Graphite Tube Research Articles

Determination of fluorine in tea using high-resolution molecular absorption spectrometry with electrothermal vaporization of the calcium mono-fluoride CaF

High-resolution continuum source molecular absorption of the calcium mono-fluoride molecule CaF in a graphite furnace has been used to determine fluorine in tea after acid digestion, alkaline solubilization and preparation of a conventional aqueous infusion. The strongest absorption ‘line’ of the CaF molecule is at 606.440nm, which is part of the rotational fine structure of the X2Σ+−A2Π electronic transition; it has a bond dissociation energy of 529kJmol−1, which is comparable with other molecules used for fluorine determination. One advantage of using Ca as the molecule-forming reagent is that spectral interferences are extremely unlikely in the spectral range of its strongest absorption. Another advantage is that Ca acts both as molecule forming reagent and chemical modifier, so that no other reagent has to be added, making the method very simple. The only disadvantage is that Ca has a somewhat negative influence on the graphite tube lifetime. The limit of detection was found to be 0.16mgL−1 F, corresponding to 1.6ng F absolute, and the calibration curve was linear in the range between 0.5 and 25mgL−1 with a correlation coefficient of R=0.9994. The results obtained for a certified tea reference material were in agreement with the certified value on a 95% confidence level. There was also no difference between the results obtained after an acid digestion and an alkaline solubilization for 10 tea samples, based on a paired t-test. The values found in the 10 samples ranged between 42μgg−1 and 87μgg−1 F; the tea infusions contained between 21μgg−1 and 56μgg−1 F, with an extraction rate between 48% and 74%.

A Polypyrrole-Based Sorptive Microextraction Coating for Preconcentration of Malathion from Aquatic Media

A new micro-solid phase extraction method was developed by combining solid-phase extraction and stir bar sorptive extraction to benefit from the advantages of both techniques. A polypyrrole coating was electrochemically synthesized on the surface of an already used graphite furnace, employed in electro-thermal atomic absorption spectroscopy. The cylindrical geometry of the graphite tube provided a rather huge surface area, suitable for sorptive extraction. The novel sorbent coating was examined as an extracting medium to isolate malathion. Effects of different parameters such as extraction time, salt concentration, sample volume, desorption solvent and time were investigated and optimized. Under the optimized conditions, the limit of detection and limit of quantification of the developed method were 5 and 20 ng L−1, respectively. The calibration curve showed linearity in the range of 0.1–100 μg L−1 (R 2 = 0.9968). The precision was evaluated at 0.1 and 1 μg L−1 concentration levels and relative standard deviations (n = 3) were found to be 10 and 7%, respectively. The developed method was successfully applied to the extraction of malathion from real river water and tap water samples, and relative recoveries at the spiked level of 0.1 μg L−1 were 94 and 97%, respectively.

Electrochemical hydride generation of tin(II) and its determination by electrothermal atomic absorption spectrometry with in situ trapping in the graphite tube atomizer

An electrolytic hydride generation system for the determination of tin(II) by means of batch electrochemical hydride generation-electrothermal atomic absorption spectrometry (EcHG-ETAAS) with in situ trapping in a graphite tube atomizer is described. The effects of four permanent chemical modifiers – palladium, tungsten, iridium, and platinum – for graphite tube treatment on analyte absorbance and the effects of four cathode materials, i.e., Pb, Sn, Pb–Sn alloy, and glassy carbon, are checked. Three electrolytes, i.e., nitric acid, sulfuric acid, and hydrochloric acid, are examined as catholyte solutions. The influence of several parameters on EcHG is investigated using multivariate and univariate methods. Interferences of some concomitant ions are evaluated. The calibration curve is linear from 1 to 200 µg L−1, with a detection limit of 0.8 µg L−1 and a relative standard deviation of 6.2% (n = 3) for 100 µg L−1 Sn(II). The proposed method was successfully applied in the analysis of real environmental water samples and reference materials, and good spiked recoveries over the range of 93.1–115% were obtained. The proposed technique provides a means for developing hydride generation of other elements.

