Mechanism of generation of volatile hydrides of trace elements by aqueous tetrahydroborate(III). Mass spectrometric studies on reaction products and intermediates

The mechanism of generation of volatile metal/metalloid hydrides by derivatization with borane complexes is presented. This reaction has been employed for ultratrace element analysis since 1972 and has been the source of much controversy in regard to the reaction mechanism. Here we investigated this derivatization by using As(III), Sb(III), Bi(III), MeAsO(OH)2, and Me2AsO(OH) as model analytes and NaBH4, NaBD4, tert-BuNH2BH3, and Me2NHBH3 as borane reagents. The identification of reaction products and intermediates observed under various reaction conditions was performed by gas chromatography/mass spectrometry and electrospray ionization mass spectrometry. An alternative reaction model, based on the formation of analyte-borane complex (ABC) intermediates, is able to reconcile all the experimental evidence reported in the literature. In this study, we provide definitive evidence of the ABC hydride generation mechanism, which shows that the generation of volatile hydrides occurs via formation of ABC intermediates between hydroboron species and the analyte substrate followed by the direct transfer of hydrogen from boron to the analyte atom, and fast hydrolysis leading to the final product.     

Quantum dot-based headspace single-drop microextraction technique for optical sensing of volatile species

Core-shell CdSe/ZnS quantum dots (QDs) dispersed in a droplet of organic solvent have been applied for the first time as luminescent probes for the selective detection of volatile species. Luminescence quenching caused by volatile species was examined after their trapping onto a drop using the headspace single-drop microextraction (HS-SDME) approach along with microvolume fluorospectrometry. The novel method is characterized by low reagent and sample consumption, especially regarding QDs, a reduction about 500-fold for each analysis being attained in comparison with luminescent probing in aqueous phase using conventional luminescence spectrometers with 1 cm quartz cells for measurement. To assess QDs as luminescent probes along with HS-SDME, 14 volatile species were tried. Strong luminescence quenching (i.e., I(0)/I > 2.5) was observed for species such as CH(3)Hg(+) and Se(IV) after hydridation with NaBH(4). Moderate luminescent quenching (I(0)/I ≈ 2) was observed for species such as Hg(II) after its conversion into Hg(0), H(2)S, and methylcyclopentadienyl-manganese tricarbonyl (MMT). Small luminescence quenching effects (i.e., 1< I(0)/I <2) were caused by other hydride forming species such as As(III), Sb(III), Te(IV), and Bi(III), as well as SnBu(4), volatile amines, and endosulfan. Detection limits of 6.3 × 10(-9) and 1.6 × 10(-7) M were obtained for Se(IV) and CH(3)Hg(+), respectively. Repeatability expressed as relative standard deviation (N = 7) was about 5%. QD-HS-SDME-μvolume-fluorospectrometry allows one to carry out matrix separation, preconcentration, and confinement of QDs, hence achieving a selective, sensitive, fast, environmentally friendly, and miniaturized luminescence assay.     

Synthesis and purification of some main group organometallic precursors for compound semiconductors

Metal-organic vapour phase epitaxy/chemical vapour deposition (MOVPE/MOCVD) has emerged recently as the method of choice for large scale preparation of a variety of low dimension inorganic materials; particularly compound semiconductors, used in modern electronic and opto-electronic devices. The success of this process depends on the availability of suitable molecular precursors of desired purity. Group V hydrides (e.g. NH₃, PH₃, AsH₃, SbH₃) have been employed conventionally for deposition of III-V semiconductor materials. Inherent weakness of this hydride source, particularly heavier ones (for instance very low utilization (> 0.1%) of AsH₃ in GaAs synthesis; ∼ 4 h half life of SbH₃ at room temperature) has been a driving force to develop new molecular precursors with desirable properties. This talk will briefly review synthesis and purification of several precursors of groups III (Ga, In), IV, V (As, Sb) and VI (Se, Te).     

