Speciation of antimony(III) and antimony(V) in cell extracts by anion chromatography/inductively coupled plasma mass spectrometry

An analytical method for the separation and quantification of Sb(III) and Sb(V) using anion chromatography with ICP-MS is presented. The optimum conditions for the separation of the antimony species were established with 15 mmol/L nitric acid at pH 6 as eluent system on a PRP-X100 column. The retention times for antimony(V) and antimony(III) were 85 s and 300 s with detection limits of 0.06 microg/L and 0.29 microg/L, respectively. The proposed method was applied to cell extracts of Leishmania donovani, which were incubated with antimony(III) and antimony(V). Some metabolism seemed to occur within the cells.     

Speciation of V, Cr and Fe by capillary electrophoresis-bandpass reaction cell inductively coupled plasma mass spectrometry

Capillary electrophoresis-dynamic reaction cell inductively coupled plasma mass spectrometry (CE-DRC-ICP-MS) for the speciation of iron(III/II), vanadium(V/IV) and chromium(VI/III) is described. Two different CE migration modes were employed for separating the six metal ions using pre-capillary complexation. One is counter-electroosmotic mode in which iron(III/II) and vanadium(V/IV) ions were well separated using a 60 cm x 75 microm i.d. fused silica capillary. The voltage was set at +22 kV and a 15 mmol l(-1) tris(hydroxymethyl)aminomethane (Tris) buffer (pH 8.75) containing 0.5 mmol l(-1) ethylenediaminetetraacetic acid (EDTA) and 0.5 mmol l(-1) ortho-phenanthroline (phen) was used as the electrophoretic buffer. The other is co-electroosmotic mode in which chromium(VI/III) ions were well separated while the applied voltage was set at -22 kV and a 10 mmol l(-1) ammonium citrate buffer (pH 7.7) containing 0.5 mmol l(-1) diethylenetriaminepentaacetic acid (DTPA) and 0.01% polybrene was used as the electrophoretic buffer. The mass spectra were measured at m/z 51, 52 and 56 for V. Cr and Fe, respectively. The interfering polyatomic ions of 35Cl16O+, 40Ar12C+ and 40Ar16O+ on 51V+, 52Cr+ and 56Fe+ determination were reduced in intensity significantly by using NH3 as the reaction cell gas in the DRC. The detection limits were in the range of 0.1-0.5, 0.4-1.3 and 1.2-1.7 ng ml(-1) for V, Cr and Fe, respectively. Applications of the method for the speciation of V, Cr and Fe in wastewater were demonstrated. The recoveries were in the range of 92-120% for various species.     

Speciation of arsenic by ion chromatography inductively coupled plasma mass spectrometry using ammonium eluents

A method based on ion chromatography (IC) and inductively coupled plasma MS (ICP-MS) was developed for the speciation of arsenic in water and soil extracts. An anion-exchange column (G3154A/101) was used to separate As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) with excellent resolution. Various ammonium salts, including NH4H2PO4, (NH4)2HPO4, (NH4)2CO3, and NH4HCO3, were examined as eluents to reduce matrix interference from chloride and to solve clogging problems. The best arsenic speciation was obtained within 9 min with excellent resolution and without interference from high chloride concentrations using an eluent containing 7.5 mM (NH4)2HPO4 at pH 7.9. The detection limits for the target arsenic species ranged from 0.1 to 0.4 microg/L with direct injection of sample without matrix elimination. The proposed method was effectively demonstrated by determining arsenic species in contaminated waters and soils of Bangladesh.     

Speciation of arsenic compounds by coupling high-performance liquid chromatography with inductively coupled plasma mass spectrometry

There is considerable evidence that toxicity and physiological behavior of arsenic depends on its chemical forms. Arsenic speciation became therefore the subject of increasing interest in recent years. A sensitive method for the determination of arsenic species has been developed. The proposed procedure involves the use of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Six arsenic compounds were separated by anion-exchange chromatography with isocratic elution using tartaric acid as mobile phase with an elution order: arsenocholine, arsenobetaine, dimethylarsinic acid, methylarsonic acid, arsenous acid and arsenic acid. The chromatographic parameters affecting the separation of the arsenic species were optimized. Analytical characterization of the method has been realized with standard solutions. The detection limits for six arsenic compounds were from 0.04 to 0.6 g/L as As element. The repeatability (expressed by R.S.D) was better than 7% for all investigated compounds. The HPLC-ICP-MS system was successfully applied to the determination of arsenic compounds in environmental and biological samples in g/L level.     

