Interelement Interferences Research Articles

A New Method for Finding the Limits of Quantification of Elements, Estimating Dynamic Range, and Detecting Matrix and Interelement Interferences in Spectral Analysis (Atomic Absorption Spectrometry and ICP Analysis Methods)

A New Method for Finding the Limits of Quantification of Elements, Estimating Dynamic Range, and Detecting Matrix and Interelement Interferences in Spectral Analysis (Atomic Absorption Spectrometry and ICP Analysis Methods)

The determination of phosphate in rocks and iron ores using inductively coupled plasma with optical emission spectroscopy (ICP-OES)

Phosphate is a minor but important constituent of iron ores and is especially undesirable in the production of steel where it is considered a penalty element and is therefore tightly controlled. Iron ore quality must be determined at source, which means that deleterious elements must be accurately determined as an ongoing process. This demands fast, reliable analytical methods for the determination of, amongst others, phosphorus. However, such analysis is severely hampered by the following factors: the standard analytical method employed is X-ray fluorescence (XRF), but the measurements for phosphorus are seriously affected by matrix and inter-element interferences. An alternative technique is inductively coupled plasma with optical emission spectroscopy (ICP-OES), but there are also complications in using ICP-OES. The abundance of phosphorus in rocks is very low, generally under 0.5% wt. ICP-OES is also very insensitive to phosphorus and therefore must use the most sensitive spectral lines for quantification, and, there are serious spectral interferences on these lines by Fe and Cu. This study examines several analytical approaches for the determination of phosphate, using preparation by fusion and analysis by ICP-OES, demonstrating that suitable mathematical procedures and software applications can produce good results for phosphates, comparable to inter-laboratory tests or XRF.

Determination of Arsenic by Hydride Generation—Laser-Induced Breakdown Spectroscopy: Characterization of Interelement Interferences

ABSTRACTIn this study, interelement interferences were evaluated for the determination of arsenic in aqueous samples through laser-induced breakdown spectroscopy (LIBS) hyphenated with a hydride generation sample introduction system. Optimum instrumental and chemical parameters were selected and variation in LIBS signal intensity was recorded for As solution in the presence of comparable concentrations of interfering elements. No significant change in the signal intensity of As(I) 228.8 nm line was observed in the presence of alkali/alkali earth metals; however, the presence of hydride-forming elements has shown a noticeable decrease in the line emission strength of arsenic. The least variation in arsenic signal was observed in the presence of Ge, the most volatile of all. However, the signal has decreased to a greater extent in the presence of Sn, Sb, and Pb. The presence of interfering elements on electron temperature and electron number density of arsenic plasma has also been studied. Plasma temperatures calculated using both As and Ar emission lines in the Boltzmann equation were similar, being around 5000 K. The McWhirter criterion for stationary and homogenous plasmas was utilized for the establishment of the local thermodynamic equilibrium under the plasma conditions studied. Applicability of the technique for multielemental analysis of water samples was tested through spiking experiments. Arsenic signal showed 26% decrease in the multielemental mixture solution. LIBS is among a few atomic spectroscopic techniques that facilitate rapid and simultaneous multielemental analysis without extensive sample preparation steps. However, the analytical performance of the technique still requires more serious efforts to compete with other conventional techniques for routine analysis of environmental samples.

Neutron activation autoradiography and scanning macro-XRF of Rembrandt van Rijn’s Susanna and the Elders (Gemäldegalerie Berlin): a comparison of two methods for imaging of historical paintings with elemental contrast

Imaging methods with elemental contrast are of great value for the investigation of historical paintings, as they allow for study of sub-surface layers that provide insight into a painting’s creation process. Two of the most important methods are neutron activation autoradiography (NAAR) and scanning macro-XRF (MA-XRF). Given the differences between these methods in the fundamental physical phenomena exploited, a theoretical comparison of their capabilities is difficult and until now a critical comparison of their use on the same painting is missing. In this paper, we present a study of Rembrandt van Rijn’s painting Susanna and the Elders from the Gemaldegalerie in Berlin employing both techniques. The painting features a considerable number of overpainted features and a wide range of pigments with different elemental tracers, including earth pigments (Mn/Fe), Azurite (Cu), lead white (Pb), vermilion (Hg) and smalt (Co, As). MA-XRF can detect all elements above Si (Z = 14), suffers from few spectral overlaps and can be performed in a few tens of hours in situ, i.e. in a museum. NAAR requires the stay of the painting at a research facility for several weeks, and inter-element interferences can be difficult to resolve. Also, only a limited number of elements contribute to the acquired autoradiographs, most notably Mn, Cu, As, Co, Hg and P. However, NAAR provides a higher lateral resolution and is less hindered by absorption in covering layers, which makes it the only method capable of visualizing P in lower paint layers.

