Quadrupole Inductively Coupled Plasma Mass Spectrometer Research Articles

Optimization of lithium isotope analysis in geological materials by quadrupole ICP-MS

This study develops and optimizes a new method to measure lithium isotope ratios using a single collector quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) operated under hot plasma (1550 W) conditions.

Rapid detection of enriched uranium in food

We have developed a quadrupole ICP-MS method for detecting sub-picogram quantities of 235U in contaminated foods. Notable features included elimination of the requirement for possessing licensed nuclear materials so that non-radiochemical laboratories may perform this analysis in the event of a large-scale nuclear or radiological emergency calling for high sample surge capacity, elimination of several extremely hazardous reagents in sample analysis e.g. aqua regia and hydrofluoric acid, and the method was developed for applying a moderately priced, and widely used quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS). This method could be quickly implemented at many laboratories to increase emergency response capability.

An improved matrix separation method for characterization of ultrapure germanium (8N)

An improved matrix separation method has been described to characterize ultrapure germanium of 8N (99.999999%) purity. In this method, temperature of the reaction vessel in which in-situ generated chlorine gas reacts with germanium solid material directly is optimized to quantitatively remove Ge matrix from all its impurities. Optimized reaction temperature has been found to be 230±5°C. Recovery studies on more than 60 elements have been carried out at the optimized temperature. Recoveries of all the analytes except As, Se, Sn, Hg, Tl are found to be quantitative. The method has been examined for various amounts of Ge material and found to be suitable even for 10g of Ge sample and provides low parts per billion and trillion levels of process blanks. Determination of concentrations of impurities has been done by inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and high resolution continuum source graphite furnace atomic absorption spectrometer (HR-CS-GFAAS). In the absence of certified reference materials for ultrapure germanium, accuracy of the proposed method is established by spike recovery tests. Precision of this method is found to vary from 7% to 50% for concentrations between 4 and 0.004ngg−1. Limits of detection (LOD) for the target analytes are found to be between 6 and 0.011ngmL−1 or 1.8–0.003ngg−1 for the proposed procedure. The method has been successfully applied for that characterization of ultrapure germanium material of 8N purity.

Isotopic and chemical analysis of gadolinium oxide nuclear grade

Natural gadolinium oxide is added in nuclear fuels of compact design reactors to control the power mainly on the start of operation, as neutronic poison. Gadolinium has a high neutron absorption cross section (σγ). All Gd isotopes have significant σγ, specially 155 and 157 (60,900 and 254,000b (10−24cm2), respectively). It is important the isotopic and chemistry purity of the nuclear fuels materials to avoid the generation of unwished radioactive elements or extra neutron poisons. Main possible impurities that could be presented are the rest of Rare Earths (REEs) like Eu, Sm, Tb, Yb, and Dy. The objective of the present contribution was to develop methods for the certification of isotopic composition in natural nuclear grade Gd2O3 and also to determine the content of REE impurities. Two methodologies were explored for isotopic analysis by Thermal Ionization Mass Spectrometry (TIMS): Total Evaporation (TE) and Conventional Analysis (CA). Results are comparable with both methodologies, although CA uncertainties are better. The analysis of impurities was performed with a Quadrupole Inductively Coupled Plasma Mass Spectrometer (Q-ICPMS). Concentration of different REEs is in agreement with certificate of supplier and nuclear specifications.

Modified matrix volatilization setup for characterization of high purity germanium

Modified matrix volatilization (MV) method has been described to characterize high purity germanium material of 7N (99.99999%) purity. Transport of both, the chlorine gas generated in-situ in this method and the argon gas (carrier) is fine controlled by means of a mass flow controller. This enabled both uniform reaction of chlorine gas with the germanium matrix and smooth removal of germanium matrix as its chloride. This resulted in improvement in the reproducibility of the analytical results. The use of quartz reaction vessel has lead to the reduction in the process blank levels. The combined effect of these modifications in the MV setup has resulted in very consistent and low process blanks and hence improved detection limits of this method. Applicability of the method has been expanded to rare earth elements and other elements after examining their recoveries. The quantification is done by using inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and continuum source graphite furnace atomic absorption spectrometry (CS-GFAAS). In the absence of certified reference materials for high pure germanium, the accuracy of the method is established by spike recovery tests. The precision of the method has been found to vary from 1 to 30% for concentrations between 1 and 30ngg−1. The limits of detection (LOD) for the target analytes are found to be between 18 and 0.033ngg−1.

