standard additions procedure of calibration. An acceptable agreement was found between the results of the slurry sampling procedure and the certified or reference values, and the repeatability of measurements was always better than 13.6%. Some other analytical figures-of-merit,e.g., limits of detection, are also presented. The absolute limits of detection (for the analysis of 15 µl samples) ranged from 0.8 to 8.3 pg. The speed and multi-element analytical potential of this technique seem to be very advantageous.