Optimization of slurry nebulization inductively-coupled plasma atomic emission spectrometry for the analysis of ZrO2-powder

The optimization and use of ICP-AES with slurry nebulization for the direct analysis of ZrO₂-powder is described. The powder samples are dispersed in water, acidified to pH 2 and the slurry is fed into a Babington nebulizer. The effects of grain size, pH of the suspending medium and standing time on the stability of the slurry are discussed. For the optimization of the ICP operating conditions, a simplex technique is applied and for this purpose three types of objective functions were examined. Identical behaviour of slurries and solutions with the same matrix concentrations in the ICP-AES is achieved for powders with particle sizes lower than 10 m; in the latter case calibration can be performed by standard addition with aqueous solutions. The detection limits for Al, B, Ca, Cu, Fe, Mg, Mn, Na, Ti, V. Y are 0.03 g/g to 10 g/g and the standard deviation is generally lower than 10%. Six commercially available ZrO₂ powders are analyzed by slurry nebulization ICP-AES and the results were found to agree well with those obtained by ICP-AES after chemical decomposition of the samples.On leave from Department of Analytical Chemistry, Technical University, PL-00-664 Warsaw, Poland     

Inductively-coupled plasma atomic emission spectrometric determination of boron based on generation of methyl borate

Boron is converted to methyl borate, distilled and condensed, and selectively volatilized at 50°C into the plasma without interference from methanol, which quenches the plasma. The 3σ detection limit is 40 ng ml^?1 boron, the calibration graph is linear up to 10 μg ml^?1 and the r.s.d. 3.0% for 2.0 μg ml^?1 (n = 10). Boron is determined in plant-tissue and steel standards.     

Extractive chromatographic separation and inductively coupled plasma atomic emission spectrometric determination of trace impurities in high purity europium oxide

An easily applicable separation method has been developed for the accurate and simultaneous determination of trace amounts of Al, Ca, Co, Cr, Cu, Mg, Mn, Ni, Pb and Zn in high purity europium oxide by inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with extraction chromatography. Spectral interferences and europium matrix effects were examined. The chromatographic separation procedure was carried out with a di-(2-ethylhexyl) phosphoric acid (HDEHP)-Levextrel resin as the stationary phase, which retained the matrix europium, and dilute nitric acid as the mobile phase, which eluted the analyte of interest. The effect of nitric acid concentration on the adsorption of europium and the analyte ions on the resin, the eluting behaviour of these elements on the chromatographic column, and the capacity of the resin for europium oxide were investigated. The quantitative limits for determination (10 sigma), based on a 0.5-g amount of europium oxide, are between 0.36 microg/g for Mn and 6.4 microg/g for Pb. The method was applied to two spiked samples and a high purity europium oxide certified reference material. Results were obtained for recoveries of 93.2-112% and precision of 4-13%, expressed as the relative standard deviation and excellent agreement with the certified value with a relative error of <4%.     

Matrix effect in the atomic emission determination of impurities in arsenic

Changes in the intensities of analytical lines due to impurities in the arsenic—graphite powder binary system were studied. It was found that these changes exhibited a complex nonlinear character. Factors responsible for the observed effect were examined.     

Preconcentration and determination of trace chromium(III) by flow injection/inductively-coupled plasma/atomic emission spectrometry

A manifold incorporation an activated alumina (basic form) minicolumn is used to preconcentrate chromium(III), which is then eluted with 2 M nitric acid for detection. Calibration is linear up to 1000 μg l^? Cr, and the limit of detection for a 10-ml sample is 0.05 μg l^?1. The determination of chromium(III) in human urine is discussed.     

Determination of trace amounts of sodium and lithium in zirconium dioxide (ZrO2) using liquid electrode plasma optical emission spectrometry