Volatile analytes formed from arsenosugars: determination by HPLC-HG-ICPMS and implications for arsenic speciation analyses

It is generally accepted that the use of the hydride generation method to produce volatile analytes from arsenic compounds is restricted to the two inorganic forms (As(III) and As(V)) and the three simple methylated species methylarsonate (MA), dimethylarsinate (DMA), and trimethylarsine oxide. We report here that arsenosugars, major arsenic compounds in marine organisms, produce volatile analytes by the hydride generation (HG) method without a prior mineralization/oxidation step and that they can be quantitatively determined using HPLC-HG-ICPMS. The hydride generation efficiency depends on the type of hydride generation system and is influenced by the concentration of HCl and NaBH(4). For the four arsenosugars investigated, the hydride generation efficiencies were approximately 21-28% (or 4-6%, depending on the HG system) that obtained for As(III) under conditions optimized for As(III). This hydride efficiency was less than that shown by MA ( approximately 68% relative to As(III)) and DMA ( approximately 75%) but greater than that displayed by As(V) ( approximately 18%). Analysis of two species of brown algae, Fucus serratus and Hizikia fusiforme, by HPLC-HG-ICPMS produced results comparable with those obtained from other techniques used in our laboratory (HPLC-ICPMS and LC-ESMS for F. serratus) and with results from other laboratories taking part in a round robin exercise (H. fusiforme). This study shows for the first time the quantitative determination of arsenosugars using the hydride generation method without a decomposition step and has considerable implications for analytical methods for determining inorganic arsenic based on the formation of volatile hydrides.     

Transition Probabilities of Forbidden Lines

This paper describes calculations of the transition probabilities of forbidden lines (magnetic dipole and electric quadrupole radiation) of laboratory and astrophysical interest. Results are given for Ti III, Cr II, Cr IV, Mn V, Mn VI, Fe VI, Fe VII, Ni I, Cu II, Ga I, Ge I, Ge II, As I, As III, Se I, Br I, Br II, Kr II, Kr III, Rb III, In I, Sn I, Sn II, Sb I, Sb III, Te I, I I, I II, Xe II, Xe III, Cs III, Hg II, Tl I, Pb I, Pb II, Bi I, Bi II, Bi III, Po I, and Rn II.     

Sampling of trace volatile metal(loid) compounds in ambient air using polymer bags: a convenient method

The sampling of volatile metal(loid) compounds (VOMs) such as hydrides, methylated, and permethylated species of arsenic, antimony, and tin is described using Tedlar bags. Advantages as well as limitations and constraints are discussed and compared to other widely used sampling techniques within this area, namely, stainless steel canisters, cryotrapping, and solid adsorbent cartridges. To prove the suitability of Tedlar bags for the sampling of volatile metal(loid) compounds, series of stability tests have been run using both laboratory synthetic and real samples analyzed periodically after increasing periods of storage. The samples have been stored in the dark at 20 degrees C and at 50 degrees C. Various volatile arsenic species (AsH3, MeAsH2, Me2AsH, Me3As), tin species (SnH4, MeSnH3, Me2SnH2, Me3SnH, Me4Sn, BuSnH3), and antimony species (SbH3, MeSbH2, Me2SbH, Me3Sb) have been generated using hydride generation methodology and mixed with moisturized air. Three static gaseous atmospheres with concentrations of 0.3-18 ng/L for the various compounds have been generated in Tedlar bags, and the stability of the VOMs has been monitored over a period of 5 weeks. Sewage sludge digester gas samples have been stored only at 20 degrees C for a period of 48 h. Cryotrapping GC/ICPMS has been used for the determination of the VOMs with a relative standard deviation of 5% for 100 pg. After 8 h, the recovery rate of all the compounds in the air atmospheres was better than 95% at 20 and 50 degrees C, whereas the recovery after 24 h was found to be between 81 and 99% for all VOMs at 20 and 50 degrees C except for Me3Sb and Me3As. These species show a loss between 48 and 73% at both temperatures. After 5 weeks at 20 degrees C, a loss of only 25-50% for arsine and stibine and the above-mentioned tin compounds was determined. Only Me3Sb, Me3Bi, and Me2Te were present in the digester gas sample. After 24 h, losses of 44, 10, and 12%, respectively, could be determined. Given these results, Tedlar bags could even be used, with some limitations, for long-term sampling of air containing traces of VOMs. The loss is more pronounced at higher temperatures.     

