Microwave-assisted extraction of rare earth elements from petroleum refining catalysts and ambient fine aerosols prior to inductively coupled plasma-mass spectrometry

A robust microwave-assisted acid digestion procedure followed by inductively coupled plasma-mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM_2.5). High temperature (200 °C), high pressure (200 psig), acid digestion (HNO₃, HF and H₃BO₃) with 20 min dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst and PM_2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using ¹¹⁵In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu and Dy in ambient PM_2.5 in an industrial area of Houston, TX.     

Elemental content in ground and soluble/instant coffee

The concentration of thirty-four elements in twelve coffee brands has been measured using instrumental neutron activation analysis. The samples investigated included four brands of commercially available ground coffee and eight brands of soluble/instant coffee. The elements measured were Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Gd, Hf, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, Tm, U, V, Yb and Zn. Twenty four elements were found to be below the detection limit in one or more samples. These elements were Ce, Cr, Fe, V, As, Eu, Ba, Dy, Gd, Hf, La, Lu, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, Yb, Tm, and U.     

57Fe Mössbauer spectroscopy of banded iron formations from eastern India

Samples of the mosses Hylocomium splendens and Pleurozium schreberi, collected in the summer of 1998, were used to study the atmospheric deposition of heavy metals and other toxic elements in the Chelyabinsk Region situated in the South Urals, one of the most heavily polluted industrial areas of the Russian Federation. Samples of natural soils were collected simultaneously with moss at the same 30 sites in order to investigate surface accumulation of heavy metals and to examine the correlation of elements in moss and soil samples in order to separate contributions from atmospheric deposition and from soil minerals. A total of 38 elements (Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Rb, Sr, Zr, Mo, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Ta, W, Au, Th, U) in soil and 33 elements Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Au, Th, U) were determined by epithermal neutron activation analysis. The elements Cu, Cd and Pb (in moss samples only) were obtained by atomic absorption spectrometry. VARIMAX rotated principal component analysis was used to identify and characterize different pollution sources and to point out the most polluted areas.     

Strategy for water analysis using ICP-MS

The developed strategy permits determination in three steps of sixty-seven elements using inductively coupled plasma mass spectrometry (ICP-MS). Sodium, Mg, Si, S, Cl, K, and Ca are determined in a first step; B, Al, P, Cr, Fe, Mn, Ni, Cu, Zn, As, Se, Ag, Cd, Sb, Ba, Hg, and Pb are determined in a second step; and Li, Be, Ti, V, Co, Ga, Ge, Br, Rb, Sr, Y, Zr, Nb, Mo, Sn, Te, I, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Pt, Au, Tl, Bi, Th, and U are analyzed in a third step. The figures of merit obtained are adequate to carry out water quality monitoring and other hydrochemical studies, such those based in the application of hydrochemical fingerprinting to water management.     

NAA and ICP analysis of obsidian from Central Europe and the Aegean: Source characterisation and provenance determination

INAA and ICPES are compared for their discriminative power in obsidian source characterisation. Geological samples from the Aegean and Carpathian sources were analysed for Na, Sc, Fe, Co, Rb, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th, U by INAA and for B, Na, Mg, Al, K, Ca, Sc, Ti, Mn, Fe, Zn, Y, Yr, Cs, Ba, La, Ce, Sm, Eu, Gd, Tb, Yb, Lu, Hf by two ICPES procedures. It is shown that all techniques work successfully, however, INAA is more efficient in the chemical discrimination of neighbouring sources.     

Room temperature acid sonication ICP-MS multielemental analysis of milk

Room temperature acid sonication of milk samples is proposed as a fast alternative methodology for the determination of the total content of 45 elements (Li, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Mo, Ag, Cd, In, Sn, U, Sb, Te, Cs, Ba, Hg, Pb, Bi, Th, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Hf and Ta) in milk by inductively coupled plasma mass spectrometry (ICP-MS). The aforementioned procedure involves a 10 min sample pre-treatment. Measurements were made in quantitative and semiquantitative (Totalquant^®) modes of analysis using Rh as internal standard and Be, Ge, Tb and Re for internal calibration of the equipment in the semiquantitative mode. The selected isotopes were in general the most abundant ones of each element, except in cases where polyatomic or isobaric interferences were detected. Results of total concentrations in 10 liquid and 11 powdered commercially available milk samples were presented. Method validation was performed by measuring a SRM NIST-1549 non-fat milk powder and through the use of recovery experiments. Additionally, the proposed methodology was compared with a method based on a previous microwave-assisted digestion of samples and a direct analysis of 1:4 diluted samples.     

Multielement standards in routine reactor neutron activation analysis

The application of multielement standards (MES) in routine neutron activation analysis brings a whole range of advantages. This paper deals with the experience obtained during many years of application of these MES. Nine of these MES contain a total of 50 elements in suitable combinations and concentrations; thus, the determination of most of the common elements by NAA can be carried out simultaneously. This refers to the following elements: Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Mo, Ag, Cd, In, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, W, Re, Au, Hg, Th and U. For the determination of the remaining elements such as Zr, Ta, Ir etc., single element standards (SES) are used.     