This paper describes a quantitative measurement of trace elements (Na, Li) in high purity zirconium dioxide powder using liquid electrode plasma optical emission spectrometry (LEP-OES). Conventionally, for such type of measurements, inductively coupled plasma optical emission spectrometry (ICP-OES) is frequently employed. The detection limits of elements in zirconium by ICP-OES are degraded due to the spectra interference between the trace elements and zirconium of the matrix, because zirconium is a line rich element in spectra obtained by ICP-OES. LEP-OES is an elemental analysis method developed by the authors. The measurement principle is simple, as follows. Sample solution is put into a narrow channel on a small cuvette and voltage pulse is applied from both ends of the channel. At the center of the channel which is made narrower, the voltage and current are concentrated there, and plasma is generated. From the emission of the plasma, the quantitative analysis of the elements in the solution is achieved. The LEP-OES has the property that the emission of zirconium is relatively weak, so that highly sensitive measurement of trace elements in zirconium matrix can be conducted without interference. Sample solution is prepared by dissolving high purity zirconium dioxide powder and trace amounts of Na or Li with sulfuric acid. The voltage dependence and the pulse width dependence of optical emission spectra are also investigated. With increase of the voltage or the pulse width, the ratio of emission intensities of Na to those of hydrogen increases. This suggests that the ratio of sensitivity of two elements is variable, that means the element selectivity is controllable to some extent by the measurement conditions in LEP-OES. In the case of Na and H, the ratio can be controlled from 7.4 to 21.6%. Finally, the detection limits (3S.D.) of the trace elements, Na and Li, in 4000 μg g⁻¹ zirconium dioxide aqueous solution are found to be 0.02 and 0.133 μg g⁻¹, respectively. These values correspond to 5 μg g⁻¹ for Na, 33.25 μg g⁻¹ for Li in original high purity zirconium dioxide powder. The correlation coefficient of calibration curve was 0.995 for Na, 0.985 for Li. Those are comparable to the literature values of detection limits using ICP-OES.     

无滤共沉淀富集-等离子体原子发射光谱法测定痕量稀土元素

以编结反应器 (KR)作为反应场所,用NH3～NH4NO3缓冲溶液在线沉淀、富集,电感耦合等离子体原子发射光谱法(ICP-AES)检测稀土元素,系统地研究了稀土元素在线沉淀及溶解的最佳条件.实验结果表明:在80 ℃时,稀土离子与pH 9.0的NH3～NH4NO3缓冲溶液在线混合后经2 m KR富集120 s,用1 mol/L HNO3以1.0 mL/min流速洗脱时富集效果最好,富集倍数可达52～76倍,进样频率为10/h.同时考察了共存离子的干扰及其消除方法.方法的稀土元素的检出限为0.07～1.23 μg/L,精密度RSD在1.7%～4.3%之间(n=6),线性范围2～10 μg/L.应用于标准样品中痕量稀土元素的测定,其测定值与标准值吻合.     

A capacitively coupled microwave plasma atomic emission spectrometer for the determination of trace metals in microsamples

A capacitively coupled microwave plasma operating at 450 to 850 W is used for atomic emission spectroscopy. The laboratory-constructed system contains a tungsten cup electrode capable of holding a volume of up to 30 μl. Microwaves are used to dry the sample, while at higher powers the plasma is ignited for sample vaporization and excitation. The entire analysis can be carried out in less than 5 min. A mixture of helium and hydrogen is used as the plasma gas. A spherical or cylindrical shaped plasma can be formed depending upon the gas flow rate and the microwave power selected. The effects of experimental parameters, such as gas flow rate, atomization power, electrode position and plasma shape are examined. Detection limits for Cd, Mg and Zn are in the low picogram range for a 10 μl sample; the relative standard deviation is less than 10%.     

Direct determination of trace rare earth elements in high purity Y2O3 using fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry with slurry sampling

A new method for the determination of trace amounts of 14 rare earth elements in high purity Y₂O₃ using fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry with slurry sampling was developed. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization of the analytes from graphite furnace. The main factors affecting analytical signals were investigated systematically. The interference of matrix could be minimized in the presence of PTFE. Under optimum conditions, the detection limits for rare earth elements were 0.032 ng∼2.52 ng and the relative standard deviations were in the range of 1.4% to 4.3%. The proposed method was applied to the direct analysis of high purity Y₂O₃ powder with satisfactory results. Received: 19 June 1999 / Revised: 10 December 1999 / Accepted: 16 December 1999     

Application of atomic absorption spectrometry and plasma emission spectrometry to the determination of trace elements in water

Microchimica Acta - The methodology and applicability of two methods for the serial determination of heavy metal traces in water samples is described. Their use within the project of the Deutsche...     