Measurement of 238 U/ 235 U ratio in black spruce seedlings to fingerprint the source of uranium taken up by black spruce trees as a biogeochemical sampling medium

This study explored the measurement of 238 U/ 235 U ratios in black spruce seedlings as a tracer to investigate the origin of U taken up by this biogeochemical sampling media. Inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and neutron activation (NAA) analyses of the 238 U/ 235 U ratios in the total digested (HF/HNO 3 -aqua regia) portions of substrates (soil and peat) treated with 200 ml aliquots of 100, 250, and 400 mg/l of aqueous solutions of depleted uranium (DU) exhibited a substantial deviation from the accepted natural value of 137.88. Similarly, the measured 238 U/ 235 U ratios in stems of seedlings grown in the DU-dosed substrates ranged from 174 to 210 and are linearly correlated with the dose of DU applied. The elevated 238 U/ 235 U ratio in the seedlings suggests that U taken up by the plants is derived predominantly from the labile DU components in water rather than the component adsorbed onto mineral phases in the substrate. Consequently, it was concluded that the U contents in vegetation used as a biogeochemical sampling medium are derived from the labile components in groundwater and/or surface water. The precision and accuracy of the measured ratios were compared with the 238 U/ 235 U ratios of in-house granite and uraninite reference samples.

In situ location and U‐Pb dating of small zircon grains in igneous rocks using laser ablation–inductively coupled plasma–quadrupole mass spectrometry

A new U‐Pb zircon dating protocol for small (10–50 μm) zircons has been developed using an automated searching method to locate zircon grains in a polished rock mount. The scanning electron microscope‐energy‐dispersive X ray spectrum‐based automated searching method can routinely find in situ zircon grains larger than 5 μm across. A selection of these grains was ablated using a 10 μm laser spot and analyzed in an inductively coupled plasma‐quadrupole mass spectrometer (ICP‐QMS). The technique has lower precision (∼6% uncertainty at 95% confidence on individual spot analyses) than typical laser ablation ICP‐MS (∼2%), secondary ion mass spectrometry (<1%), and isotope dilution‐thermal ionization mass spectrometry (∼0.4%) methods. However, it is accurate and has been used successfully on fine‐grained lithologies, including mafic rocks from island arcs, ocean basins, and ophiolites, which have traditionally been considered devoid of dateable zircons. This technique is particularly well suited for medium‐ to fine‐grained mafic volcanic rocks where zircon separation is challenging and can also be used to date rocks where only small amounts of sample are available (clasts, xenoliths, dredge rocks). The most significant problem with dating small in situ zircon grains is Pb loss. In our study, many of the small zircons analyzed have high U contents, and the isotopic compositions of these grains are consistent with Pb loss resulting from internal α radiation damage. This problem is not significant in very young rocks and can be minimized in older rocks by avoiding high‐U zircon grains.

Behaviour of arsenic and selenium in an ICP-QMS with collision and reaction interface

The performance of a collision reaction interface (CRI) for minimization of spectral interferences on analytical signals of 75As+ and 76Se+, 77Se+, 78Se+, 80Se+ and 82Se+ isotopes was evaluated by using H2 and He gases introduced through the sampler or skimmer cones of an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS). Different gas flow rates were tested employing reference solutions prepared either in hydrochloric acid or in water soluble tertiary amines (CFA-C) media as carbon source. A hydrogen gas flow rate at 60 mL min−1 introduced through skimmer cone was effective for minimizing polyatomic interferences on 75As+ and Se isotopes, except for 80Se+. The use of He introduced through sampler or skimmer cones had a minor effect on the minimization of interferences when compared to the use of H2 gas. Moreover, it was observed that the gas introduction through the sampler cone had no effect on interferences when using gas flow rates up to 80 mL min−1 for both gases evaluated. Based on these results, it can be recommended to use H2 gas introduced through skimmer cone of the CRI for correcting polyatomic interferences on 75As+ and Se isotopes in matrixes containing up to 2% v v−1 chloride.