Role of hydroboron intermediates in the mechanism of chemical vapor generation in strongly acidic media

Unknown and controversial aspects related to the mechanisms of hydrolysis of borane complexes and to the mechanisms of chemical vapor generation for trace element determination in strongly acidic media (0.01-10 M HCl) have been investigated and clarified. The overall hydrolysis rates of borane complexes (BH(4)(-), H(3)N-BH(3)) in the acidity range of 0.2-10 M HCl were several orders of magnitude lower than those predicted by kinetics laws and obtained in the pH range of 3.8-14. The decomposition of the borane complexes takes place stepwise and proceeds through the formation of hydroboron intermediates, L(x)()BH(4)(-)(x)()(n)() (x = 1, 2, 3), where L could be one or more species among the donor groups H(2)O, NH(3), OH(-), and Cl(-) and n is the charge of the hydroboron species (n = 0, +1, -1, depending on L). Some intermediates present surprisingly long lifetimes at elevated acidities and play a key role in determining both the overall hydrolysis rates of borane complexes and the reactivity of Hg(II), As(III), Sb(III), Bi(III), Se(IV), Te(IV), and Sn(IV) in chemical vapor generation for trace element determination. Atomic absorption experiments demonstrated that almost all trihydroboron species (LBH(3)(n)()), dihydroboron species (L(2)BH(2)(n)()), and monohydroboron species (L(3)BH(n)()) play an active role in the generation of elemental mercury and stibine. Some of these intermediates are inactive or play a marginal role in the generation of arsine, bismuthine, and hydrogen selenide. Hydrogen telluride is preferentially formed by those hydroboron species, which are stable in strongly acidic conditions, while the same species are unreactive in the generation of stannane. The collected experimental evidence is in agreement with the general reactivity of the elements in chemical vapor generation techniques and, together with other literature data, definitely rule out the hypothesis of "nascent hydrogen" as a possible mechanism of chemical vapor generation by borane complex derivatization.     

Vapor generation by UV irradiation for sample introduction with atomic spectrometry

Volatile species of the conventional hydride-forming elements (As, Bi, Sb, Se, Sn, Pb, Cd, Te), Hg, transition metals (Ni, Co, Cu, Fe), noble metals (Ag, Au, Rh, Pd, Pt), and nonmetals (I, S) were generated following UV irradiation of their aqueous solutions to which low molecular weight carboxylic acids (formic, acetic, propionic) had been added. Free radicals arising from photodissociation of the latter provide a new and useful alternative to the common methods of chemical/electrochemical vapor generation techniques for the determination of these analytes by atomic spectrometry. Quantitative estimates of the efficiencies of these generation processes were not undertaken, although calculated signal-to-background ratios (>1500 for 5 ng/mL As, Sb, Bi, Se, and Te; 20 for 10 ng/mL Sn, Cu, Rh, Au, Pd, Pt, and Cd; 2400 for 1 ng/mL Hg; and 1000 for Co using ICP-TOF-MS detection) do provide clear evidence of the efficacy of this approach for sample introduction. In the case of Ni and Se, the tetracarbonyl and alkylated selenium compounds have been identified, respectively.     

Determination of lead in wine and rum samples by flow injection-hydride generation-atomic absorption spectrometry

A method for direct determination of lead in wine and rum samples was developed, using a flow injection hydride generation system coupled to an atomic absorption spectrometer with flame-quartz atomizer (FI-HG-AAS). Lead hyride (PbH(4)) was generated using potassium ferricyanide (K(3)Fe(CN)(6)), as oxidant and sodium tetrahydroborate (NaBH(4)) as reductant. Samples were acidified to 0.40% (v/v) HCl for wine and to 0.30% (v/v) HCl for rum, which were then mixed on-line with 3% (m/v) K(3)Fe(CN)(6) solution in 0.03% (v/v) HCl prior to reaction with 0.2% (m/v) alkaline NaBH(4) solution. Lead contents of a rum and two different red wine samples were determined by FI-HG-AAS agreed with those obtained by ICP-MS. The analytical figures of merit of method developed were determined. The calibration curve was linear up to 8.0 microg L(-1) Pb with a regression coefficient of 0.998. The relative error was lower than 4.58%. The relative standard deviation (n=7) was better than 12%. A detection limit of 0.16 microg L(-1) was achieved for a sample volume of 170 microL.     