Speciation of chromium in waste water using ion chromatography inductively coupled plasma mass spectrometry

Ion chromatography (IC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was systematically investigated for determining the speciation of chromium in environmental samples. Firstly, the stability of complexes formed by Cr(III) with various aminopolycarboxylic acids was studied by electrospray ionization mass spectrometry (ESI-MS). The results showed that [Cr(EDTA)]⁻ was stable in solution. Secondly, various mobile phases were examined to separate Cl⁻ from chromium species by IC to avoid Cl⁻ interference. The separation of [Cr(EDTA)]⁻ and Cr(VI) was achieved on a new anion-exchange column (G3154A/102) using a mobile phase containing 20 mM NH₄NO₃ and 10 mM NH₄H₂PO₄ at pH 7.0 without Cl⁻ interference. Detection limits for chromium species were below 0.2 μg/L with a direct injection of sample and without prior removal of interferences from the matrix. Finally, the proposed method was used for the determination of chromium species in contaminated waters.     

Speciation of iodate and iodide in seawater by non-suppressed ion chromatography with inductively coupled plasma mass spectrometry

A non-suppressed ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for simultaneous determination of trace iodate and iodide in seawater. An anion-exchange column (G3154A/101, provided by Agilent) was used for the separation of iodate and iodide with an eluent containing 20 mM NH₄NO₃ at pH 5.6, which reduced the build-up of salts on the sampler and skimmer cones. The influences of competing ion (NO₃⁻) in the eluent on the retention time and detection sensitivity were investigated to give reasonable resolution and detection limits. Linear plots were obtained in a concentration range of 5.0–500 μg/L and the detection limit was 1.5 μg/L for iodate and 2.0 μg/L for iodide. The proposed method was used to determinate iodate and iodide in seawaters without sample pre-treatment with exception of dilution.     

Speciation of arsenic(III) and arsenic(V) by inductively coupled plasma-atomic emission spectrometry coupled with preconcentration system

A novel and simple flow-based method was developed for the simultaneous determination of As(III) and As(V) in freshwater samples. Two miniature columns with a solid phase anion exchange resin, placed on two 6-way valves were utilized for the solid-phase collection/concentration of arsenic(III) and arsenic(V), respectively. As(III) could be retained on the column after its oxidation to As(V) species with an oxidizing agent. The collected analytes were then sequentially eluted by 2 M nitric acid and introduced into ICP-AES. Potassium permanganate was examined as potential oxidizing agent for conversion of As(III) to As(V). The standard deviation of the analytical signals (peak height) for the replicate analysis (n = 5) of 0.5 μg l⁻¹ solution were 3 and 5% for As(III) and As(V), respectively. The limit of detection (3σ) for both As(III) and As(V) were 0.1 μg l⁻¹. The proposed system produced satisfactory results on the application to the direct analysis of inorganic arsenic species in freshwater samples.     

Speciation of Zn‐aminopolycarboxylic complexes by electrospray ionization mass spectrometry and ion chromatography with inductively coupled plasma mass spectrometry

The speciation of Zn‐aminopolycarboxylic complexes was investigated using both electrospray ionization mass spectrometry (ESI‐MS) and ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP‐MS). The resulting ESI mass spectra indicated that [Zn(HEDTA)]^1?, [Zn(NTA)]^1?, [Zn(EDTA)]^2? and [Zn(DTPA)]^3? were all simultaneously detected in solution; [Zn(NTA)]^1? exhibited the weakest intensity of all these Zn‐aminopolycarboxylic complexes. IC/ICP‐MS was also successfully used to separate Zn complexes by anion‐exchange chromatography using a mobile phase containing 30 mM (NH₄)₂HPO₄ at pH 7.5 giving reasonable resolution within 15 min. A weak peak attributable to the poor stability [Zn(NTA)]^1? ion was also observed using IC/ICP‐MS. With the exception of [Zn(NTA)]^1?, detection limits ranging from 0.5 to 1.0 µg/L were obtained and the proposed method was used for the determination of Zn aminopolycarboxylic complexes in soil solution. Copyright © 2009 John Wiley & Sons, Ltd.     