Interlaboratory Comparison for Boron Isotope Ratio Measurement with Inductively Coupled Plasma - Quadrupole Mass Spectrometer

Boron isotope ratios were analyzed in seven domestic analytical labs for boric acid solutions with various compositions of boron isotope abundances, using an Inductively Coupled Plasma–Quadrupole Mass Spectrometer (ICP-QMS). Five sample solutions with different isotope abundances of 10B were prepared in the range of 10 to 20% by mixing two boric acid solutions containing natural B and enriched 11B, respectively. Then, the 10B isotope abundances of each sample were certified by analyzing with thermal ionization mass spectrometry (TI-MS) according to ASTM-C791-04. Results obtained from each lab have indicated good coincidences with TI-MS results. Also, the relative standard deviations of results with ICP-QMS of seven analytical labs were 0.11 to 0.81%. The measurement precision for ICP-QMS would be sufficient in terms of practical use, while taking into consideration a valid requirement required for verifying a depletion of the 10B isotope abundance in the PWR coolant, while this is greater than a nominal analytical error (relative value : 0.22%) for TI-MS shown in ASTM-C791-04.

Ethnoarchaeological analysis of Arctic fish processing: chemical characterization of soils on Nelson Island, Alaska

Activity area analysis of archaeological soils using multi-element characterizations can illuminate how subsistence operations are organized and how subsistence behavior has changed over time, and is increasingly common at archaeological sites. However, in many regions it is impossible to examine the elemental signatures in known anthropogenic soil samples in order to compare them with unknown archaeological samples. This ethnoarchaeological study examines the chemical composition of the soils at known fish processing areas in the contemporary community of Tununak on Nelson Island, western Alaska. Using a quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS), the concentrations of the following elements in the soil extract were recorded in parts per million (ppm): aluminum (Al), barium (Ba), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), strontium (Sr), titanium (Ti), and zinc (Zn). Fish processing area features are elevated in various elements, including sodium, magnesium, phosphorus, potassium, and manganese, and Ba/Sr, Ba/Ca, and Sr/Ca are also useful in distinguishing between fish processing areas and offsite areas.

Molybdenum Speciation in Raw Phloem Sap of Castor Bean

Separation and quantification of molybdenum (Mo) in raw phloem sap from castor bean (Ricinus communis L.) was performed by size exclusion chromatography (SEC) and further purification was performed using quantitative preparative native continuous polyacrylamide gel electrophoresis (QPNC-PAGE). For elemental detection, an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) was applied. Two different SEC columns were utilized: column A, Sephadex G-50 SF (700 mm × 24 mm), and column B, Sephadex G-25 M (28 mm × 9 mm). The protein content of the fractions was determined by the Bradford method. Using column A, two peaks of Mo were detected consisting of a main peak (MoA2) in the low molecular weight area (< 1.35 kDa), and a minor peak (MoA1, ≥ 30 kDa) at the void volume of the column. Both Mo species were detected at the ultraviolet (UV) active absorption area of raw phloem sap. Two peaks of Mo were also detected using column B, the first peak (MoB1) being at the same elution volume as the protein of raw phloem sap, and the second one (MoB2) was eluted in the area of 1.5 to 2.4 mL of elution volume. Raw phloem sap digested by proteinase K-enzyme indicates a significant reduction of MoB1 peak, which suggests that the peak may contain Mo bound to protein or polypeptides. The raw phloem sap and SEC fraction containing highest Mo concentration (MoA2) were furthermore separated by QPNC-PAGE. The result reveals that the Mo-containing fraction from the raw phloem sap was eluted at the same retention volume as the purified sample. This implies that the Mo species were also successfully separated and purified using QPNC-PAGE.