Method development and optimization for the determination of selenium in bean and soil samples using hydride generation electrothermal atomic absorption spectrometry

The present investigation is the first part of an initiative to prepare a regional map of the natural abundance of selenium in various areas of Brazil, based on the analysis of bean and soil samples. Continuous-flow hydride generation electrothermal atomic absorption spectrometry (HG-ET AAS) with in situ trapping on an iridium-coated graphite tube has been chosen because of the high sensitivity and relative simplicity. The microwave-assisted acid digestion for bean and soil samples was tested for complete recovery of inorganic and organic selenium compounds (selenomethionine). The reduction of Se(VI) to Se(IV) was optimized in order to guarantee that there is no back-oxidation, which is of importance when digested samples are not analyzed immediately after the reduction step. The limits of detection and quantification of the method were 30ngL−1 Se and 101ngL−1 Se, respectively, corresponding to about 3ngg−1 and 10ngg−1, respectively, in the solid samples, considering a typical dilution factor of 100 for the digestion process. The results obtained for two certified food reference materials (CRM), soybean and rice, and for a soil and sediment CRM confirmed the validity of the investigated method. The selenium content found in a number of selected bean samples varied between 5.5±0.4ngg−1 and 1726±55ngg−1, and that in soil samples varied between 113±6.5ngg−1 and 1692±21ngg−1.

Speciation of Mercury in Environmental Water Samples with Seasonal Change

Mercury concentrations and speciation were determined in surface water samples taken from rivers in the vicinity of industrial area, in Johore Malaysia. Samples were collected from the same sites before and immediately after rainfall. The aim of this study is to assess the influence of seasonal change in river water on the concentration of mercury (Hg) species. Trace concentrations of mercury in water samples were determined by a method involving a simple and rapid procedure involving the flow-injection inductively coupled plasma mass spectrometry (FI-ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS) techniques. Mercury vapor, generated by sodium borohydride as the reductant, was stabilized by potassium dichromate (K2Cr2O7), then released by controlled heating and detected by FI-ICP-MS. Methyl mercury (II) was preconcentrated using the ammonium pyrolidindithiocarbamate (APDTC)-chloroform extraction procedure and the chloroform extract was introduced into the graphite tube. The absolute detection limits were found to be 0.204 μg L-1 and 0.273 μg L-1 for total mercury and methyl mercury respectively, with thevariability being lower than 5% relative standard deviation (RSD) at the 5 μg L-1 level. Because of the high stability of MeHg (II)-APDTC complexes, it is possible to evaporate the extract in order to obtain a crystalline powder to be dissolved with a few micro liters of chloroform enacting MeHg (II) and Hg (II) can be detected at sub-nanogram levels.

Fast heating induced impulse halogenation of refractory sample components in electrothermal atomic absorption spectrometry by direct injection of a liquid halogenating agent

A novel electrothermal atomic absorption spectrometry (ETAAS) method was developed for the halogenation of refractory sample components (Er, Nd and Nb) of lithium niobate (LiNbO3) and bismuth tellurite (Bi2TeO5) optical single crystals to overcome memory effects and carry-over. For this purpose, the cleaning step of a regular graphite furnace heating program was replaced with a halogenation cycle. In this cycle, after the graphite tube cooled to room temperature, a 20μL aliquot of liquid carbon tetrachloride (CCl4) was dispensed with a conventional autosampler into the graphite tube. The CCl4 was partially dried at 80°C under the mini-flow (40cm3min−1) condition of the Ar internal furnace gas (IFG), then the residue was decomposed (pyrolyzed) by fast furnace heating at 1900–2100°C under interrupted flow of the IFG. This step was followed by a clean-out stage at 2100°C under the maximum flow of the IFG. The advantage of the present method is that it does not require any alteration to the graphite furnace gas supply system in contrast to most of the formerly introduced halogenation techniques.The effectiveness of the halogenation method was verified with the determination of Er and Nd dopants in the optical crystals. In these analyses, a sensitivity decrease was observed, which was likely due to the enhanced deterioration of the graphite tube surface. Therefore, the application of mathematical correction (resloping) of the calibration was also required. The calibration curves were linear up to 1.5 and 10μmolL−1 for Er and Nd, respectively. Characteristic masses of 18 and 241pg and the limit of detection (LOD) values of 0.017 and 0.27μmolL−1 were found for Er and Nd, respectively. These LOD data correspond to 0.68μmolmol−1 Er and 11μmolmol−1 Nd in solid bismuth tellurite samples. The analytical results were compared with those obtained by a conventional ETAAS method and validated with X-ray fluorescence spectrometry analysis.