相变光盘记录介质Sb-Se系和Ge-Sb-Te系合金组织及结构

按照配方熔炼制成Sb-Se系和Ge-Sb-Te系合金,对其组织结构进行了观察测试,研究结果表明,制备的合金组织比较均匀,X射线衍射结果表明,Sb-Se系合金1＃样品有Sb析出,2＃样品有Se析出,符合化学计量比的3＃样品全部形成Sb2Se3共晶体。Ge-Sb-Te系合金5＃样品有Sb析出,而符合化学计量比的4＃样品形成GeSb2Te4共晶体。     

On-line preconcentration and determination of mercury in biological and environmental samples by cold vapor-atomic absorption spectrometry

An on-line procedure for the determination of traces of total mercury in environmental and biological samples is described. The present methodology combines cold vapor generation associated to atomic absorption spectrometry (CV-AAS) with preconcentration of the analyte on a minicolumn packed with activated carbon. The retained analyte was quantitatively eluted from the minicolumn with nitric acid. After that, volatile specie of mercury was generated by merging the acidified sample and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the atomizer device. Optimizations of both, preconcentration and mercury volatile specie generation variables were carried out using two level full factorial design (2(3)) with 3 replicates of the central point. Considering a sample consumption of 25mL, an enrichment factor of 13-fold was obtained. The detection limit (3sigma) was 10ngL(-1) and the precision (relative standard deviation) was 3.1% (n=10) at the 5microgL(-1) level. The calibration curve using the preconcentration system for mercury was linear with a correlation coefficient of 0.9995 at levels near the detection limit up to at least 1000microgL(-1). Satisfactory results were obtained for the analysis of mercury in tap water and hair samples.     

Comparison of pneumatic nebulization and hydride generation inductively coupled plasma mass spectrometry for isotopic analysis of selenium

A comparative investigation between pneumatic nebulization and continuous hydride generation as sample introduction methods for inductively coupled plasma mass spectrometry was carried out for isotopic analysis of selenium in biological samples of interest to human metabolic studies. Experimental parameters known to affect the analytical performance of the system were evaluated: instrument operating parameters, analyte solution/NaBH4 flow rate, and NaBH4 concentration. Signal-to-background ratio was examined for the three stable isotopes 74Se, 77Se, and 82Se. While background count rates for the hydride system were 3-5 times larger than those for the nebulization method, the signal-to-background ratios, normalized for Se concentration, were 30-50 times greater for the hydride system. Absolute detection limits (3 sigma) for the two systems were 20-60 (nebulization) and 0.6-1.8 (hydride) ng of Se. Overall memory of the hydride system was evaluated. Measurable effects were observed within 400 s from switching to analyte solution with differing isotopic composition, only if the sequence of analysis was from high to low ratio (1-4% bias). However, if the sequence was from low to high ratio, precise and linear calibration plots could be obtained over the isotope ratio range of an order of magnitude or higher. While further improvements might lead to potential enhancement of sensitivity and precision of as much as an order of magnitude, the present performance of the hydride system was satisfactory in relation to the requirements of isotopic analysis for metabolic investigations employing 74Se as the in vivo stable isotope tracer.     

A Study of Some Thermophysical Parameters in Glassy \mathrm{{Se}}_{80}\mathrm{{Te}}_{20} and \mathrm{{Se}}_{80}\mathrm{{Te}}_{10}\mathrm{{M}}_{10} (Cd, In, and Sb) Alloys

The present paper reports a comparative study of some thermophysical properties (thermal conductivity, thermal diffusivity, thermal effusivity, and specific heat per unit volume) for $\mathrm{{Se}}_{80}\mathrm{{Te}}_{20}$ Se 80 Te 20 and $\mathrm{{Se}}_{80}\mathrm{{Te}}_{10}\mathrm{{M}}_{10}$ Se 80 Te 10 M 10 (Cd, In, and Sb) alloys. The transient plane source technique is used for this purpose. The thermal conductivity is highest for $\mathrm{{Se}}_{80}\mathrm{{Te}}_{10}\mathrm{{In}}_{10}$ Se 80 Te 10 In 10 as compared to the other ternary alloys. This is explained in terms of the thermal conductivity of additive elements Cd, In, and Sb. The composition dependence of the thermal diffusivity and specific heat per unit volume is also discussed.     

