Solvent extraction of Sb(III) with malachite green into chloroform

A rapid and selective method for the solvent extraction of Sb(III) using malachite green (C. I. Basic green 4) has been described. Effect of different parameters affecting the extraction coefficient value of Sb(III) such as acidity, time of equilibration, KI concentration, solvents, anions, etc. has been studied. For various elements the separation factor has been evaluated. The stoichiometry of the extracted species has been determined by the method of substoichiometric extraction. The decontamination factor for some elements using substoichiometric quantities of the extracting agent has been evaluated. Radiotracers were employed for the extraction studies. The method elaborated has been employed for the quantitative determination of antimony in normal, benign and cancerous tissues of the human brain.     

Removal of sodium and chlorine from seawater prior to neutron activation analysis for trace elements

A neutron activation analysis (NAA) method has been developed for the determination of 14 elements in seawater samples. The method consists of pre-irradiation separations of interfering elements, viz. Na with hydrated antimony pentoxide, leached Sb using either acid aluminum oxide or tin dioxide, and Cl and Br with a mixture of nitric acid and hydrogen peroxide, followed by 3 different irradiation, decay and counting periods. Concentrations of Ag, Co, Cr, Cu, Fe, La, Lu, Mn, Mo, Sc, Sm, Ti, V and Zn have been measured and compared with those obtained by an independent preconcentration method. Precision and limits of detection and determination have been evaluated.     

Diagnostic and analytical study of post ablation ionization of neutral atoms of major and minor constituents from a low alloy steel

Post ablation ionization (PAI) of neutral atoms from a low alloy steel has been investigated using non-resonant laser ionization in a time-of-flight mass spectrometer. By varying the delay between the ablation and ionization lasers, the velocity distributions of the Ti, V, Cr, Mn and Fe atoms have been determined simultaneously. These distributions have been recorded as a function of ablation laser fluence. The half-range Maxwell-Boltzmann velocity distribution has been used to fit the data and different characteristic temperatures have been determined for the various elements in the sample. The quantitative capability of this method for bulk and surface analysis has been evaluated by calculating the relative sensitivity factors (RSFs) for the various constituent elements. The RSFs for all of the elements are seen to be highly dependent on the delay between the ablating and ionizing lasers. This dependence was reduced by integrating the temporal dependent ion yield, leading to a significant improvement in the calculated RSF values. It was also found that the RSFs were not highly dependent on the power density of the ablation laser beam.     

A method for the separation of beryllium from spectral interfering elements in inductively coupled plasma-atomic emission spectroscopic analysis

A quick, simple and effective chromatographic method for the separation of beryllium from a wide range of elements is described. The elements selected comprise elements which can interfere with the determination of beryllium by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and elements which commonly occur in environmental and industrial sample matrices. Beryllium is separated from all possible ICP-AES spectral interfering elements using a single extraction chromatographic (EXC) cartridge containing an acidic chelating organophosphorus extractant, Dipex^®, sorbed onto an inert polymeric substrate. The separation method has been evaluated using simulated samples generated using several different digestion methods currently employed in beryllium analyses performed in Department of Energy (DOE) facilities. Incorporating a guard cartridge containing either 2-ethyl-1-hexylphosphonic acid mono 2-ethyl-1-hexyl ester or bis(2,4,4-trimethylpentyl)phosphinic acid to selectively remove U(VI) allows the isolation of beryllium from samples containing over 100 mg of uranium without changing the load, rinse or strip conditions of the method.     

Determination of protein-bound trace elements in bovine kidneys

Concentrations of up to 16 elements have been determined in subcellular fractions of bovine kidney using INAA methods. Levels of Rb and Se have been measured by a cyclic INAA method. A conventional INAA method consisting of 2 irradiations and 3 counting periods has been employed to determine the other elements. Accuracy of measurements has been evaluated by analyzing several standard reference materials. Trace element content of reagents used has been investigated in detail. Fresh samples of bovine kidney have been homogenized in a buffer containing sucrose and HEPES, and the homogeneate separated into nuclei, mitochondrial, lysosomal, microsomal and cytosol fractions by successive differential centrifugation. Concentrations of trace elements have been measured in these fractions using the INAA methods.     

Determination of elements in paints and paint scrapings by inductively coupled plasma atomic emission spectrometry using microwave assisted digestion

Summary Inductively coupled plasma atomic emission spectrometry (ICPAES) is applied to the determination of elements in paints and paint scrapings to evaluate potential occupational and environmental exposure to metals in paints. A microwave assisted digestion procedure of these materials using nitric and hydrofluoric acid mixtures under controlled pressure has been developed. The accuracy and repeatability of the recommended procedure for lead are documented and evaluated by analysing NIST SRM 1579 Powdered Lead Based Paint. Neutron activation analysis was applied as a reference method for other elements. A variety of industrial and domestic paints of different chemical composition were analysed. The advantages and limitations of microwave digestion of paints are discussed.     