Design considerations regarding an atomizer for multi-element electrothermal atomic absorption spectrometry

The methodology of simultaneous multi-element electrothermal atomic absorption spectrometry (ETAAS-Electrothermal Atomic Absorption Spectrometry) stipulates rigid requirements to the design and operation of the atomizer. It must provide high degree of atomization for the group of analytes, invariant respective to the vaporization kinetics and heating ramp residence time of atoms in the absorption volume and absence of memory effects from major sample components. For the low resolution spectrometer with a continuum radiation source the reduced compared to traditional ETAAS (Electrothermal Atomic Absorption Spectrometry) sensitivity should be, at least partially, compensated by creating high density of atomic vapor in the absorption pulse. The sought-for characteristics were obtained for the 18 mm in length and 2.5 mm in internal diameter longitudinally heated graphite tube atomizer furnished with 2–4.5 mg of ring shaped carbon fiber yarn collector. The collector located next to the sampling port provides large substrate area that helps to keep the sample and its residue in the central part of the tube after drying. The collector also provides a “platform” effect that delays the vaporization and stipulates vapor release into absorption volume having already stabilized gas temperature. Due to the shape of external surface of the tube, presence of collector and rapid (about 10 °C/ms) heating, an inverse temperature distribution along the tube is attained at the beginnings of the atomization and cleaning steps. The effect is employed for cleaning of the atomizer using the set of short maximum power heating pulses. Preparation, optimal maintenance of the atomizer and its compliance to the multi-element determination requirements are evaluated and discussed. The experimental setup provides direct simultaneous determination of large group of element within 3–4 order concentration range. Limits of detection are close to those for sequential single element determination in Flame AAS with primary line source that is 50–1000 times higher than the limits obtainable with common ETAAS (Electrothermal Atomic Absorption Spectrometry) instrumentation.

Direct determination of P in biodiesel by high-resolution continuum source graphite furnace atomic absorption spectrometry

The direct determination of P in biodiesel by high-resolution continuum source graphite furnace atomic absorption spectrometry has been investigated. A slow drying stage proved to be essential for good repeatability. Optimization was performed by a D optimal planning. The atomization temperature and modifier composition were the most relevant parameters. Thus, using a mixture of Pd (30 μg) and Mg(NO 3) 2 (20 μg) as the modifier, previously deposited onto the platform of the graphite tube and dried, a five step drying stage, and pyrolysis and atomization temperatures of 1000 and 2700 °C, respectively, a limit of detection of 0.5 μg g − 1 was obtained. The analysis of biodiesel of different origins confirmed that external calibration with organic P standard solutions, diluted in P-free biodiesel, could be used. In this way, excellent agreement between the found and expected results was observed in the analysis of an ANP interlaboratorial exercise sample.

Determination of trace lithium in human erythrocytes by electrothermal atomic-absorption spectrometry with pyrocoated graphite tubes and integrated platform.

Electrothermal graphite-furnace atomic-absorption spectroscopy with pyrocoated graphite tubes, integrated platform and matrix modification was used to determine submicromolar concentrations of trace lithium in human red blood cells. Matrix-matched samples were used to establish calibration curves for concentrations up to 0.58 microM (addition-calibration method) with satisfactory linearity (r2 > 0.99) and intra- and inter-day variability (CV < 11.4%). The median concentration of trace lithium in the cells of 40 healthy Caucasian volunteers devoid of medical or psychiatric history was 0.23 microM (inter-quartile range 0.20-0.30). The levels of trace lithium in the red blood cells correlated (r2 = 0.83) with plasma concentrations (median 0.13 microM, inter-quartile range 0.11-0.19) measured in the same blood sample. Dietary factors (e.g. consumption of lithium-containing mineral water) affected both levels. The red blood cell/plasma lithium ratio had a median value of 1.57 (inter-quartile range 1.16-2.07), implying that trace lithium is accumulated in erythrocytes. This contrasts with most reports of red blood cell/plasma ratio, measured during therapeutic treatment with lithium, for which the average value is 0.5-0.8, albeit for much higher concentrations of lithium (approx. 500-800 microM). The proposed analytical method has the required sensitivity and accuracy for determination of trace lithium in red blood cells and makes it possible to perform epidemiological studies to assess human exposure to environmental lithium in diet and beverages, and inter-individual variations in trans-membrane and renal lithium kinetics at the submicromolar level.