Revisiting type-A uncertainties relating to the measurement of mass fraction of lead using isotope-dilution inductively coupled plasma mass spectrometry: a way of improving measurement precision and expanded uncertainty

A quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) has been used for determination of lead in plant materials using isotope-dilution inductively coupled plasma mass spectrometry. The accuracy of the method was demonstrated by analysis of a matrix certified reference material, NIST SRM 1547 Peach Leaves. Specific instrumental parameters of Q-ICP-MS, including isotope analysis mode, integration time per point, number of points per mass, and number of measurements, were optimized to obtain the best measurement precision. The precision (expressed as relative standard deviation) associated with replicate measurement of the 208Pb/206Pb isotope ratio and its mass-bias correction factor was <0.2%. Following “Example A7” of the Eurachem/CITAC Guide, the relative expanded uncertainty, U rel, (coverage factor k = 2) was found to be ±1.1%, which fulfilled the target value of ±2% maximum and was lower than the uncertainty of ±3.4% reported by NIST based on isotope-dilution thermal ionization mass spectrometry. Sample recovery of 99% was obtained.

High precision measurements of Mg/Ca and Sr/Ca ratios in carbonates by cold plasma inductively coupled plasma quadrupole mass spectrometry

We present a new high precision analytical method for the determination of Mg/Ca and Sr/Ca ratios in carbonates using an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) with a 650-W cold plasma technique and a desolvation introduction system. Signal intensities are detected in pulse-counting mode and Mg/Ca and Sr/Ca ratios are calculated directly from intensity ratios of 24Mg/ 43Ca and 86Sr/ 43Ca using external matrix-matched standards for every 4–5 samples to correct for instrumental mass discrimination and low-frequency ratio drift. Significant matrix effect of Ca content on Mg/Ca determination (− 0.018 Mg/Ca (mmol/mol)/[Ca] (ppm)), can be overcome by diluting [Ca] to 6–8 ppm in the sample solution or using an empirical correction. The Sr/Ca ratio affects the Mg/Ca determination, with a factor of − 0.32% Mg/Ca per mmol/mol. This is mainly caused by the influence of doubly charged 86Sr, which biases the intensity measurement of the 43Ca + ion beam. This effect results in a trivial offset of less than 0.1% on Mg/Ca measurements for Quaternary foraminiferal and coral samples. The internal precision of our method ranges from 0.1 to 0.2%. Replicate measurements made on standards and samples show long-term external uncertainties (2σ) of Mg/Ca = 0.84% and Sr/Ca = 0.49%. The minimum sample size requirement is only 3.5 μg of carbonate. The application of this newly developed technique on the planktonic foraminifera Globigerinoides ruber from a core recovered in the southern South China Sea yields a glacial–interglacial difference in sea surface temperature (SST) of 3 °C. Three-year coral Sr/Ca data suggest that the seasonal SST ranged from 22.6–23.8 °C in winter to 26.9–27.9 °C in summer in Nanwan, south Taiwan, during 2000–2002. The coral-Sr/Ca inferred SSTs in 2002 match well with instrumental records, which demonstrates the validity of this ICP-QMS method.

Simultaneous quantification of 17 trace elements in blood by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) equipped with a high-efficiency sample introduction system

A quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) equipped with a dynamic reaction cell (DRC) and coupled with a desolvating nebulization system (APEX-IR) was employed to determine 17 elements (Al, As, Ba, Cd, Co, Cr, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, V, and Zr) in blood samples. Ammonia (for Al, Cr, Mn, and V) and O 2 (for As and Se) were used as reacting gases. Selection of the best flow rate of the gases and optimization of the quadrupole dynamic bandpass tuning parameter (RP q) were carried out, using digested blood diluted 1 + 9 with deionized water and spiked with 1 μg L −1 of Al, Cr, Mn, V and 5 μg L −1 of As and Se. Detection limits were determined in digested blood using the 3 σ criterion. The desolvating system allowed a sufficient sensitivity to be achieved to determine elements at levels of ng L −1 without detriment of signal stability. The accuracy of the method was tested with the whole blood certified reference material (CRM), certified for Al, As, Cd, Co, Cr, Mn, Mo, Ni, Pb, Sb, Se, and V, and with indicative values for Ba, Li, Sn, Sr, and Zr. The addition calibration approach was chosen for analysis. In order to confirm the DRC data, samples were also analyzed by means of sector field inductively coupled plasma mass spectrometry (SF-ICP-MS), operating in medium ( m/Δ m = 4000) and high ( m/Δ m = 10,000) resolution mode and achieving a good agreement between the two techniques.