Evaluation of a total reflection X-ray fluorescence spectrometer in the determination of arsenic and trace metals in environmental samples

ABSTRACT Suitability of the PicoTAX total reflection X-ray fluorescence (TXRF) spectrometer was studied for determination of As and trace metals in the Haveri Au-Cu sulphide mine tailings leached with aqua regia and in water affected by acid mine drainage. Results for 12 water and 16 tailings samples were compared with accredited methods, inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). Certified reference samples analysed were QC Metal LL from Eurofins A/S, and groundwater CRM 609 and lake sediment BCR-280R from the Institute for Reference Materials and Measurements (IRMM) of the European Commission. Approximate method detection limits (MDL) for water samples, based on reference sample analyses, are in the range of 20 μg l −1 for As, Cr, Pb and Zn and 5–10 μg l −1 for Co, Cu, Ni, V and Mn. MDLs for aqua regia leach, calculated using reagent blank values, were ≤20 (mg kg −1 ) for As, Co, Cr, Cu, Mn, Ni, V, and Zn. Random error of determination varied from 12 to 20 %. Inter-element interferences include: As and Pb on each other, and Fe on Cr and Co. Using the Mo anode of the X-ray tube excludes the determination of Cd, Mo, Nb, Tc and Zr. TXRF can be recommended merely as a preliminary technique for selecting samples.

Application of ICP-OES to the determination of CuIn1−xGaxSe2 thin films used as absorber materials in solar cell devices

CuIn(1-x)Ga(x)Se2 [CIGS; x=Ga/(In+Ga)] thin films are among of the best candidates as absorber materials for solar cell applications. The material quality and main properties of the polycrystalline absorber layer are critically influenced by deviations in the stoichiometry, particularly in the Cu/(In+Ga) atomic ratio. In this work a simple, sensitive and accurate method has been developed for the quantitative determination of these thin films by inductively coupled plasma optical emission spectrometry (ICP-OES). The proposed method involves an acid digestion of the samples to achieve the complete solubilization of CIGS, followed by the analytical determination by ICP-OES. A digestion procedure with 50% HNO3 alone or in the presence of 10% HCl was performed to dissolve those thin films deposited on glass or Mo-coated glass substrates, respectively. Two analytical lines were selected for each element (Cu 324.754 and 327.396 nm, Ga 294.364 and 417.206 nm, In 303.936 and 325.609 nm, Se 196.090 and 203.985 nm, and Mo 202.030 and 379.825 nm) and a study of spectral interferences was performed which showed them to be suitable, since they offered a high sensitivity and no significant inter-element interferences were detected. Detection limits for all elements at the selected lines were found to be appropriate for this kind of application, and the relative standard deviations were lower than 1.5% for all elements with the exception of Se (about 5%). The Cu/(In+Ga) atomic ratios obtained from the application of this method to CIGS thin films were consistent with the study of the structural and morphological properties by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Inter-element interferences in the determination of arsenic and antimony by hydride generation atomic absorption spectrometry with a quartz tube atomizer

The interferences between arsenic and antimony on each other during the hydride generation atomic absorption spectrometry (HGAAS) determination of arsenic and antimony using a quartz tube atomizer (QTA) were examined. In order to eliminate or reduce such interferences by selective heat decomposition of arsine and stibine, a Pyrex adsorption U-tube trap containing glass wool was placed between the drying tube and the quartz tube atomizer. Although at 250°C stibine decomposes and is held almost completely by the trap, arsine is also decomposed to an extent of 24% and, therefore, thermal decomposition is not useful to eliminate antimony interference on arsenic determination. The effect of coating the glass wool in the U-tube with antimony on the arsenic suppression of the antimony signal was studied. The results showed that the antimony coating in the U-tube could not hold arsenic effectively and its interference on the antimony signal could not be eliminated by this means. In the second part of the study, oxygen was supplied to the quartz tube atomizer during atomization in order to study the effect of supplying oxygen on the antimony signal and on the interference of arsenic in the antimony determination. Sensitivity was increased in the presence of oxygen and interferences of arsenic on antimony determination was decreased by about 10% when oxygen was supplied. It was also observed that the extent of interferences depended mainly on the interferent concentration rather than the analyte concentration.

Spectral interference in the determination of Ho, Tm and Ga as dopants in single crystals of potassium titanylphosphate by inductively coupled plasma atomic emission spectrometry

The present article discusses the spectral interferences affecting the determination of Ga, Ho and Tm as dopants in single crystals of potassium titanylphosphate (KTiOPO 4) by inductively coupled plasma atomic emission spectrometry (ICP-AES). The Q concept, as proposed by Boumans and Vrakking [Spectrochim. Acta Part B 43 (1988) 69] was used for this study, which covers: (a) spectral data for potassium, titanium and phosphorous as interferents (at a concentration of 4 mg/ml) in 400 pm wide spectral windows around the prominent lines of the analytes; (b) a database of Q values for line interferences ( Q I) and for wing interferences ( Q W); and (c) the interelement interferences in doubly doped crystals of KTP.

