Interelement Interferences Research Articles

Elimination of the inter-element interferences of iron, gold, molybdenum, tin and antimony when determined in organic solvents by flame atomic absorption spectrometry

The mutual interferences in the flame atomic absorption spectrometric determination of iron, gold, molybdenum, tin and antimony after their extraction-pre-concentration as chloride complexes from platinum solutions into isobutyl methyl ketone are investigated. It is suggested that the interferences are caused by chemical reactions in the flame and are influenced by the flame characteristics. The possibility of eliminating the interferences by addition of long-chain quaternary ammonium salts is discussed.

Oxide, Hydroxide, and Doubly Charged Analyte Species in Inductively Coupled Plasma/Mass Spectrometry

In inductively coupled plasma/mass spectrometry analyte, M may be distributed among several species forms including doubly charged ions (M2+), singly charged ions (M+), mono-oxide ions (MO+), and hydroxide ions (MOH+). Detailed data are presented for Ba to illustrate the dependence of the ion count of these species and their ratios (M2+/M+, MO+/M+, and MOH+/M+) on nebulizer flow rate, plasma power, and sampling depth. Although these data are representative of most elements, many form oxides to a much greater degree than Ba; data are presented for Ti, W, and Ce to illustrate this fact. These various analyte species are important in that serious interelement interferences can occur because of spectral overlap. An extensive pair of tables indicating potential spectral interferences caused by element oxide, hydroxide, and doubly charged ions is presented.

Some hydride generation inter-element interference studies utilizing atomic absorption and inductively coupled plasma emission spectrometry

Three commercially available hydride generation devices have been used in conjunction with atomic absorption spectrometry and inductively coupled plasma emission spectrometry to study the possible inter-element interferences from fifty elements. Nineteen of these elements caused signal reductions of at least 10%. These interferences were reduced (drastically in some cases) by an appropriate choice of hydride generation system and by manipulation of the acid strength.

Determination of Trace Elements in Boron by Instrumental Photon Activation Analysis

An instrumental photon activation analysis has been developed for the determination of trace elements in boron samples. A simultaneous irradiation of the sample and multielement standards with 30MeV bremsstrahlung produced by a linear electron accelerator for 2-3 hours was applied to measure levels for up to 28 elements nondestructively with practical limits of detection ranging from 0.02 to 10μg. Degrees of inter-element interferences were evaluated. Analytical results for boron samples are presented.

Analytical Characteristics of the Microwave-Induced Nitrogen Discharge at Atmospheric Pressure (MINDAP)

A microwave-induced plasma (MIP) is sustained at atmospheric pressure with the use of nitrogen as the plasma and nebulizer gas. The plasma is operated at 2450 MHz and has been optimized at 250 W of rf power with a total nitrogen flow rate of 1.78 L/min. The analytical performance of this plasma has been evaluated and compared with other atmospheric pressure plasma systems. Detection limits were typically in the part-per-billion concentration range, and calibration curves were linear over three-to-five orders of magnitude. Interelement interferences were observed but were overcome with the use of releasing agents. Precision for an analytical measurement was generally better than 2°/o relative standard deviation.

Determination and distribution of trace elements in marine invertebrates.

Inductively coupled plasma atomic fluorescence spectrometry (ICP-AFS) was applied to the determination of trace elements in edible parts of marine invertebrates. Element contents (except aluminium and lead) in the NBS standard reference material 1566: oyster tissue measured by ICP-AFS were in agreement with certified values. Furthermore, analytical results indicated that ICP-AFS is one of the effective multielement analyses, because of a simultaneous determination capability, large dynamic ranges, small interelement interferences, and a satisfactory precision.From the investigation of the elemental distribution in marine invertebrates, the highest concentrations of transition elements were found in the kidney of the scallop. It was found that the liver of the lobster contained high levels of copper and cadmium. Especially, the cadmium concentration in the liver was about two thousand times higher than that of the abdominal muscle.Gel filtration profiles (Sephadex G-75) of iron, copper, zinc and cadmium in livers of marine organisms varied according to species. Moreover, a significant difference in the chromatogram of copper was observed among the oyster samples collected from five sampling sites. The ratio of the third peak area indicating the lowest molecular weight (below 5, 000) to the whole was related to the total amount of copper in the liver of the oyster.The result by analytical electron microscopy indicated that iron, copper and sulphur were localized in granules of epithelial cells of the oyster gills. In contrast, these elements were not detected in other analytical points such as nuclei or cytoplasm.

Simultaneous determination of boron, phosphorus and sulphur in some biological and soil materials by inductively-coupled plasma emission spectrometry

Atomic emission lines at 249.678 nm, 214.911 nm and 180.735 nm are used simultaneously to determine total concentrations of boron, phosphorus and sulphur respectively, in plant and soil sample digests by means of inductively-coupled plasma emission spectrometry. The digestion procedures chosen enable these elements to be determined simultaneously on a single digest. Analytical data are compared after using various digestion procedures on standard reference materials. Actual and potential interelement interferences in the plasma are discussed together with attempts to overcome these interferences. Limitations for simultaneous determinations of boron, phosphorus and sulphur remain in the digestion and dissolution procedures.