Simultaneous Determination of Volatile Metal (Pb, Hg, Sn, In, Ga) and Nonmetal Species (Se, P, As) in Different Atmospheres by Cryofocusing and Detection by ICPMS

A sensitive method for multielemental speciation analysis of volatile metal and metalloid compounds in air has been developed. The analytes are sampled simultaneously in the field by cryofocusing on a small glass wool-packed column at -175 °C. Detection is performed in the laboratory by low-temperature GC hyphenated with ICPMS. Oxygen addition in the carrier gas was used to reduce interferences originating from the presence of volatile carbon-containing species in the samples. Plasma stability during analysis was monitored continuously by internal standardization (Xe). This system provides routine absolute detection limits of 0.06-0.07 pg (as Pb) for tetraalkyllead species (Me(4)Pb, Et(4)Pb), 0.2 pg (as Sn) for tetraalkyltin species (Me(4)Sn, Et(4)Sn), 0.8 pg (as Hg) for mercury species (Hg(0), Me(2)Hg, Et(2)Hg), and 2.5 pg (as Se) for selenium species (Me(2)Se). This instrumentation makes it possible to collect small air sample volumes and has been successfully applied to the determination of volatile metal and metalloid species in the atmosphere in urban and rural locations. Qualitative application in the semiconductor industry is also reported with regard to the detection of arsenic (ASH(3), tert-butylarsine), phosphorus (PH(3), tert-butylphosphine), alkylindium, and gallium species.     

Determination of arsenobetaine, arsenocholine, and tetramethylarsonium cations by liquid chromatography-thermochemical hydride generation-atomic absorption spectrometry

A novel high-performance liquid chromatography-atomic absorption spectrometry (HPLC-AAS) interface based on thermochemical hydride generation has been developed and optimized for the determination of arsenobetaine [(CH3)3As+CH2COOH], arsenocholine [(CH3)3As+CH2CH2OH], and tetramethylarsonium [(CH3)4As+] cations. In this quartz interface, the methanolic HPLC eluent was nebulized by thermospray effect and pyrolyzed in a methanol/oxygen kinetic flame and the analytes were thermochemically derivatized to the hydride derivative in the presence of excess hydrogen. The volatile derivative was then transported to a cool diffusion H2/O2 flame atomizer. The fact that arsenic pentoxide was also derivatized, and that no signal was observed in the absence of postthermospray hydrogen or the absence of cool diffusion flame, corroborated the thermochemically mediated arsine-generation mechanism. Factorial models predicting the performance of the interface at different levels of five selected variables suggested that (a) both reverse- and normal-phase HPLC eluents were compatible with the interface and (b) the performance of this system was relatively insensitive (less than 50% variation in response) to changes over wide ranges in the operating parameters. At concentrations up to 10-fold excess, potential interferents [(CH3)3S+, (CH3)3Pb+] did not affect, significantly, the postulated thermochemical hydride generation (THG) process. However, a 10-fold molar excess of (CH3)3Se+ decreased the response of the analyte by 48%. Virtually identical responses were observed for equimolar amounts of tetramethylarsonium, arsenocholine, arsenobetaine [As(-III)], and dimethylarsinic acid [As(III)]. Arsenic pentoxide [As(V)] was detected with 75% efficiency, relative to the response of the organoarsenic compounds.(ABSTRACT TRUNCATED AT 250 WORDS)     

Structure and ionization potentials of clusters containing heavy elements

Several structures of homonuclear clusters of heavy group V and group VI elements (As, Sb, Se, Te) have been investigated. In addition, mixed clusters of these atoms and alkali elements (Li through Cs) have been considered. In all cases, bond lengths, atomization energies and vertical ionization potentials have been determined in valence-only ab-initio calculations using energy-adjusted pseudopotentials. Comparison with experimental values is made where possible.     

Identification of volatile selenium compounds produced in the hydride generation system from organoselenium compounds

We report a novel aqueous derivatization of selenomethionine (Semet), selenoethionine (Seet) and trimethylselenonium ion (TmSe) by NaBH4 and HCI to volatile selenium species, namely, diethyldiselenide (DeDSe), dimethyldiselenide (DMDSe), dimethylselenide (DmSe) and ethylhydrogenselenide (ESeH), in the hydride generation (HG) system. The volatile selenium compounds produced in the HG system were on-line trapped and concentrated in a U-tube that was immersed in the liquid nitrogen trap. The trapped volatile Se compounds were volatilized at 80 degrees C in a water bath, and 50-500 microL of volatile gas was injected into the GC/AED and GC/MS, respectively. It has been established that DmSe, DmDSe, and DeDSe are the predominant Se compounds that are produced in the HG system from TmSe, Semet, and Seet, respectively, followed by ESeH from Seet. Analytical methods previously employed have stated that these compounds are inactive in the HG system. Prior decomposition of Semet, Seet, and TmSe to selenous acid is essential before HG. To the best of our knowledge, current findings for the production and identification of volatile selenium compounds in the HG system are new and different from existing reports; hence, direct estimation of Semet, Seet, and TmSe is possible when coupling with a HG system using a suitable Se-specific detector.     