Direct determination of toxic trace metals in honey and sugars using inductively coupled plasma atomic emission spectrometry

A rapid method for the determination of Pb, Cd, Cu, Cr, Co, Ni, Mn and Zn in honey and sugars without prior digestion or ashing of the sample was developed, using inductively coupled plasma atomic emission spectrometry (ICP-AES). The critical instrumental parameters such as sample flow rate and radio frequency incident power were thoroughly optimized. The effect of matrix type and its concentration was also examined for glucose/fructose, sucrose and honey matrices. The sensitivity was investigated using calibration curves obtained in presence of the above matrices. The obtained recoveries for Cd, Cu, Cr, Co, Ni and Mn at the μg l⁻¹ level were satisfactory and practically independent of the matrix used for the calibration standards. The recoveries of Pb and Zn were less sufficient. Various commercial samples of honey, sugar, glucose and fructose were analyzed with respect to their toxic metal content. The method can be applied for routine analysis, quality and environmental pollution control purposes at the μg l⁻¹ level of concentration, after suitable dilution of the samples.     

Spectrographic determination of metallic impurities in PuO2

Summary An emission spectrographic method has been developed for the estimation of 22 metallic impurities in plutonium dioxide using carrier-distillation technique Silver chloride at 5% concentration in a charge of 100 mg has been used as the carrier. Mixed oxide standards containing 10% PuO₂ have been used for the analysis of matching composition of plutonium samples. Precision and accuracy determinations of the synthetic samples indicate 7–16% deviation for most of the elements. The work described includes analysis of reference samples and matrix effect studies. The method is suitable for the chemical quality control analysis of plutonium oxide to be used for Fast Breeder Test Reactor (FBTR) fuel.

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Spektralanalytische Bestimmung von metallischen Verunreinigungen in PuO₂

Zusammenfassung Mit dem Verfahren der Trägerdestillation können 22 Elemente in Plutoniumdioxid spektralanalytisch erfaßt werden. Als Träger dient 5% Silberchlorid in je 100 mg. Mischoxid-Standards mit 10% PuO₂ wurden verwendet. Bei der Untersuchung von Genauigkeit und Reproduzierbarkeit synthetischer Proben wurden für die meisten Elemente Abweichungen von 7–16% festgestellt. Matrixeinflüsse wurden ebenfalls untersucht sowie Analysenergebnisse für bestimmte Bezugsstandards mitgeteilt. Das Verfahren eignet sich für die Qualitätskontrolle von PuO₂-Brennstoffen für schnelle Brutreaktoren.

     

Spectral interferences in the determination of trace elements in environmental materials by inductively coupled plasma atomic emission spectrometry

This paper deals with spectral interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES) encountered with environmental materials. These samples normally contain high concentrations of aluminium, calcium, magnesium, iron, titanium, potassium and sodium. The investigations cover: (a) spectral data for Al, Ca, Mg, Fe, Ti, K and Na as interferents for 200 pm wide windows centred (±100 pm) around the prominent lines of As, B, Ba, Be, Cd, Cr, Cu, Hg, Mn, P, Pb, Sb, Se, Sn, Tl, U and Zn; (b) a data base of Q-values for line interference [Q_Ij(λ_a)] and Q-values for wing background interference [Q_Wj(Δλ_a)] for two values of the excitation temperature 6200 K and 7200 K. The lines free or negligibly influenced by line interference were selected for analyte determination. Q-values were used for calculation of correction factors under a spectral line without the measurement of a reference blank at the wavelength of the prominent analysis lines. The accuracy of ICP-AES with the Q-concept as a basic methodology is checked by the analysis of a certified reference material IAEA/Sediment SD-N-1/2/. The precision of the method is characterised by an RSD of 0.6–1.7%. Extraction of trace elements soluble in aqua regia was used as a decomposition method. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), a section of Spectrochimica Acta, Part B (SAB). The hardcopy text is accompanied by an electronic archive, stored on the SAE homepage at http://www.elsevier.nl/locate/sabe. The archive contains the tabular material of this article in electronic form.     

Determination of trace impurities in uranium, thorium and plutonium matrices by solvent extraction and inductively coupled plasma atomic emission spectrometry

Studies on the determination of trace metallic impurities in nuclear materials such as uranium, thorium and plutonium are described. The bulk of the matrix is separated by batch extraction from their nitric acid solutions using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC88-A). The final aqueous phase containing the metallic impurities is fed to a high-temperature source inductively coupled plasma and the analysis is carried out employing a computer-controlled multichannel direct-reading spectrometer. The studies also included the recovery of impurities at various acidities and spectral interferences of the above matrices over the analyte elements. Based on the above studies, methods were standardized for the determination of 19 elements, viz. Al, B, Be, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si, Zn, Ce, Dy, Eu, Gd and Sm, in U/Th/Pu solutions. The relative standard deviation for various elements is in the range 1-5%.     