A simple method of target preparation for the bulk analysis of powder samples by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

A simple and rapid procedure using a glue technique has been developed for the preparation of stable targets from powder samples for bulk analysis by LA-ICP-MS. The procedure was evaluated for the analysis of trace elements in SiC, of rare-earth elements in different types of silicate (rocks, sediments, and soils), and of Au and platinum-group elements in geological silicates. The test analysis was conducted using an IR laser in combination with a quadrupole mass spectrometer. The recommended preparation procedure offers the possibility of different types of calibration, for example application of certified reference samples in combination with prepared spiked samples on a base of a natural or synthetic matrix, or addition calibration. The resulting calibration functions are linear over a range of several decades. The trueness of the results was evaluated by use of certified reference samples. Analytical concentration ranges, detection limits, and the relative standard deviations are reported.     

Preconcentration and instrumental neutron activation analysis of acid rain for trace elements

A combination of instrumental and preconcentration neutron activation analysis (NAA) methods has been developed for multielement determination in acid rain. Concentrations of 24 elements have been measured in the particulate matter of rainwater by the instrumental NAA method which involves 3 irradiation and 4 counting periods. Trace elements in the soluble fraction of rainwater have been preconcentrated using Chelex-100 resin. Various factors that could influence the retention of elements on to the resin have been examined, and reagent and other blanks investigated in detail. Concentrations of 15 elements have been measured by directly irradiating the resins. A graphite furnace atomic absorption spectrometry method has been used for determining Cd and Pb levels in the soluble fraction. Precision and accuracy of the methods have been evaluated, and limits of detection and determination calculated. The methods have been applied to rainwater samples collected from 36 locations across Canada. Enrichment factors, interelement and inter-ion concentration correlation coefficients are discussed     

Liquid-liquid extraction of elements by antipyrine and diantipyrylmethane salts from non-aqueous solutions or in systems without an organic solvent

The liquid-liquid extraction method for inorganic compounds has been developed and further improved by using different types of multiphase systems involving pyrazolone derivatives. The degree of concentration of elements by use of three-phase liquid systems has been increased by 1-2 orders of magnitude, and a universal method for preconcentration of elements in non-aqueous media has been suggested. The development of extraction systems based on a single liquid component-water-and not requiring an organic solvent at all, has increased the safety of extraction methods and improved the working conditions. A new variant of spectrochemical analysis without mineralization of an extract has been developed. Its main advantage is that it reduces the analysis time by a factor of 6 or 8. The liquid-liquid extraction of elements in purely aqueous two-phase systems without an organic solvent can be combined with titrimetric, photometric and polarographic determination in hybrid analytical procedures.     

A simple method of target preparation for the bulk analysis of powder samples by laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS)

A simple and rapid procedure using a glue technique has been developed for the preparation of stable targets from powder samples for bulk analysis by LA– ICP–MS. The procedure was evaluated for the analysis of trace elements in SiC, of rare-earth elements in different types of silicate (rocks, sediments, and soils), and of Au and platinum-group elements in geological silicates. The test analysis was conducted using an IR laser in combination with a quadrupole mass spectrometer. The recommended preparation procedure offers the possibility of different types of calibration, for example application of certified reference samples in combination with prepared spiked samples on a base of a natural or synthetic matrix, or addition calibration. The resulting calibration functions are linear over a range of several decades. The trueness of the results was evaluated by use of certified reference samples. Analytical concentration ranges, detection limits, and the relative standard deviations are reported. Received: 20 November 2000 / Revised: 13 March 2001 / Accepted: 17 March 2001     

Comparative study of different digestion procedures using supplementary analytical methods for multielement-screening of more than 50 elements in sediments of the river Elbe

The suitability of four different digestion procedures, i.e. i.) an aqua regia digestion according to DIN 38 414-S7, ii.) a pressure digestion using HNO₃/HF in PTFE-vessels, iii.) a HNO₃/HF + HCl-pressure digestion in PTFE-vessels and iv.) a HNO₃/HF + HCl-pressure digestion using microwave induction, has been evaluated with regard to the quantitative determination of about 50 elements in environmental samples. Three sediments of the river Elbe and two standard reference materials (MESS-1 and NIST 1645) have been employed. The analytical results from the dissolved samples, obtained using inductively coupled plasma mass- and optical emission spectrometry as well as total reflection X-ray fluorescence spectrometry, have been compared with those obtained by instrumental neutron activation analysis. Only digestion procedures using HNO₃/HF with a subsequent evaporation to dryness and dissolution in HCl have led to appropriate results for a wide range of elements (more than 50 elements in total). Because of its low contamination risk and its time saving, the microwave digestion is preferred. For this digestion procedure the accordance among the different instrumental methods used is high (better than 15% deviation) in general. A few elements (16) could be determined quantitatively only by a single method.     

Determination of 22 elements in geological samples by instrumental neutron activation analysis

An instrumental neutron activation analysis (INAA) method has been developed for multi-element determination in geological samples. The INAA method consists of irradiation of samples for 90 sec at a flux of 1.0·10¹² n·cm⁻²·sec⁻¹ and determination of 12 elements by using their short-lived nuclides. Samples have been re-irradiated for 3 hrs for measuring concentrations of another 10 elements. Precision and accuracy of the INAA method have been evaluated by analysing samples and USGS standard reference materials. Precision and accuracy are within±15% and ±10%, respectively.     