氢化物发生ICP-AES法同时测定废水中的铅镉铜锌镍铬汞

废水样品经消解后与氯化亚锡经自制简易氢化物装置混合产生氢化物,与样液一起导入等离子体中,氢化物发生测定汞并同时测定铅、镉、铜、锌、镍、铬等元素。氢化物发生大大提高了汞的检测灵敏度,仪器检出限为0.001mg.L-1,其他六种元素的检出限为0.002～0.012mg.L-1;相对标准偏差为0.60%～1.00%,回收率为97%～102%。     

MOCVD of Bi2Te3 and Sb2Te3 on GaAs substrates for thin-film thermoelectric applications

Metal organic chemical vapour deposition (MOCVD) has been investigated for growth of Bi2Te3 and Sb2Te3 films on (001) GaAs substrates using trimethylbismuth, triethylantimony and diisopropyltelluride as metal organic sources. The surface morphologies of Bi2Te3 and Sb2Te3 films were strongly dependent on the deposition temperatures as it varies from a step-flow growth mode to island coalescence structures depending on deposition temperature. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor ratio of VI/V and deposition temperature. By optimizing growth parameters, we could clearly observe an electrically intrinsic region of the carrier concentration over the 240 K in Bi2Te3 films. The high Seebeck coefficient (of -160 microVK(-1) for Bi2Te3 and +110 microVK(-1) for Sb2Te3 films, respectively) and good surface morphologies of these materials are promising for the fabrication of a few nm thick periodic Bi2Te3/Sb2Te3 super lattice structures for thin film thermoelectric device applications.     

Atomization of hydride with a low-temperature, atmospheric pressure dielectric barrier discharge and its application to arsenic speciation with atomic absorption spectrometry

This paper describes a novel hydride atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma. The plasma was generated with a 3700-V, 20.3-kHz, and 5-W electrical power supply and easily sustained with inert gases (He or Ar) at a flow rate of 250 mL.min(-1) after optimization. However, it cannot be sustained with N2. This atomizer offers the advantages of low operation temperature and low power consumption in comparison with the currently used electrothermal quartz atomization operated at 900 degrees C with a power supply of several hundred watts. To confirm the utility of the proposed atomizer, four arsenic species (As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA)) were determined by the present atomization technique. A hyphenation of HPLC coupled to hydride generation AAS with the optimized DBD atomizer has been successfully used for the speciation of arsenic in order to demonstrate the potential of this atomizer in the present study. The characteristics of the DBD atomizer and the effects of different parameters (discharge gas, gas flow rate, voltage, HCl concentration, KBH4 concentration) are discussed in the paper. Compared with other hydride atomization techniques, the proposed method shows the following features: (1) small size (70 mm x 15 mm x 5 mm), which is preferable for the miniaturization of the total analytical system; (2) low power consumption (< or =5 W), which indicates the possibility of the development of portable, fieldable analytical instrumentation for in situ detection using battery as power supply; (3) low atomizer temperature (approximately 70 degrees C), which is in favor of the compactness of the total instruments; (4) avoidance of residue moisture removal in comparison with the existed GD system, which leads to the facility of the system. The analytical figures of the present technique were evaluated. The detection limits of As(III), As(V), MMA, and DMA obtained with HG-DBD-AAS were 1.0, 11.8, 2.0, and 18.0 microg.L(-1), respectively. The accuracy of the system was verified by the determination of arsenic in reference material of orchard leaves SRM 1571. The concentration of As determined by the present method agreed well with the reference values. The speciation of arsenic in the freeze-dried urine SRM 2670 were carried out, and the results obtained were in agreement with the results of HPLC-ICPMS and the reported values by other laboratories.