Determination of 14 elements in botanical samples by simultaneous inductively coupled plasma atomic emission spectrometry using standard reference material as multielement standard

This paper describes the method, in which NBS (National Bureau of Standards) SRM 1571 (Standard Reference Material, Orchard Leaves) was used as multielement standard to determine 14 elements including major, minor and trace elements in 2 NBS and 3 BCR (Community Bureau of Reference of the European Communities) botanical Standard Reference Materials by simultaneous ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy). Very good agreement between the results and the certified values or information data for 11 elements was found. The low values for Al, Ti and Fe were due to incomplete digestion (extraction inefficiency) by pressure ashing with nitric acid. But these three values can be regarded as the nitric acid soluble portion. The interelement interferences caused by the major components such as Ca, Mg, Al, Mn and Fe were discussed and corrected. The paired digestion solutions of NBS SRM 1571 were also used as quality control standards. Accurate and reliable analytical results can be obtained by this method.

The determination of minor elements in steel by proton-induced prompt gamma-ray spectrometry

Pure elemental targets of Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo and W were irradiated with protons from 3.5 to 6.0 MeV, interference-free sensitivities were calculated for analysis by prompt gamma-ray spectrometry and sensitivity curves were plotted to show the variation of sensitivity with bombarding energy. Appropriate bombarding energies were selected for analysis and the extent of possible inter-element interferences and background effects were determined. Standard reference steels were used to evaluate this method for the determination of the minor elements Si, V, Cr, Mn and Co.

Back-extraction of trace elements from organometallic-halide extracts for determination by flameless atomic absorption spectrometry

The Methyl isobutyl ketone-Amine synerGistic Iodide Complex (MAGIC) extraction system offers the advantage that a large number of trace elements can be rapidly determined with a single sample preparation procedure. However, many of the elements extracted by the MAGIC system form volatile organometallic halide salts when the organic extract is heated in the graphite furnace. High concentrations of some elements such as Cu and Zn extracted by the system from anomalous geological samples produce serious interferences when certain other elements are determined by flameless atomic absorption. Stripping systems have been developed using solutions of HNO/sub 3/, H/sub 2/SO/sub 4/, and CH/sub 3/COOH individually or combined with H/sub 2/O/sub 2/ in order to circumvent these problems. With these systems most of the elements in the organic extract can be sequentially stripped into an aqueous phase. Organometallic volatilization and the most serious interelement interferences, therefore, can be eliminated by stripping with various combinations of reagents in a series of steps.

Elemental analysis by neutron inelastic scatter gamma rays with a radioisotope neutron source

The measurement of prompt γ-rays from neutron inelastic scattering is a promising technique for the bulk analysis of samples in the mineral industry. Applications will probably involve the use of radioisotope neutron sources and scintillation detectors. With scintillation detectors, it is important to be able to predict the effect of inter-element interferences. The photopeak intensities of 81 γ-rays from 21 elements have been measured using a Ge(Li) detector and 238Pu-Be source. These intensities have been used to calculate the photopeak intensities in the more industrially suitable NaI(Tl) detectors. The calculated NaI(Tl) photopeak intensities have been checked by measurement on prominent γ-rays from some elements. Examples are given of the applications of the present data to the prediction of γ-ray yields, and inter-element interferences in potential industrial applications. The technique is best suited to the analysis of elements of concentration >1 wt. % and preferable >5 wt. % in samples of about 10–100 kg. Preliminary results are presented of the application of the neutron inelastic scattering technique to the analysis of Pb/Zn ores.

Simultaneous determination of metals in oil by inductively coupled plasma emission spectrometry

The inductively coupled plasma in combination with a direct reading spectrometer has been used for the simultaneous determination of metals in oil to the sub ppM level. The instrument analysis time of about 1 minute per sample plus an efficient sample preparation scheme give the rapid results needed for the analysis of used oils for wear metals, for the characterization of crudes and feedstocks, and for monitoring of developmental processes. Instrument parameters and a simplified sample preparation technique are discussed. The few interelement interferences encountered are computer corrected, and the effects of a detergent and of an easily ionized element are found to be negligble. 6 tables, 2 figures.

Decomposition and determination of aluminium and silicon in Venezuelan laterites by atomic absorption spectroscopy

For the determination of alumina and silica in Venezuelan laterites by atomic absorption spectroscopy, the inter-element (chemical) interferences by the major common elements are eliminated by the fluoboric—boric acid matrix. The HF 3H 3BO 3 matrix also greatly increases the absorption signal for silicon relative to a water system. This method is shown to be precise and accurate when compared with reference rock materials. The Venezuelan laterites were also analyzed by an X-ray fluorescence technique for comparison.