Multiresidue Analysis of Some Insect Growth Regulators by Reversed-Phase High-Performance Liquid Chromatography

Abstract

A general procedure has been developed for the analysis of 8 different insect growth regulators (IGRs) by using reversed-phase high-performance liquid chromatography with gradient solvent systems. The method has been used to identify and separate 8 insect growth regulators from a mixture of the standards. The method has been evaluated with different column conditions and under different solvent systems. Best resolution was obtained by using a double column and methanol/water gradient system.     

Solvent extraction of Au(III) using 2-mercaptobenzimidazole into n-butanol

A method has been developed for the extraction of Au(III) with 2-mercaptobenzimidazole into n-butanol.¹⁹⁹Au has been used as a tracer for establishing the ideal extraction parameters such as effect of pH, time of equilibration, solvents and anions. Separation factor and decontamination factor have also been evaluated to determine the selectivity of the method with respect to various elements. The interfering elements were suppressed by the use of suitable masking agents which increased the selectivity. The stoichiometry of metal to reagent was determined by the method of substoichiometric extraction and slope ratio method.     

Measurement of total and photoelectric cross sections of rare earth elements present in compounds for 123.6 keV and 145.4 keV photons

A new, simple and direct method proposed earlier by us has been employed here to measure the total photoelectric cross section of rare earth elements in the range 58 Z 66 present in compounds at 123.6 keV and 145.4 keV photon energies. The K X-ray fluorescence intensities emitted by these elements, from irradiating their compounds by the photons of above energies, are measured using a NaI (Tl) spectrometer system in a 2π geometrical configuration. The K X-ray fluorescence cross sections of the rare earth elements are determined, from which the total photoelectric cross sections are evaluated. Total mass attenuation coefficients of compounds for the K X-ray and the incident radiations respectively have been measured and these values were compared with the corresponding theoretical values and a good agreement between them is obtained.     

Determination of tin in indium by neutron activation with pre-irradiation separation

A method has been developed for chemical control of a short-lived radiopharmaceutical,⁵²Fe. The optimum conditions have been investigated for the simultaneous determination of microgram amounts of nickel, iron and chromium in an admixture. The method developed is applicable for the determination of 0.01 to 20 μg·ml^?1 of nickel, 0.01 to 50 μg·ml^?1 of iron and 0.05 to 50 μg·ml^?1 of chromium. A study has been made of the mutual interference of these elements at different concentrations, and also of the interference by various other cations and anions. A list has been given of the other elements that can be analysed using the supporting electrolyte. A method of routine analysis is described.     

Monte Carlo source simulation technique for solution of interference reactions in INAA experiments: a preliminary report

A new method using Monte Carlo source simulation of interference reactions in neutron activation analysis experiments has been developed. The neutron spectrum at the sample location has been simulated using the Monte Carlo code MCNP and the contributions of different elements to produce a specified gamma line have been determined. The produced response matrix has been used to measure peak areas and the sample masses of the elements of interest. A number of benchmark experiments have been performed and the calculated results verified against known values. The good agreement obtained between the calculated and known values suggests that this technique may be useful for the elimination of interference reactions in neutron activation analysis.     

The yields of photonuclear reactions for multielement photon-activation analysis

A comprehensive study on the yields of photonuclear reactions of various types has been performed, and sensitivities and the effects of interferences in multielement photon-activation analysis have been evaluated by bremsstrahlung activation of many elements with maximum energies ranging from 30 to 60 MeV. The applicability and reliability of the method were demonstrated by analyzing standard round-robin samples and then by presenting the elemental abundances in several geological, biological and environmental materials. The method was almost insensitive to matrix effects and was assessed to be promising for nondestructive multielement determination of the materials of wide variety, giving good reproducible results for 20 or more elements.     

硒和碲的HPIEC分离和测定

色谱法分离硒和碲,多以强酸为洗脱液[1,2],有关高效离子交换色谱法(HPIEC)分离硒、碲的工作,似尚未见报导。本文用HPIEC法在十分钟内分离并测定了硒和碲。     

Evaluation of combined measurement uncertainty of the determination of Mn content in sediment samples

Combined uncertainties of an analysis of elemental content of sediment samples were evaluated. A monitoring system has been designed and implemented for the characterization of the environmental conditions of Lake Balaton in Hungary. Sediments samples were collected and an acidic digestion method was used to determine the concentration of elements. For the calculation of the result of each measurement three different approaches were considered, namely a.) the calculation of the result using a calibration curve and estimating the confidence limit by the Student t-distribution, b.) calculation of the combined uncertainty and c.) estimation of the sampling errors using the transport and field blanks. The latter approach gave the most reliable result since it included all the parameters which had to be considered regarding sampling and sample handling, and measurement. Determination of acid soluble Mn content in sediment samples has been chosen as an example, and the combined uncertainty is calculated using blanks for sampling. Received: 17 March 2000 Accepted: 4 October 2000