Interferences in the quartz tube atomizer during arsenic and antimony determination by hydride generation atomic absorption spectrometry

Interferences of some metals in the determination of arsenic by hydride generation atomic absorption spectrometry utilizing a quartz tube atomizer were studied. The atomizers were coated under vacuum with Ni, Au, Pd and Cr. The arsenic signal was almost totally suppressed by all the metal coatings and thus the interferences from metal ions in the determination of arsenic were attributed both to the carry over of the reaction mixture, as well as interferences in the hydride formation step. Inter-element interferences by arsenic and antimony on each other in the atomizer of the same system were also studied. When arsine and stibine reach the atomizer at the same time they suppress each other’s signals. The interference of arsenic on antimony was eliminated by simply separating arsine, which elutes first, from stibine using a simple gas chromatographic column (GC column). However, even when arsine and stibine are separated using the GC column, antimony is deposited in the quartz tube atomizer at the temperatures the quartz tube attains when heated in the air–acetylene flame, suppressing the arsenic signal in subsequent experiments. Therefore, directing of stibine outside of the atomizer, after elution of arsine from the GC column, was suggested for arsenic determination.

Reference material certification by prompt-gamma activation analysis

Neutron-capture prompt-gamma-ray activation analysis (PGAA) shares most of the virtues of instrumental neutron activation analysis (INAA) for reference material certification: highly penetrating probe and response radiation, simple physics, and few interelement interferences or matrix related non-linearities. PGAA complements INAA in determining a different suite of elements using the same tools: a neutron source and gamma-ray spectrometry. Several important elements that are difficult to measure by other techniques are measurable by PGAA, notably H, B, C, N, and S. A survey of published applications and NIST Standard Reference Material certification work shows over thirty different SRMs analyzed by PGAA, including biological materials (botanical and food), coal and fly ash, metals, and several other matrices.

A General Technique for Heteropolyanion Analysis Using Inductively Coupled Plasma-Atomic Emission Spectroscopy, Atomic Absorption Spectroscopy and Gravimetry

Abstract A method using ICP-AES for the quantitative analysis of B, Si, Ge, P and Mo and atomic absorption spectroscopy for Na in a series of heteropolytungstates is described. The two-step procedure involves estimating the W composition of the polytungstate by a classical method and use of an analyte solution of comparable W content to the standard solutions in ICP-AES and AAS. This procedure minimizes interelement interferences and offers comparable precision to classical procedures. The method is more general than has been previously reported for the ICP-AES of B, Si, Ge. P and Mo in heteropolyanion formulations. Estimations of the W content of heteropolyanions by this procedure were less successful. The limitations of the method are discussed.

Hydride generation flow injection using graphite furnace detection: emphasis on determination of tin

Hydride generation, (HG), using flow injection methods, (FI), provides an ideal way to separate the hydride-forming analytes from a large volume of matrix. By trapping the hydrides on a Pd-coated L'vov platform at low temperature, it can be shown that the full process is at least 80% efficient for As, Bi, Ge, Sb, Se, Sn and Te. While this work was not fully automated, the various functions were conducted on-line. This method has been tested for the determination of Sn in various samples. The Pd-treated stabilized temperature platform furnace, (STPF), was used for in situ trapping and atomization of the analyte. Integrated absorbances were used for the measurement of the analytical signal. The detection limit for Sn was 7 ng l for a 10-ml sample. The analytical precision was 3–5% RSD at 1 ng of Sn. Inter-element interferences were investigated. The method has been applied to the determination of Sn in NIST Steel, River Sediment, Orchard Leaves and Bovine Liver Standard Reference Materials.

New developments and final frontiers in inductively coupled plasma spectrometry. Plenary lecture

A number of areas of study are indicated which are important in furthering the application and capability of the inductively coupled plasma. Featured especially are the importance of overcoming matrix and inter-element interferences, the development of diagnostics to monitor instrument operation, the use of adaptive computer-based feedback control to optimize instruments and the introduction of intelligent sample processing. Examples are taken from the author's laboratory of ways in which new developments in instrumentation and understanding are permitting these frontiers to be conquered.