A simple and fast procedure for the determination of Al, Cu, Fe and Mn in biodiesel using high-resolution continuum source electrothermal atomic absorption spectrometry

A procedure for the determination of Al, Cu, Fe and Mn in biodiesel samples by high resolution continuum source electrothermal atomic absorption spectrometry is proposed. Sample preparation consists in simply diluting the biodiesel samples with ethanol at room temperature. For Al determination, a Zr-treated graphite tube was used as permanent modifier; for the other analytes no modifier was required. Calibration was carried out against aqueous standards, except for Al, for which calibration solutions were prepared using ethanol. Accuracy was verified by means of recovery tests and comparison with the results obtained using a different analytical procedure. The precision, expressed as the relative standard deviation, was typically better than 7%. Detection limits at ng g −1 levels for all analytes were obtained. The concentration of the analytes in biodiesel samples was generally very low, around a few tens of ng g −1, except for two samples for which the Fe concentrations were in the μg g −1 level. The proposed method has proved to be simple, precise and accurate.

Characterisation of carbon blacks produced by solar thermal dissociation of methane

Solar methane dissociation appears as a possible route toward a hydrogen-based economy. The competitiveness of the process strongly depends on the carbon black properties and economic value. At CNRS-PROMES, a 50 kW tubular solar reactor was developed to produce carbon black and hydrogen from methane. The reaction was carried out in a graphite receiver crossed by seven graphite tubes heated up by concentrated solar radiations at the 1 MW CNRS solar furnace. The temperatures ranged between 1608 K and 1928 K and the methane flow-rates varied from 10.5 to 21 NL/min. Total methane dissociation was reached with hydrogen yield higher than 80% and the carbon yield was drastically affected by the acetylene by-product. The carbon samples were analysed in detail and their properties were compared to a commercial conductive grade carbon black. Transmission electron microscopy showed primary particles of 10–70 nm diameter. The crystallinity of the samples was characterised by Raman spectroscopy. It was also possible to correlate the specific surface area with the reaction temperature and with the concentrations of residual methane and of the acetylene by-product. The resistivity and the structure of the agglomerates were determined by simultaneous measurements of the conductivity and the density under compression.

Simultaneous determination of Cr, Fe, Ni and V in crude oil by emulsion sampling graphite furnace atomic absorption spectrometry

In this work a simple and reliable method for the simultaneous determination of Cr, Fe, Ni and V in crude oil, using emulsion sampling graphite furnace atomic absorption spectrometry is proposed. Under the best conditions, sample masses around 50 mg were weighed in polypropylene tubes and emulsified in a mixture of 0.5% (v v−1) hexane + 6% (m v−1) Triton X-100®. Considering the compromised conditions, the pyrolysis an atomization temperatures for the simultaneous determination of Cr, Fe, Ni and V were 1400 °C and 2500 °C, respectively. Aliquots of 20 μL of reference solution and sample emulsion were co-injected into the graphite tube with 10 μL of 1.0 g L−1Mg(NO3)2 as chemical modifier. The detection limits (n = 10, 3σ) and characteristic masses were, respectively: 0.07 μg g−1 and 19 pg for Cr; 2.15 μg g−1 and 31 pg for Fe; 1.25 μg g−1 and 44 pg for Ni; and 1.15 μg g−1 and 149 pg for V. The reliability of the proposed method was checked by fuel oil Standard Reference Material (SRMTriton X-100®1634c – NIST) analysis. The concentrations found presented no statistical differences compared to the certified values at 95% confidence level.

Characterization of condensed phase beryllium species in the presence of aluminium and silicon matrices during electrothermal heating on graphite and tungsten platforms

Condensed phase beryllium species occurring on graphite and tungsten platforms in the presence of aluminium and silicon matrices were characterised over a wide temperature range. The solid residue was viewed by scanning electron microscopy (SEM), while the chemical composition was probed by energy dispersive (ED) X-ray spectrometry (XRS), Fourier transform-infrared (FT-IR) spectrometry and Raman microanalysis. Beryllium oxide phases were found to be the predominant species over a wide temperature range, persisting up to about 1800 °C on the graphite platform. Beryllium metal species were also identified at high temperatures (1500 °C), but the transformation of beryllium oxide to beryllium was influenced by the amount and localised behaviour of concomitant species on the platform surface. For graphite platform atomisation, aluminium and silicon concomitants are present as metal oxides. Other silicon species, such as silicon carbide, were found mainly at temperatures above 900 °C. Little or no beryllium oxide was found on tungsten platforms up to 1800 °C, although there was evidence of some beryllium alloyed to tungsten. Tungsten from the platform supports some hydration forming different tungsten oxidation states (W6+, W5+, W4+). Also, at 900 °C, silicon was present as an oxide, but also as elemental silicon, silicon carbide, and silicon alloyed to tungsten forming tungsten disilicide at the surface interface. When tungsten platform atomisation was used for samples containing silicon, evidence of degradation of the graphite tube through formation of carbon clusters and nanostructures was more easily noticeable and evaluated by Raman spectrometry.