Speciation of metal-EDTA complexes by flow injection analysis with electrospray ionization mass spectrometry and ion chromatography with inductively coupled plasma mass spectrometry

Flow injection analysis (FIA) with ESI-MS and ion chromatography (IC) with inductively coupled plasma-MS (ICP-MS) as the complementary technique have been explored for the determination of metal ions as their metal-EDTA complexes. ESI-MS enabled the identification of metal-EDTA complexes such as [Mn(EDTA)](2-), [Co(EDTA)](2-), [Ni(EDTA)](2-), [Cu(EDTA)](2-), [Zn(EDTA)](2-), [Pb(EDTA)](2-), and [Fe(EDTA)](1-) and their MS spectral showed that these metal-EDTA complexes were present in solution. Based on the ESI-MS, ion chromatographic separation and ICP-MS detection of these complexes are possible because IC-ICP-MS requires stable metal-EDTA complex during the chromatographic separation. The separation of these metal-EDTA complexes was achieved on an anion-exchange column with a mobile phase containing 30 mM NH(4)(HPO(4))(2) at pH 7.5 within 7 min with ICP-MS providing element specific detection. The ICP-MS LODs for the metal-EDTA were in the range of 0.1-0.5 microg/L with the exception of Fe (15 microg/L). The proposed method was a simple procedure for sample processing, using direct injection of sample without removal of sample matrix and was successfully applied to the determination of metal-EDTA complexes in real samples.     

Speciation of vanadium in oilsand coke and bacterial culture by high performance liquid chromatography inductively coupled plasma mass spectrometry

A simple and sensitive method for the speciation of vanadium(III), (IV), and (V) was developed by using high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICPMS). The EDTA-complexed vanadium species were separated on a strong anion exchange column with an eluent containing 2 mM EDTA, 3% acetonitrile, and 80 mM ammonium bicarbonate at pH 6. Each analysis was complete in 5 min. The detection limits were 0.6, 0.7 and 1.0 μg L⁻¹ for V(III), V(IV), and V(V), respectively. The method was applied to coke pore water samples from an oilsand processing/upgrading site in Fort McMurray, Alberta, Canada and to Shewanella putrefaciens CN32 bacterial cultures incubated with V(V). In the coke pore water samples, V(IV) and V(V) were found to be the major species. For the first time, V(III) was detected in the bacterial cultures incubated with V(V).     

Determination of antimony and tin in tin dioxide whiskers by inductively coupled plasma mass spectrometry

A procedure for the determination of antimony and tin in tin dioxide whiskers, which were grown from a gas phase by the vapor-liquid-solid mechanism, was developed. The problem was difficult because the single whiskers are irregularly small in size and have a small weight (about 10^?5 g). The procedure is based on the decomposition of a solid sample by cementation on zinc followed by the determination of analytes with the use of inductively coupled plasma mass spectrometry. The procedure developed is characterized by the detection limits of antimony of 0.01–0.03 μg/L and an RSD of 10%. An approach was proposed to estimate the antimony content of single whiskers.     

Neptunium determination by inductively coupled plasma mass spectrometry (ICP-MS)

The determination of neptunium-237 (²³⁷Np) traditionally has been performed by alpha spectrometry or neutron activation analysis. These methods are labor intensive and require several days for completion. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a possible alternative for²³⁷Np determinations. This paper describes the analytical method developed for samples that have significant levels of uranium present. The lower reporting limits achievable by ICP-MS are competitive with the counting methods, but the real advantage for this laboratory lies in the lower cost and faster turnaround time provided by ICP-MS.     

Speciation of cationic selenium compounds in Brassica juncea leaves by strong cation-exchange chromatography with inductively coupled plasma mass spectrometry

Strong cation-exchange chromatography (SCX-HPLC) was used in conjunction with inductively coupled plasma mass spectrometry (ICP-MS) to investigate cationic selenium species present in leaf extract of wild-type Brassica juncea supplemented with selenite. Total amount of Se accumulated by the leaves was found to be 352 microg g(-1). Cation-exchange solid-phase extraction (SCX-SPE) was used to pre-concentrate the cationic species present in the leaf extract. Methylselenomethionine (MeSeMet) and dimethylselenoniumproprionate (DMSeP) were synthesized and characterized by electrospray quadrupole time-of-flight MS (ESI-QTOF-MS). Laboratory synthesized and commercially available standards were used in chromatographic studies to identify the Se species in the leaf extract through retention time comparisons and standard addition method. Major cationic selenium species identified in the present study were MeSeMet and methylselenocysteine (MeSeCys) while selenomethionine (SeMet) was found in minor quantities.     

Speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts by ion chromatography with inductively coupled plasma mass spectrometry with an octopole reaction system

Ion-pairing chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) used for the speciation of phosphorus is limited as the mobile phase containing organic solvents changes in detection sensitivity and the carbon precipitates on torch and cones. To address this issue, anion-exchange chromatography with ICP-MS has been used for the speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts. The separation of the targets on a new column was achieved within 5 min using an eluent containing 20 mM NH₄NO₃ at pH 5.1. Furthermore, since the polyatomic ions such as ¹⁴N¹⁶O¹H⁺ and ¹⁵N¹⁶O⁺ from a nitrogen-based ion-pairing reagent interfered with ICP-MS detection of ³¹P, an octopole reaction system was investigated to determine whether the polyatomic interferences could be reduced. The results show that addition of He to the cell can benefit analyses by reducing such interferences, but at the expense of reduced sensitivity. The detection limits in the range of 1.0-1.5 μg L⁻¹ (expressed as P) was achieved when 50 μL was injected using He as the collusion gas.     

Determination of plutonium by inductively coupled plasma mass spectrometry (ICP-MS)

Inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the measurement of plutonium isotopes in soils. In the ICP-MS, a calibration curve method was conveniently utilized even in high viscosity solution using a Babington nebulizer. Plutonium concentrations in soil around the Kashiwazaki-Kariwa nuclear power station were found to be in the range of 0.054 to 1.0 Bq/kg with an average of 0.27 Bq/kg. The ratios of ²³⁹Pu/²⁴⁰Pu were also obtained with the ICP-MS to investigate the origin of Pu-isotopes. On the basis of this result, the origin of the Pu-isotopes was attributed to be fallout from the past atmospheric nuclear tests.     

Speciation of gadolinium in surface water samples and plants by hydrophilic interaction chromatography hyphenated with inductively coupled plasma mass spectrometry

Hydrophilic interaction chromatography (HILIC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was optimized for speciation analysis of gadolinium-based contrast agents in environmental samples, in particular surface river waters and plants. Surface water samples from the Teltow channel, near Berlin, were investigated over a distance of 5 km downstream from the influx of a wastewater treatment plant. The total concentration of gadolinium increased significantly from 50 to 990 ng?L^?1 due to the influx of the contrast agents. After complete mixing with the river water, the concentration remained constant over a distance of at least 4 km. Two main substances [Dotarem® (Gd-DOTA) and Gadovist® (Gd-BT-DO3A)] have been identified in the river water using standards. A gadolinium-based contrast agent, possibly Gd-DOTA (Dotarem®), was also detected in water plant samples taken from the Teltow channel. Therefore, uptake of contrast agents [Gadovist® (Gd-BTDO3A), Magnevist® (Gd-DTPA), Omniscan® (Gd-DTPA-BMA), Dotarem® (Gd-DOTA), and Multihance® (Gd-BOPTA)] by plants was investigated in a model experiment using Lepidium sativum (cress plants). HILIC–ICP-MS was used for identification of different contrast agents, and a first approach for quantification using aqueous standard solutions was tested. For speciation analysis, all investigated contrast agents could be extracted from the plant tissues with a recovery of about 54 % for Multihance® (Gd-BOPTA) up to 106 % for Gadovist® (Gd-BT-DO3A). These experiments demonstrate that all contrast agents investigated are transported from the roots to the leaves where the highest content was measured.     

Determination of inorganic arsenic(III) and arsenic(V) in water samples by ion chromatography/inductively coupled plasma-mass spectrometry

A method was validated for the direct determination of As(III) and As(V) in water samples by ion chromatography/inductively coupled plasma-mass spectrometry. Sample preservation required only dilution with a mobile phase containing a sufficient amount of ethylenediaminetetraacetic acid and acetic acid. Analyses of 6 certified reference materials (CRMs) of various water matrixes, including seawater, demonstrated good method accuracy. The matrixes included 2 natural water samples [National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1643e and NIST SRM 1640], 1 fortified standard solution (TMDA-64), 1 fortified water sample (TM-DWS), and 2 seawater samples (CASS-4 and NASS-5). The sum of As(III) and As(V) in each CRM agreed with the respective certified value for the total amount of As within its stated uncertainty. Quantitative recoveries (96.7-102.1%) were obtained. Satisfactory results were achieved for intraday repeatability [relative standard deviation (RSD = 0.3-5.1%] and interday precision (RSD = 0.7-4.1%). In the study of fortified blanks and fortified CRMs, quantitative recoveries of As(III) and As(V) (92.5-102.6%) were obtained. Interconversion of As(III) and As(V) was not observed under the conditions of sample preservation. International comparability of analytical results was demonstrated by the analysis of 2 interlaboratory proficiency test samples, NY7011 and NY8511, from the New York State Department of Health.     