Intercomparison of moss reference material by different multi-element techniques

An intercomparison of data obtained for a moss reference material (Hylocomium splendens) used as biomonitor of atmospheric deposition by different multi-element techniques is presented. In total 43 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, W, Au, Th, U) were determined using inductively coupled plasma-mass spectrometry (ICP-MS), conventional instrumental neutron activation analysis (INAA), epithermal neutron activation analysis (ENAA) and as well as shorttime neutron activation analysis without and with a⁶LiD-converter. Advantages and drawbacks of each method are discussed. The introduction of moss reference materials for atmospheric multi-element deposition studies involving nuclear analytical techniques is strongly recommended.     

南极岩石样品中稀土元素的中子活化分析

用仪器中子活化分析技术,测定了南极岩石中8种稀土元素含量,讨论了不同岩石的稀土模式特点。     

Determination of elements in SRM soil 2709a by neutron activation analysis

A combination of instrumental neutron activation analysis (INAA) and prompt gamma-ray activation analysis (PGAA) was used to value assign 35 elements in SRM soil 2709a (San Joaquin Soil). INAA with counting of short-lived radioisotopes was used for determination of Al, Au, Ca, Dy, K, Mg, Mn, Na, Ti, and V. Elements determined by INAA with counting of intermediate and long-lived radioisotopes included As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Yb, Zn, and Zr. Thermal neutron PGAA was used for the determination of H, B, Si, K, Ti, Mn, Fe, Cd and Gd. Expanded uncertainties were determined for all values reported.     

Analysis of molybdenum oxide by inductively coupled plasma atomic emission and mass spectrometry

Procedures for the analysis of molybdenum oxide by of inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectrometry (ICP-MS) are proposed on the basis of preliminary extraction separation of molybdenum from impurity elements. To separate 39 impurity elements (Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Zn, Ga, Rb, Sr, Y, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Bi, Th, and U), the extraction of molybdenum from hydrochloric acid solutions using 5-n-pentylthio-8-hydroxyquinoline was used. The capacities of both methods ICP-AES and ICP-MS in the analysis of molybdenum oxide analysis were examined without the removal of the matrix and after the extraction separation of molybdenum.     

Resonance neutrons for determination of elemental content of moss,lichen and pine needles in atmospheric deposition monitoring

Experience in the use of epithermal neutron activation analysis (ENAA) in the monitoring of atmospheric deposition by means of moss, lichens and pine needles is summarized. It is shown that 45 elements (Mg, K, Ca, Al, Cl, Sc, V, Cr, Mn, Fe, Co, Ni (using (n,p)-reaction), Zn, Cu, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, W, Au, Th and U, as well as Ir and Re in pine needles in the presence of anthropogenic pollution by the nickel mining plant) are reliably determined. Examples of the use of lichens, moss and pine needles as biomonitors of atmospheric deposition in Franz Josef Land the Kola peninsula and in the Tver region are given.     

Determination of 30 elements in coal and fly ash by thermal and epithermal neutron-activation analysis

Thirty elements are determined in coal and fly ash by instrumental neutron-activation analysis using both thermal and epithermal irradiation. Gamma-ray spectra were recorded 7 and 20 days after the irradiations. The procedure is applicable to the routine analysis of coals and fly ash. Epithermal irradiation was found preferable for the determination of Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, Cs, Ba, Sm, Tb, Hf, Ta, W, Th and U, whereas thermal irradiation was best for Sc, Cr, Fe, Co, La, Ce, Nd, Eu, Yb and Lu. Results for SRM 1632 (coal) and SRM 1633 (fly ash) agree with those of other investigators.     

INAA of Some Fossil Samples from Romanian Sites

Instrumental neutron activation analysis was used to determine elemental contents of Elephas primigenius mammoth mandible bone and Pecten solarium shell fossils discovered in Romania during 1995–1996. In addition, calcareous sedimentary rock surrounding the shell fossil was analyzed. Concentrations of Al, As, Au, Ba, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Mg, Mn, Na, Ni, Rb, Sb, Sc, Se, Sr, Th, U, V, Zn and the rare earth elements Ce, Eu, La, Lu, Nd, Sm, Tb, Yb were determined. The results are discussed and compared to the available data in the literature for similar fossils.     

Measurement of K β /K α intensity ratios for elements in the range 51 ≤ Z ≤ 67 at 59.54 keV

K-shell X-ray intensity ratios for some elements Sb, Cs, La, Ce, Pr, Nd, Sm, Gd, Dy and Ho have been measured experimentally. The elements were excited by 59.5 keV γ-ray from 100 mCi ²⁴¹Am radioactive source. The characteristic K X-rays emitted by samples were detected by using a hyper pure germanium detector. The experimental results were compared with theoretical predictions reported by several authors.     

