Determination of minor and trace elements in silicate rocks by inductively-coupled plasma emission spectrometry

Samples (0.5 g) are decomposed with mixed acids in a sealed teflon vessel. After suitable treatment, barium, cobalt, chromium, copper, lithium, nickel, scandium. strontium, vanadium and zirconium are determined sequentially. The method is satisfactory for a variety of standard silicate materials.     

Determination of traces of zirconium in silicate rocks by inductively-coupled plasma emission spectrometry

The sample is fused with a mixture of sodium and potassium carbonates. Zirconium is separated from the large amounts of sodium and potassium by precipitation of hydrated oxides before nebulization. The detection limit is 0.32 μg Zr g^-1. Results for seven standard rocks are in accord with recommended values.     

Determination of rare-earth elements,yttrium and scandium in manganese nodules by inductively-coupled argon-plastma emission spectrometry

A sequential-scanning, inductively-coupled argon plasma emission spectrometer is used for the determination of the rare-earth elements, plus yttrium and scandium, in manganese nodules. Wavelength selection is optimized to minimize spectral interferences from manganese nodule components. Samples are decomposed with mixed acids in a sealed polycarbonate vessel, and elements are quantified without further treatment. Results for U.S. Geological Survey manganese nodule standards A-1 and P-1 had average relative standard deviations of 6.8% and 8.1%, respectively, and results were in good agreement with those obtained by other methods.     

Determination of yttrium and rare-earth elements in rocks by graphite-furnace atomic-absorption spectrometry

With use of synthetic solutions and several international standard reference materials a method has been developed for determining traces of Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in rocks by electrothermal atomization in a pyrolytically-coated graphite furnace. Depending on the element, the sensitivity is of the order of 10(-9)-10(-12) g at 2500 degrees . To avoid matrix interferences the lanthanides are separated from the common elements by co-precipitation with calcium and iron as carriers. The data for Canadian reference rock SY-2 (syenite), U.S.G.S. reference rocks W-2 (diabase), DNC-1 (diabase) and BIR-1 (basalt), and South African reference rock NIM-18/69 (carbonatite) obtained by graphite-furnace atomization are compared with the values obtained by flame atomic-absorption. The results are in good agreement with literature values.     

Determination of rare-earth elements by high-performance liquid chromatography/inductively-coupled plasma/atomic emission spectrometry

Liquid chromatography coupled on-line to a sequential ICP/AES system is applied for the determination of 14 rare-earth elements (REEs) in samples with widely different concentrations of REEs and matrix elements. The REEs are separated on a cation-exchanger by applying an α- hydroxyisobutyric acid gradient. The determination limits were the same as those obtained by continuous nebulization of single-element standard solutions. The chromatographic separation precludes mutual spectral interferences between the REEs. The practical value of the method developed is demonstrated by the determination of REE impurities in Specpure rare-earth oxides, by its demonstrated potential to evaluate real spectral interferences, and by the analysis of geological samples (natural phosphates) with relatively low total REE contents. The detection limits of REEs in these natural phosphates ranged between 0.005 and 0.4 μg g^?1.     

Determination of trace elements in sea water by inductively-coupled plasma emission spectrometry

Pb, Zn, Cd, Ni, Mn, Fe, V and Cu in sea water are determined by extraction of their complexes with sodium diethyldithiocarbamate into chloroform, decomposition of the chelates and inductively-coupled plasma emission spectrometry. When 1-l water samples are used, the lowest determinable concentrations are: 0.063 μg Mn l^-1, 0.13 μg Zn l^-1, 0.25 μg Cd l^-1, 0.25 μg Fe l^-1, 0.38 μg V l^-1, 0.5 μg Ni l^-1, 0.5 μg Cu l^-1, and 2.5 μg Pb l^-1. Above these levels, the relative standard deviations are better than 12% for the complete procedure.     

Determination of ten rare-earth elements and yttrium in silicate rocks by ICP-AES without separation and preconcentration

Lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium and yttrium have been determined in 8 international rock standards by inductively coupled plasma atomic emission spectrometry (ICP-AES) without prior ion-exchange separation and preconcentration. The results for La, Ce, Nd, Eu, Dy, Yb and Y were in good agreement with the reported values, whereas those for Sm, Gd, Er and Lu were less accurate. However, the results for Sm, Gd, Er and Lu can also be used for studies of petrogenesis.     

Laser-excited ionic fluorescence spectrometry of rare-earth elements in the inductively-coupled plasma

A pulsed tunable dye laser pumped with an excimer laser is used to excite ionic fluorescence of the rare earth elements in the inductively-coupled plasma. Because several fluorescence lines were observed after laser excitation, it was possible to draw partial energy-level diagrams for most of the rare earths. Non-resonance fluorescence lines were used for all measurements in order to minimize spectral interferences. Detection limits at given excitation wavelengths are reported for each element. Laser-excited ionic fluorescence eliminates the problem of spectral interferences which has been associated with the determination of the rare earths by atomic emission spectrometry in the inductively-coupled plasma.     

Determination of the rare-earth elements in geological materials by thin-film X-ray fluorescence and inductively-coupled plasma atomic-emission spectrometry

Thin-film XRF and ICP-AES analytical procedures for the determination of the rare-earth elements (REE) in rocks, involving preconcentration by ion-exchange and co-precipitation with Fe(OH)(3) for thin-film preparation, and matrix modification, are described. The REE in five international reference rocks have been determined, with correction for spectral line overlap whenever necessary. The results obtained by using X-ray fluorescence spectrometry compare well with those of inductively-coupled plasma atomic-emission spectrometry, and with other values reported in the literature.     