Determination of Trace Amounts of Lead by Modified Graphite Furnace Atomic Absorption Spectrometry after Liquid Phase Microextraction with Pyrimidine-2-thiol

The liquid phase microextraction (LPME) was combined with the modified Graphite furnace atomic absorption spectrometry (GF-AAS) for determination of lead in the water and solid samples. In a preconcentration step, lead was extracted from a 2 ml of its aqueous sample in the pH = 5 as lead-Pyrimidine-2-thiol cationic complex into a 4 µl drop of 1,2 dichloroethane and ammonium tetraphenylborate as counter ion immersed in the solution. In the drop, the lead-Pyrimidine-2-thiol ammonium tetraphenylborate ion associated complex was formed. After extraction, the microdrop was retracted and directly transferred into a graphite tube modified by [W.Pd.Mg] (c). Some effective parameters on extraction and complex formation, such as type and volume of organic solvent, pH, concentration of chelating agent and counter ion, extraction time, stirring rate and effect of salt were optimized. Under the optimum conditions, the enrichment factor and recovery were 525% and 94%, respectively. The calibration graph was linear in the range of 0.01 - 12 µg?L–1 with correlation coefficient of 0.9975 under the optimum conditions of the recommended procedure. The detection limit based on the 3Sb criterion was 0.0072 µg?L–1 and relative standard deviation (RSD) for ten replicate measurement of 0.1 µg?L–1 and 0.4 µg?L–1 lead was 4.5% and 3.8% respectively. The characteristic concentration was 0.0065 µg?L–1 equivalent to a characteristic mass of 26 fg. The results for determination of lead in reference materials, spiked tap water and seawater demonstrated the accuracy, recovery and applicability of the presented method.

A fast and accurate method for the determination of total and soluble fluorine in toothpaste using high-resolution graphite furnace molecular absorption spectrometry and its comparison with established techniques

A fast and reliable method has been developed for the determination of total and soluble fluorine in toothpaste, important quality control parameters in dentifrices. The method is based on the molecular absorption of gallium mono-fluoride, GaF, using a commercially available high-resolution continuum source atomic absorption spectrometer. Transversely heated platform tubes with zirconium as permanent chemical modifier were used throughout. Before each sample injection, a palladium and zirconium modifier solution and a gallium reagent were deposited onto the graphite platform and thermally pretreated to transform them into their active forms. The samples were only diluted and introduced directly into the graphite tube together with additional gallium reagent. Under these conditions the fluoride was stable up to a pyrolysis temperature of 550 °C, and the optimum vaporization (molecule formation) temperature was 1550 °C. The GaF molecular absorption was measured at 211.248 nm, and the limits of detection and quantification were 5.2 pg and 17 pg, respectively, corresponding to a limit of quantification of about 30 μg g −1 (ppm) F in the original toothpaste. The proposed method was used for the determination of total and soluble fluorine content in toothpaste samples from different manufactures. The samples contained different ionic fluoride species and sodium monofluorophosphate (MFP) with covalently bonded fluorine. The results for total fluorine were compared with those obtained with a modified conventional headspace gas chromatographic procedure. Accuracy and precision of the two procedures were comparable, but the proposed procedure was much less labor-intensive, and about five times faster than the latter one.

The use of gold nanoparticles as an effective modifier for the determination of arsenic and antimony by electrothermal atomic absorption spectrometry

Gold nanoparticles (AuNPs) were used as a new chemical modifier for the determination of arsenic and antimony in salt solutions by electrothermal atomic absorption spectrometry. The AuNPs were prepared by reducing chloroauric acid with sodium citrate. The effects of pyrolysis and atomization temperatures, the amounts of interferents and modifier on the sensitivities of arsenic and antimony were investigated. As and Sb remain in the graphite tube up to 1,100°C, which is sufficient for the determination of the two metals in certified reference materials and spiked sea water samples within a 95% confidence level with low RSD (<10%). The detection limits (N = 10 at 3σ) for As and Sb in sea water are 2.3 μg L-1 and 3.0 μg L-1, respectively. Almost no background as well as a blank value was detected for AuNPs.