A method for precise analysis of trace element/calcium ratios in carbonate samples using quadrupole inductively coupled plasma mass spectrometry

An improved method has been developed using a quadrupole inductively coupled plasma mass spectrometer (Q‐ICP‐MS) to analyze carbonate samples for multiple trace element to calcium ratios. Problems alleviating shorter‐term drift have been overcome by manipulating the instrument to bracket each trace metal measurement with a calcium measurement, while longer‐term drift is corrected by bracketing each sample analysis with external matrix‐matched standards, of typical foram composition. Our method is optimized for measuring the ratios, Sr/Ca, Mg/Ca, Zn/Ca, Cd/Ca, Ba/Ca, Mn/Ca, and U/Ca, from a single carbonate sample but could be adapted to include a range of alternative ratios. Evaluation has shown the method to be extremely precise. At less than 1 RSD (1σ) for 3 trace metal to calcium ratios, we have achieved comparable precision to a sector field ICP‐MS instrument and an advance over previous methods using the Q‐ICP‐MS instrument. Precision (RSD) for each ratio, based on 96 sample analyses in 5 batches made over a period of 9 months using a 100 mg/L Ca standard, is 2.2% for U/Ca, 1.7% for Cd/Ca, 1.9% for Zn/Ca, 1.1% for Ba/Ca, 0.7% for Mn/Ca, and 0.7% and 0.6% for Sr/Ca and Mg/Ca, respectively. Accuracy of the method is confirmed by comparing standard ratios with those obtained from an ICP‐AES instrument and by comparing sample analyses of NEAP4B material from the North Atlantic with data measured using thermal ionization mass spectrometry (TIMS) and flame atomic absorption spectroscopy (FAAS).

Bandpass reaction cell inductively coupled plasma mass spectrometry for the determination of silver and cadmium in samples in the presence of excess Zr, Nb and Mo

An inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) equipped with a Dynamic Reaction Cell™ (DRC) was used to reduce the oxide interferences for the accurate determination of Ag and Cd in samples in the presence of excess Zr, Nb and Mo. The effect of the operating conditions of the DRC system was studied to obtain the best signal to noise ratios for 109 Ag and 111 Cd . The potentially interfering polyatomic ions 93 Nb 16 O +, 92 Zr 16 OH +, 92 Mo 16 OH +, 95 Mo 16 O +, 94 Zr 16 OH + and 94 Mo 16 OH + on 109 Ag + and 111 Cd + determination were decreased in intensity to an insignificant level by using O 2 as the reaction gas. Furthermore, a rejection parameter q (Rpq) of 0.6 was used to filter out unwanted precursors of interfering species from the ion beam to eliminate interferences created in the reaction cell. The detection limit was ca. 2 and 3 pg ml −1 for 109 Ag and 111 Cd , respectively, with the DRC ICP-MS method. The method was applied to the determination of Ag and Cd in NIST SRM 2709 San Joaquin soil reference material as well as NIST SRM 1568a rice flour reference material. The precision between sample replicates was better than 5.7% and the analysis results were in good agreement with the expected values.

Determination of selenium in biological materials by isotope dilution analysis with an octapole reaction system ICP-MS

An inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) with an octapole reaction system (ORS) was used for the determination of selenium by isotope dilution analysis (IDA) in biological reference materials and serum samples from healthy subjects. The potentially interfering argon dimers (40Ar38Ar+ and 40Ar2+) at the selenium masses 78 and 80 were almost eliminated by the use of hydrogen as reaction gas. Thus, the detection limits were improved five times for 78Se and the measurement of 80Se (the main selenium isotope with an abundance of 49.61%) is now possible. An enriched 77Se solution was prepared and characterized by reverse IDA and isotope ratios measured were 78Se/77Se and 80Se/77Se. Instrumental parameters were optimised in order to obtain optimal precision and accuracy in the isotope ratio measurement of Se by ORS-ICP-QMS. The precision achieved for the isotope ratio measurements reached 0.2% (RSD for n = 5) for both ratios. Systematic errors, including detector dead time (47 ± 2 ns), mass bias effects (about 3%) and spectroscopic interferences due to the presence of bromine in the samples, were corrected. The accuracy of the measured selenium isotope ratios was improved by correcting the intensity signals of the selenium isotopes for SeH+ formation (about 3%). The proposed IDA method has been applied to the determination of Se in biological reference materials (serum, urine and tissues) and the results showed good agreement with the certified values.

Dynamic reaction cell inductively coupled plasma mass spectrometry for determination of silicon in steel

An inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) equipped with a dynamic reaction cell™ (DRC) was used for the determination of silicon in steel samples. The effect of the operating conditions of the DRC system was studied to get the best signal-to-noise ratio for 28Si. The intensity of potentially interfering ions 12C 16O + and 14N 14N + at the silicon mass m/ z 28 were reduced significantly by using NH 3 as the reaction cell gas in the DRC. The signal-to-background ratio was improved more than one order by using the DRC system. Validation of the method was carried out by the determination of silicon in steel standard reference materials (NIST SRM 15h and SRM 368). Good agreement was obtained between the certified values and the experimental results. The accuracy was better than 3% for all the determinations. The detection limit for silicon was in the range of 0.2 ng ml −1 which corresponds to 2 μg g −1 in the original sample. The precision (R.S.D.) between sample replicates was better than 5% for all the determinations.

Determination of vanadium in water samples by reaction cell inductively coupled plasma quadrupole mass spectrometry

An inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) equipped with a dynamic reaction cell (DRC) was used for the determination of vanadium and its species in water samples. The effect of the operating conditions of the DRC system was studied in order to obtain the best signal to noise ratios. The potentially interfering 35Cl16O+ and 34S16OH+ at the vanadium m/z value of 51 were reduced in intensity by approximately four orders of magnitude by using NH3 as the reaction cell gas in the DRC. The detection limit for 51V was 0.006 ng ml−1. In addition, reversed-phase ion-pair liquid chromatography (LC) was coupled with ICP-MS for the determination of various vanadium species. The limits of detection for VIV and VV were 0.007 and 0.013 ng ml−1 V at m/z 51, respectively, based on peak height. This method was applied to the determination of vanadium in NRCC SLRS-3 Riverine Water reference sample, NRCC SLEW-2 Estuarine Water reference sample and water samples collected locally. The result for the reference sample SLRS-3 agreed satisfactorily with the reference value. The results for which no reference values were available were also found to have satisfactory recoveries. The recovery was in the range of 87–109% and the precision between sample replicates was better than 14% for all the determinations.

Validation of methylmercury determinations in aquatic systems by alkyl derivatization methods for GC analysis using ICP-IDMS.

Isotope dilution mass spectrometry (IDMS), using an inductively coupled plasma quadrupole mass spectrometer (ICPMS) and a species-specific methylmercury spike was applied to validate the commonly used GC method for methylmercury (MeHg+) determination, which is based on the formation of volatile methylethylmercury by derivatizationwith NaBEt4. The spike compound, Me201Hg+, was synthesized by reaction of 201Hg-enriched mercury chloride with methylcobalamin. By analyzing different environmental aquatic samples, it was found that in most cases, transformation of MeHg+ into elemental mercury (Hg0) took place. From investigations of synthetic solutions, it could be followed that halide ions are responsible for this transformation process. Chloride and bromide converted MeHg+ into Hg0, whereas iodide caused transformation into Hg2+ and Hg0. It could also be shown that transformation of MeHg+ took place only during the derivatization step. In contrast to ethylation, propylation by NaBPr4 did not cause any transformation; however, accurate results of MeHg+ determinations could be obtained by propylation as well as by ethylation when GC/ ICP-IDMS was applied. This work demonstrates the great power of isotopically labeled element compounds for the validation of element speciation methods and for species-specific IDMS analyses.