Determination of 34 elements in Chinese geochemical standard reference materials by instrumental neutron activation analysis

Thirty four elements (Al, As, Ba, Br, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Gd, Hf, Ho, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, Ti, U, V, W, Yb) were determined by instrumental neutron activation analysis in the second set of Chinese geochemical standard reference materials (sediments from GSD-9 to GSD-12, soils from GSS-1 to GSS-8, rocks from GSR-1 to GSR-6) using both thermal and epithermal irradiations. Irradiation schemes designed to utilise short, medium and long-lived nuclides were employed in order to analyse major, minor and trace elements with different half-lives. The gamma-ray spectra were measured by Ge(Li) and HP(Ge) detectors. Relevant nuclear data and possible interferences are listed, and analytical results are presented and discussed.     

Regularities of change in the structural parameters of EuLnCuS<Subscript>3</Subscript> (Ln = La–Nd,Sm, Gd,Ho)

Regularities of change in the structural parameters of EuLnCuS₃ (Ln = La–Nd, Sm, Gd, Ho) at an annealing temperature of 970 and 1170 K have been established. A decrease in the Ln³⁺ ionic radius results in the consecutive change of structural types (STs) for the compounds: α-EuLnCuS₃ (Ln = La, Ce, Pr, Nd; BaLaCuS₃ ST) → β-EuLnCuS₃ (Ln = Ce, Pr, Nd; Ba2MnS₃ ST) → γ-EuLnCuS₃ (Ln = Sm, Gd, Ho; Eu₂CuS₃ST). The change of structural types for EuLnCuS₃ leads to a jump-like change in their unit cell parameters and the transformation of coordination polyhedra shaped as a one-capped trigonal prism LnS₇ (α and β phases) into an octahedron LnS₆ (γ phases). The appearance of morphotropic changes correlates with the tetrad effect.     

Mg(OH)_2共沉淀和直接稀释联用ICP-MS法准确测定海水中的多种常量-微量元素

对海水中多种常量/微量元素分别用Mg(OH)_2共沉淀和直接稀释ICP-MS法进行方法比较研究,分别确定了这些元素适宜的准确分析方法,为海水中常量/微量元素的ICP-MS测定提供了实用的检测手段。结果表明,Mg(OH)_2共沉淀法能够实现对V,Cr,Mn,Co,Cd及稀土元素(La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu)等19种微量元素的分离富集和准确测定;10倍直接稀释法能够同时准确测定海水中B,Sr,Li,Rb,I,V,Cr,As,Cd,U,Mo,Cu,Mn 13种微量元素,但不适合Zn,Ni,Co和Pb,以及稀土元素等在海水中浓度过低元素的测定;两种方法对适宜测定的元素均操作简便快速,具有较高的准确度和精密度。这两种方法联用,就可用约50 mL的海水实现大洋和近海海水中Co,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu(这15个元素采用Mg(OH)_2共沉淀法)及B,Sr,Li,Rb,I,V,Cr,As,Cd,U,Mo,Cu,Mn(这13个元素采用10倍直接稀释法)等28种元素的准确测定。     

Moss as monitor of heavy metal deposition: Comparison of different multi-element analytical techniques

Instrumental activation analysis (INAA) based on irradiations in a nuclear reactor with particularly high relative fluxes of resonance and fast neutrons has been shown to open new possibilities for multi-element surveys of mosses used as monitors of atmospheric deposition. Comparison is made with data obtained by inductively coupled plasma-mass spectrometry (ICP-MS) and conventional INAA. Data for 15 elements not previously investigated in routine moss studies are presented, e.g., Zr, Sn, Hf, Ta, W, Au, Th, and the rare earth elements Ce, Nd, Eu, Gd, Tb, Tm, Yb, Lu. Other elements particularly well determined by this approach are Sc, Co, As, Ag, Sb, Cs, La, Sm, Th, and the non-metallic trace elements Se, Br, and I. Advantages and drawbacks with the high fast neutron component are discussed.     

A group separation scheme for radiochemical neutron activation analysis for 24 trace elements in rocks and minerals

A group separation scheme has been developed for radiochemical neutron activation analysis for Ca, Cu, Zn, Ga, Rb, Sr, Zr, Sb, Cs, Ba, La, Nd, Sm, Eu, Gd, Tb, Ho, Tm, Yb, Lu, Hf, Ta, W and Th in a wide variety of silicate rocks and minerals, especially ultrabasic rocks and mafic minerals. The samples are decomposed in a hydrofluoric acid-nitric acid mixture in a PTFE-lined bomb. The soluble fluorides (Cu, Zn, Ga, Rb, Zr, Sb, Cs, Ht, Ta, W and Pa) are separated into three groups of elements by sequential elution from a cationexchange resin. The insoluble fluorides (Ca, Rb, Sr, Cs, Ba and REE) are dissolved and purified from interfering iron and scandium activities by extraction with tri-n-butyl phosphate. If necessary, the four main groups can be purified further from interfering activities such as ⁵⁹Fe, ⁵¹Cr and ⁶⁰Co. The accuracy and reproducibility of the procedure were tested by repeated analysis of U.S. Geological Survey standard granite G-2, andesite AGV-1 and dunite DTS-1.