Determination of boron in geological materials by inductively-coupled plasma emission spectrometry

Determination of boron in international silicate reference materials with an argon plasma is demonstrated. Detection limits are about 5 ppm for rock samples.     

Determination of phosphorus in waste-waters by inductively-coupled plasma atomic emission spectrometry

Inductively coupled plasma—atomic emission spectrometry offers a simple and rapid method for the determination of total phosphorus in waste-waters: the optimum operating conditions are described. The detection limits are 0.02, 0.04, and 0.11 μg ml^-1 at the 213.618, 214.914, and 253.565-nm lines, respectively. Interferences by other elements are negligible at the concentration levels of these elements in environmental and waste-waters, except for the spectral interference of copper on the lines at 213.618 and 214.914 nm. Differences in emission response for various inorganic and organic phosphorus compounds are small. Analytical results for phosphorus in municipal and industrial waste-waters agree well with those obtained by standard methods.     

Determination of some rare-earth elements by plasma-jet emission spectrometry

The effects of a magnetic field on spectral intensities in plasma-jet spectrometry were examined, and detection limits for rare-earth elements were calculated. Plasma-jet emission spectrometry was applied to the determination of lanthanum, yttrium and gadolinium in a monazite sample from which thorium had been separated. A standard addition method was used in order to improve accuracy, and the internal standard and background compensation method was applied to measurements of spectral line intensities to achieve good precision. The coefficient of variation was 1.51% for 50 μg La ml^?1.     

Simultaneous determination of 14 lanthanides and yttrium in rare earth ores by inductively-coupled plasma atomic emission spectrometry

A method is described for simultaneous determination of 14 lanthanides and yttrium in monazites and xenotimes by inductively-coupled plasma atomic emission spectrometry. The ore samples were decomposed by heating with nitric acid/perchloric acid or hydrofluoric/nitric/perchloric acids, or sulfuric acid, or by fusion with sodium carbonate. Among these methods, treatment of the samples with sulfuric acid, by evaporation to dryness followed by dissolution of the residue with hydrochloric acid is recommended; it provided complete decomposition for the five monazites and xenotimes examined. The accuracy and precision of the results were significantly influenced by spectral interferences of the rare earth elements themselves; correction methods and factors are given. The chondrite-normalized rare-earth patterns were examined to characterize the monazite and xenotime samples.     

Determination of sulfur in biological samples by vacuum-ultraviolet inductively-coupled plasma atomic emission spectrometry

Sulfur is most sensitively determined at 180.7 nm, the detection limit being 10 μg l^?1. A comparison of digestion procedures shows that acid digestion in a teflon bomb gives least loss of analyte. Only calcium interferes spectrally at this wavelength. Results for various reference materials are presented.     

Determination of rare earths in lanthanum oxide by inductively-coupled plasma emission derivative spectrometry

Rare-earth elements (REE) at ppm levels in lanthanum oxide can be determined without prior separation and preconcentration by use of high-resolution inductively-coupled plasma emission derivative spectrometry (ICPEDS). The calibration graphs are all linear and pass through the origin, even in the presence of large amounts of lanthanum, except those for dysprosium, holmium and ytterbium. The detection limit for each REE is 1-10 mug g in lanthanum oxide. Investigation of various physical and/or spectral interferences shows that good selectivity is obtained by ICPEDS.     

Screening for selected toxic elements in urine by sequential-scanning inductively-coupled plasma atomic emission spectrometry

A rapid screening method for nine elements (Se, As, Cr, Zn, Cd, Pb, Ni, Mn, and Cu) in human urine is described. A sequential-scanning inductively-coupled plasma atomic emission spectrometer, incorporating a cross-flow nebulizer, was used. Internal standardization with yttrium compensated for the differences between the aqueous calibration standards and the undiluted urine specimens. Accuracy was evaluated with aqueous (NBS SRM 1643a, EPA 378-13, and EPA 476-3) and urine (NBS SRM 2670 and Fisher Urichem Level II) reference and control materials. Detection limits for the system were evaluated from analyses of normal urine materials found to contain low levels of the elements investigated.     

Determination of the rare-earth elements in phosphate rocks using both inductively coupled plasma atomic emission spectrometry and instrumental neutron activation analysis

Rare earth elements have been determined in Syrian phosphate rocks by two methods: inductively coupled plasma atomic emission spectrometry following a cation separation, and instrumental neutron activation analysis using both short and long irradiation periods. The results from the two methods agree in most cases apart from Ce, Lu, Nd and Sm. Despite the absence of reliable reference materials, we believe the emission spectrometry technique to be the more accurate.     

Evaluation of sequential and simultaneous detection in inductively-coupled plasma emission spectrometry of complex samples

A commercially available inductively-coupled plasma (i.c.p.) polychromator system and a laboratory-constructed i.c.p. sequential detection system are evaluated. Some previous studies are reviewed and theoretical expectations are compared to experimental data. The precision and detection limits of the two systems are approximately equivalent. Difficulties commonly encountered with complex samples, including background interferences, spectral overlap, and determinations beyond the linear range of an element are studied. The abilities of each instrument to circumvent these difficulties at different interference levels are evaluated. The wavelength flexibility of the sequential system is demonstrated to be advantageous in dealing with these interferences. Each instrument was evaluated for NBS spinach, NBS river sediment, volcanic ash, and refractory brick. The complementary nature of the sequential system and polychromator with respect to method development and quantitative work is discussed.     

Automated inductively-coupled plasma optical emission spectrometry based on a sequential reading monochromator

An automated computer-controlled sequential reading monochromator system for optical emission spectrometry with an inductively-coupled plasma as source is described. The system selects the set of emission lines which are best suited for each type of sample. Multi-element analysis of major and trace elements is done automatically, including sample changing, calibration, background correction and presentation of results.