Determination of low amounts of strontium in geological materials by flameless atomic absorption spectrophotometry

The analytical problem of the determination of trace amounts of strontium by flameless AAS in the graphite tube is examined. Inter-element interferences are of great significance. Reliable determinations of Sr in complex geological materials with very low contents in Sr, such as micas, can be achieved without separations by using standards with matrix compositions close to those of the samples.

Determination of acid-soluble and total rhodium on alumina-supported catalysts

Characterization of alumina-supported catalysts required determination of rhodium by atomic-absorption spectroscopy (AAS). Catalysts were loaded with 0.1–2.0% rhodium chloride and calcined at 400°. Rhodium remaining as the chloride was regarded as the soluble form, while that converted into the oxide or bonded to the alumina was regarded as the bonded form. By selective dissolution procedures, soluble rhodium was leached from the substrate and determined by AAS. Total rhodium was determined after the catalyst had been fused with sodium peroxide. Bonded rhodium can be determined by difference or by analysing leached residue. Optimization of AAS conditions, use of spectroscopic buffer solution and elimination of interelement interferences are discussed.

The determination of aluminium, iron, manganese and silicon in acid oxalate oil extracts by flame emission and atomic absorption spectrometry

A method for the analysis of single dilutions of acid oxalate extracts of soils for aluminium, iron and manganese by flame emission spectrometry and silicon by atomic absorption spectrometry is presented and compared with established methods. The effects of inter-element interferences are investigated, and an interference by oxalate and caesium on iron which is overcome when aluminium is present is discussed. Good agreement between the proposed and established methods is shown, and advantages in sensitivity, linearity of calibration, convenience and economy for the proposed method are also discussed.

General method for analysis of siliceous materials by atomic-absorption spectrophotometry and its application to macro- and micro-samples

The method described can be used for the dissolution and determination of major and minor constituents in a wide range of compositions of siliceous materials. A pressure dissolution vessel is used for fast and complete acid attack. The principle solvent is hydrofluoric acid, but boric acid is added after dissolution to complex excess of hydrofluoric acid and dissolve precipitated fluorides. A second heating step is shown greatly to improve the efficiency of this process.Most inter-element interferences are removed in the presence of the fluoroboric acid so formed when the dinitrogen oxide-acetylene flame is used. Neither releasing agents such as lanthanum nor detailed matching of standards to sample compositions are therefore necessary. Both macro- and micro-scale versions of the method are given, the latter having proved satisfactory for samples as small as 10 mg, such as those commonly encountered in archaeological work.

The determination of tellurium in leaded free-cutting steels by atomic-absorption spectrometry

A procedure is presented for the determination of tellurium within the range 0·005–0·08 per cent., with solvent conditions that permit its incorporation in a composite scheme that includes lead. In the preferred fuel-rich flame the background absorbance of iron and inter-element interferences are at a minimum.Good recoveries of tellurium when added to solutions of leaded and stainless steels, together with satisfactory reproducibilities for samples and good agreements with results by the slower turbidimetric procedure, are shown.

Studies of an inductively-coupled high-frequency argon plasma for optical emisson spectrometry—II: Compromise conditions for simultaneous multielement analysis

This paper deals with the experimental selection of conditions under which a low-power inductively-coupled plasma (ICP) can be operated so as to achieve a good compromise for simultaneous multi-element analysis. With the experimental facilities employed by the authors such conditions were found at a power of 0·7 kW, a carrier gas flow of 1·31 min of argon, and an observation height of 15 mm. An outstanding detection power with detection limits below 1 ng ml for 27 out of 32 representative elements and satisfactory suppression of ionization interference effects were simultaneously achieved. Modifications of a previously described ultrasonic nebulizer led to a higher rate of sample injection into the plasma, an improved overall reliability of the sample introduction device, and better reproducibility of spectral-line intensities (1·0–1·2% at concentrations 100 times the detection limits for 15-s integrations). Details of the construction of the ultrasonic nebulizer and its performance are provided and a simple theoretical treatment of the dependence of the aerosol ejection rate on the carrier gas flow and the size of the fog chamber is presented. Possible interelement interferences in the ICP are broadly classified. From the optimization experiments and application studies general conclusions regarding the usefulness of the ICP for both the accurate determination of a few elements and general overall analysis comprising a large number of elements are drawn.

Determination of ruthenium and iridium in anode coatings by atomic-absorption spectroscopy

A method is described for the determination of ruthenium and iridium coated on an electrode surface. The coating is chemically removed from the electrode by fusion with alkali, and the resulting solution prepared for analysis. Interelement interferences are eliminated by using a titanium-potassium matrix solution as a releasing agent. Recovery and precision data are given for ruthenium and iridium. The AAS determination of ruthenium compares favourably with a standard colorimetric method.