Determination of rare-earth elements, yttrium, scandium and hafnium using cation-exchange separation and inductively coupled plasma-atomic emission spectrometry

The determination of low levels of rare-earth elements (REE), Y, Sc and Hf in geological samples has been achieved using minor modifications to established ion-exchange procedures with subsequent analysis by inductively coupled plasma-atomic emission spectrometry (ICP-AES). A lithium metaborate fusion followed by dissolution in dilute hydrochloric acid was used to ensure complete sample decomposition. Sample solutions were loaded onto columns containing AG 50W-X 8® cation-exchange resin, and unwanted elements were removed using elution with 1.75 M HCI followed by 1.75 M HNO 3. Almost all potentially interfering elements were eliminated using this procedure (only Ba and Zr remaining), and residual inter-element interferences were easily corrected. By adding a small amount of oxalic acid to the 6 M HNO 3 eluant the Hf present in the sample was eluted with the REE, Y and Sc. Analytical data obtained by ICP-AES were judged to be sufficiently accurate and precise (± 5%) for most geochemical applications. Measured detection limits for Y, Sc and Hf were respectively 0.2, 0.1 and 0.2 μg g −1 in samples.

Matrix-independent separation of rare-earth elements and yttrium from geological materials using constant calcium content-oxalate precipitation and cation exchange for determination by high-resolution inductively coupled plasma atomic emission spectrometry (ICP-AES)

Inductively coupled plasma atomic emission spectrometry (ICP-AES) is a precise and accurate analytical technique for determination of rare-earth elements (REE) in geologic materials provided the REE are separated from matrix elements. The separation method reported here uses cation exchange following an oxalate precipitation separation. Oxalate precipitation separates REE and Y with Ca from other matrix elements. Calcium oxalate is an effective carrier for REE, but is much more effective for light and middle REE (LREE and MREE) than for heavy REE (HREE). Complete REE recovery (especially of HREE) requires a sufficiently high Ca content in the sample. The method used here is to bring each sample (1 g) up to a Ca content of 107 mg by addition of calcium carbonate prior to sample digestion. Subsequent ion exchange with a mixed resin gives complete recovery of REE and Y (and in some cases Sc) without modification for sample type because the salt load is constant no matter what the starting material. Analysis of nine REE, Y and Sc is carried out using a very high-resolution sequential scanning ICP-AES system. High resolution minimizes RE inter-element interferences, and use of mixed-element standards (mixed in geologic proportions) minimizes corrections, usually to a negligible level. Analyses of U.S.G.S. standard reference materials BHVO- 1, DNC- 1 and TLM- 1 compare well with published values for REE and Y. Recovery of Sc is apparently not always complete.

Optimum group selection in multi-radionuclide determinations

A possible way to quantify inter-isotope and inter-element interferences in high resolution gamma-ray spectroscopy is described and possible future developments outlined. The use of a version of simulated annealing and the Metropolis algorithm in finding optimum element groupings is described and some results from tests of this procedure are given.

Some atomic absorption hydride generation inter-element interference reduction studies utilizing ion exchange resins

Ion exchange resins were used to reduce interelement interferences during the hydride generation flame atomic absorption determination of arsenic and selenium. Commercially available resins provided a means to significantly reduce the interferent to analyte ratio for several of the interfering elements. The procedure was successfully applied to highly polluted environmental samples.

Determination of Arsenic and Selenium in Environmental and Agricultural Samples by Hydride Generation Atomic Absorption Spectrometry

Agricultural and environmental samples are digested with acid, and arsenic and selenium are determined using hydride generation atomic absorption spectrometry. Interelement interferences are eliminated by high acid concentrations or cation-exchange resins. Agreement with standard reference material is excellent. The technique is also applied to actual samples.

Nonspectroscopic interelement interferences in inductively coupled plasma mass spectrometry

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNonspectroscopic interelement interferences in inductively coupled plasma mass spectrometryGeorge R. Gillson, Donald J. Douglas, John E. Fulford, Kenneth W. Halligan, and Scott D. TannerCite this: Anal. Chem. 1988, 60, 14, 1472–1474Publication Date (Print):July 15, 1988Publication History Published online1 May 2002Published inissue 15 July 1988https://doi.org/10.1021/ac00165a024RIGHTS & PERMISSIONSArticle Views672Altmetric-Citations208LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (406 KB) Get e-Alerts Get e-Alerts

Matrix effects in the separation of rare earth elements, scandium, and yttrium and their determination by inductively coupled plasma optical emission spectrometry

Due to its sensitivity and reproducibility, inductively coupled plasma optical emission spectrometry (ICP-OES) has developed into a very promising technique in the determination of the rare-earth elements (REE), Sc, and Y. However, the changing composition of natural samples may cause severe problems during separation from concomitant elements (matrix elements). In this study a simplified version of REE separation from 8 major and 27 trace elements is proposed. Some major matrix elements, depending on their kind and quantity, cause a specific depression of recovery rates of light REE (LREE) during the ion exchange process. The separation characteristics of two similar resins are described. Some trace matrix elements are separated inadequately. This effect and the interference of matrix element residues after separation on the REE determination are quantified. Finally, some RE interelement interferences are described. The developed methods are verified by the analyses of reference materials.