Direct determination of trace amounts of sodium in water-soluble organic pharmaceuticals by microwave induced plasma atomic emission spectrometry

The direct determination of trace sodium by microwave induced plasma atomic emission spectrometry (MIP-AES) in water-soluble organic substances utilized in pharmaceutical preparations was developed. No decomposition of the organic constituents was required. Samples were dissolved with water and introduced to the plasma after ultrasonic nebulization without desolvation. A limit of detection (3sigma) of 0.91-3.0 ng ml(-1) was obtained under experimental conditions. The quantitative MIP-AES procedure involved the standard addition method. The sodium content determined in reference material NIST SRM 1568A Rice Flour agreed with the certified value (6.6+/-0.8 mug g(-1)). Physical and chemical interferences were investigated. It was found for the microwave plasma that it is possible to introduce organic substances solutions of concentration up to 5% without sensitivity losses. This direct technique is fast and sensitive and helps to reduce contamination connected with the sample preparation procedure.     

Determination of trace elements in bone by two-jet plasma atomic emission spectrometry

This paper describes an analytical method for trace element determination in bone tissues. The study of the influence of the bone matrix showed that the addition of 25% ground bone to graphite powder with introduced impurities did not affect the analytical signal of elements in the spectral excitation in a two-jet plasma. On basis of these investigations a method for direct multielement analysis of bone tissues was suggested. The sample preparation procedure consisted in mixing powdered bone (particle size 30 μm or less) with a spectroscopic buffer (graphite powder plus NaCl) in ratio 1:3 or to a greater extent depending on the analyte concentration. Reference samples based on graphite powder were used for construction of calibration curves. The NaCl concentration in analyzed and calibration samples was 15 wt%. The effect of particle size was revealed from the determination of Ba, Sr, and Mg. To eliminate this effect, treatment of the samples with nitric acid was proposed. The validation of the technique was confirmed by comparison of the analysis results of a bone sample with those obtained by inductively coupled plasma atomic emission spectrometry after wet acid digestion. The limits of detection estimated for 20 elements were the following (μg g^-1): 0.1 (Ag), 1.0 (Al), 1.0 (Ba), 0.1 (Be), 1.2 (Bi), 0.4 (Cd), 1.0 (Co), 0.2 (Cu), 0.6 (Cr), 1.9 (In), 2 (Fe), 0.3 (Ga), 0.4 (Mn), 0.4 (Mo), 0.7 (Ni), 1.0 (Pb), 0.7 (Sn), 0.8 (Tl), 5 (Sr), 1.0 (Zn).     

Simultaneous determination of trace metals in sewage and sewage effluents by inductively coupled argon plasma atomic emission spectrometry

Inductively coupled plasma excitation sources are adapted for the simultaneous determination of multiple elements in sewage and sewage effluents by atomic emission detection. Digestion with aqua regia in test tubes is recommended for sample preparation. A typical comparison of lead in sewage by atomic emission (x) and atomic absorption (y) gave a least-squares fit of x = 0.98 y + 0.03 with a standard error of 0.5 mg l^-1 and a correlation coefficient of 0.996. More complete comparison data by the atomic emission and absorption techniques are presented for other elements.     

Preconcentration by dithiocarbamate extraction for determination of trace elements in natural waters by inductively-coupled plasma atomic emission spectrometry

Preconcentration by dithiocarbamate extraction into 2-ethylhexyl acetate for simultaneous determination of trace elements in natural water is described. After 250-fold concentration, the organic phase is used directly for inductively-coupled plasma atomic emission spectrometry. Thirteen elements (As, Se, Mo, Zn, Cd, Ni, Co, Sn, Fe, Cr(VI), Pb, V and Cu) are simultaneously concentrated at pH 4.3 with the combination of ammonium tetramethylenedithiocarbamate and dibenzylammonium dibenzyldithiocarbamate and are determined in the extract; Mn and Cr(III) are also determined after preconcentration at pH 6.9 with the same chelating agents. Lake waters are analyzed by this method.