Experimental constraints on the role of chloride in the origin and evolution of kimberlitic magma

graphite tube isolated from a capsule with the sample by the MgO insulator was applied as a heater. The sample powder was loaded in a Au-Pd or Pt capsule and after accurate drying welded by arc welding. The inner walls of Ptcapsules were shielded by Re foil for minimization of iron loss. Each cell contained two capsules: one with the composition of model kimberlite (this study) and another with the composition of natural kimberlite. The results of experiments with the natural composi� tion will be presented in the next paper. The tempera� ture in each run was controlled by a W97Re3-W75Re25 thermocouple located in the center of the heater and isolated by the Al2O3 insulator from it. The tempera� ture gradient in the sample measured using a two� pyroxene thermometer did not exceed 50°С at 1500°С and 5 GPa. The pressure in the sample was maintained by the calibration performed at room tem� perature by change in the electric resistance for the transitions Bi I-II (2.55 GPa), Ba I-II (5.5 GPa), and Bi III-IV (7.7 GPa) and corrected for high tempera� tures by phase transitions graphite-diamond, quartz- coesite, and garnet-perovskite in the CaGeO 3 system. The error in pressure measurement was estimated on the level of 0.2 GPa. The composition of phases was determined on a JEOL Superprobe JXA�8800 micro� probe analyzer at Tohoku University.

Lanthanum coated graphite tube - graphite furnace atomic absorption spectrometry for determination of trace barium in urine

目的 建立测定尿液中微量钡的涂镧石墨管-石墨炉原子吸收光谱法。方法采用1％的硝酸酸化尿样，用硝酸铵和硝酸镁做基体改进剂消除干扰，涂镧石墨管-石墨炉原子吸收光谱法测定尿样中的微量钡。结果钡在0～300t．μg／L浓度范围线性关系良好，相关系数为0．9996，直线回归方程y=0．00187x=0．00130。检出限为3．15μg/L，最低检出浓度6．3μg／L。低中高浓度钡溶液日内精密度分别为3．7％、2．9％、2．2％，日间精密度分别为5．1％、3．2％、2．8％，回收率为88．0％～91．0％。结论该方法灵敏度和准确度较高，能够满足尿液中微量钡的测定。

Particle Loss in a Scanning Mobility Particle Analyzer Sampling Extension Tube

Deposition of particles in sampling lines may occur due to various physical forces. Particles in the nanoscale are not highly susceptible to inertial or sedimentary deposition, and electrical losses are reportedly controlled by using conductive tubing. Particle losses from diffusion affect size distribution and number concentration. Selectively removing the smallest particles has the effect of increasing the statistical measure of particle size-the geometric mean-while decreasing number concentration and geometric standard deviation. Quantification of losses is necessary to interpret or correct the data. Sample loss from a rigid graphitic or flexible Tygon tube attached to a scanning mobility particle sizer inlet was investigated during sampling at the Center for Nanophase Materials Sciences. Mean concentrations and particle size parameters determined from samples collected with and without sample inlet extensions were compared. Number concentration decreased and mean particle size increased for both tubing types at lengths of approximately 0.7 m.

The use of 1-phenyl-3-methyl-4-benzoyl-5-pyrazone as chemical modifier for low-temperature electrothermal vaporization for separation and determination of Cr(III) and Cr(VI) by ICP-MS

Based on thermal stability and volatility of 1-phenyl-3-methyl-4-benzoyl-5-pyrazone (PMBP) chelate, a novel method was described for the determination of Cr(III) and Cr(VI) by low-temperature electrothermal vaporization (LETV) combined with inductively coupled plasma mass spectrometry (ICP-MS). It was found that Cr(III) could be rapidly formed in a graphite furnace, and quantitatively vaporized into ICP at a relatively low temperature of 1000 °C with the use of PMBP as a chemical modifier, while Cr(VI) was retained in the graphite tube. Thus, the separation of Cr(III) and Cr(VI) could be realized. The main factors affecting the formation and vaporization of Cr(III)-PMBP chelate were investigated in detail. Under the optimized conditions, the detection limit of Cr(III) for this method was 0.031 ng mL −1 and the relative standard deviation (RSD) for 1.0 ng mL −1 Cr(III) was 5.3% ( n = 9, v = 10 μL). The linear range of calibration curve spanned three orders of magnitude. The proposed method was applied to the determination of Cr(III) and Cr(VI) in water samples with satisfactory results.