Determination of vanadium by reaction cell inductively coupled plasma mass spectrometry

Recent advances in inductively coupled plasma mass spectrometry (ICP-MS) have included the addition of interference reduction technologies, such as collision and reaction cells, to improve its detection capability for certain elements that suffer from polyatomic interferences. The principle behind reaction cell (RC)-ICP-MS is to remove a particular polyatomic interference by dissociation or formation of a different polyatomic species that no longer interferes with the analyte of interest. However, some interferences cannot be removed by commonly reported reaction gases, such as hydrogen, oxygen, or methane, necessitating using more reactive and hazardous gases, such as ammonia. The current study investigates oxygen as a reaction gas in RC-ICP-MS to specifically react with vanadium analyte ions, rather than the interferents, to produce a polyatomic analyte species and thereby provide a way to analyze for vanadium in complex environmental matrices. The technique has been tested on a series of river water, tap water, and synthetic laboratory samples, and shown to be successful in vanadium analyses in high chloride and sulfate matrices. The zinc isobaric interference on the new vanadium oxide analyte at m/z 67 is also investigated, and can be corrected by using a standard mathematical correction equation. The results of this study further increase the utility of RC-ICP-MS analytical techniques for complex environmental matrices.     

Applications of inductively coupled plasma mass spectrometry and laser ablation inductively coupled plasma mass spectrometry in materials science

Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) have been applied as the most important inorganic mass spectrometric techniques having multielemental capability for the characterization of solid samples in materials science. ICP-MS is used for the sensitive determination of trace and ultratrace elements in digested solutions of solid samples or of process chemicals (ultrapure water, acids and organic solutions) for the semiconductor industry with detection limits down to sub-picogram per liter levels. Whereas ICP-MS on solid samples (e.g. high-purity ceramics) sometimes requires time-consuming sample preparation for its application in materials science, and the risk of contamination is a serious drawback, a fast, direct determination of trace elements in solid materials without any sample preparation by LA-ICP-MS is possible. The detection limits for the direct analysis of solid samples by LA-ICP-MS have been determined for many elements down to the nanogram per gram range. A deterioration of detection limits was observed for elements where interferences with polyatomic ions occur. The inherent interference problem can often be solved by applying a double-focusing sector field mass spectrometer at higher mass resolution or by collision-induced reactions of polyatomic ions with a collision gas using an ICP-MS fitted with collision cell. The main problem of LA-ICP-MS is quantification if no suitable standard reference materials with a similar matrix composition are available. The calibration problem in LA-ICP-MS can be solved using on-line solution-based calibration, and different procedures, such as external calibration and standard addition, have been discussed with respect to their application in materials science. The application of isotope dilution in solution-based calibration for trace metal determination in small amounts of noble metals has been developed as a new calibration strategy. This review discusses new analytical developments and possible applications of ICP-MS and LA-ICP-MS for the quantitative determination of trace elements and in surface analysis for materials science.     

Speciation of seleno compounds in yeast aqueous extracts by three-dimensional liquid chromatography with inductively coupled plasma mass spectrometric and electrospray mass spectrometric detection

A three-dimensional liquid chromatographic purification protocol based on sequential size-exclusion, anion-exchange and cation-exchange separation mechanisms was developed for the mapping of seleno compounds in aqueous yeast extracts. The method allowed the demonstration of the presence of more than 30 different seleno compounds. Semi-preparative size-exclusion and anion-exchange chromatography were optimized for maximum resolution using electrospray-compatible buffers in order to purify the compounds for mass spectrometric analysis. Molecular masses were attributed to many of the compounds on the basis of the selenium isotopic pattern in the electrospray mass spectra and of the collision-induced fragmentation patterns. Limitations preventing the ultimate identification of the selenium species detected are discussed.