Conventional Hydride Generation Research Articles

Photochemical Hydride Generation in Sulfite Medium: Sample Introduction into an Inductively Coupled Plasma Mass Spectrometer for the Determination of Ultratrace Inorganic Arsenic.

This Technical Note reports a new UV photochemical hydride generation (PHG) of As(III/V) in a sulfite medium. Combining PHG for sample introduction with sector field inductively coupled plasma mass spectrometry (SF-ICPMS) for detection, we established a novel and ultrasensitive approach for the determination of total inorganic As. Arsine was generated simply by exposing arsenic solutions containing 2 mM of sodium sulfite to UV irradiation for 10 s with 1 mM of sodium formate for sensitivity enhancement. An impressive limit of detection of 0.2 ng/L for As, suitable for the quantitation of inorganic arsenic at ultratrace levels, was readily achieved. Formation of hydrated electrons and hydrogen radicals was experimentally validated, and this may be responsible for the reduction of the high-valent arsenic species. The PHG may also provide a new and useful alternative to conventional hydride generation and photochemical vapor generation for the determination of other trace elements, such as Se(VI) and Te(VI), and by other atomic spectrometric techniques.

Electrothermal Desolvation-Enhanced Dielectric Barrier Discharge Plasma-Induced Vapor Generation for Sensitive Determination of Antimony by Atomic Fluorescence Spectrometry.

A novel simple electrothermal desolvation-enhanced dielectric barrier discharge plasma-induced vapor generation (ETD-DBD-PIVG) method has been developed for sensitive Sb determination by atomic fluorescence spectrometry (AFS). In our proposed ETD-DBD-PIVG, 20 μL sample solution was dried first; then, the resulting solution residue was directly converted into molecular volatile species efficiently through the interactions with hydrogen-doped DBD plasma; and finally, it was transported to AFS for detection. It was found that the desolvation process could greatly enhance Sb vapor generation, and the Sb fluorescence signal intensity is almost independent of its speciation, where comparable sensitivity is achieved for Sb(III) and Sb(V), enabling efficient total Sb detection without pre-reduction. Influencing parameters were evaluated in detail, including heating time, discharge gap, solution pH, and flow rates of argon and hydrogen, as well as coexisting ion interference. Under optimized conditions, the limit of detection was calculated as 0.86 μg L-1 (17.2 pg) for Sb. The accuracy of the proposed method was validated by the analysis of certified reference materials of simulated natural water samples and several river water samples. Compared with conventional hydride generation, the new ETD-DBD-PIVG offers an alternative green vapor generation technique with several advantages: (1) it eliminates the use of a sample flow system (e.g., no use of any syringe or peristaltic pump); instead, 20 μL of a sample is directly pipetted onto the glass plate for analysis; (2) it greatly simplifies the sample pretreatment steps as no pre-reduction process is needed; (3) it is sensitive and suitable for volume-limited sample analysis: efficient Sb vapor generation without chemical reducing reagents in ETD-DBD-PIVG enables Sb detection with an absolute limit at the picogram level. All the results demonstrate that the proposed method provides a simple, green, and sensitive method for Sb determination and it can also be extended to other elements such as Cd and As.

In situ formation of silver nanoparticles via hydride generation: A miniaturized/portable visual colorimetric system for arsenic detection in environmental water samples

A miniaturized/portable visual colorimetric system based on hydride generation headspace solid phase extraction (HG-HS-SPE) was proposed for arsenic detection by naked eyes. As(III) was transformed into AsH3via hydride generation process, the volatile AsH3 was introduced into reaction bottle and reacted with AgNO3 subsequently. Silver nanoparticles (Ag NPs) were generated in situ, resulting in the color changed from white to black, it could be readout by naked eyes or a smartphone application (color extraction, for RGB readout). The interferences from 9 common ions and 10 conventional hydride generation elements were discussed, the results demonstrated that the proposed method exhibit a good anti-interference. The proposed visual colorimetric method was further applied to seven water samples and their spiked samples, and a certified reference water sample (GBW08605) for demonstrating its accuracy and applicability.

Direct and Sensitive Determination of Antimony in Water by Hydrogen-Doped Solution Anode Glow Discharge-Optical Emission Spectrometry Without Hydride Generation.

In the present work, a novel, simple, and sensitive method for the direct determination of trace Sb in water samples was developed based on hydrogen-doped solution anode glow discharge-optical emission spectrometry (SAGD-OES). It was found that the vapor generation and excitation of Sb occurred simultaneously in the SAGD, contributing to the significant improvement in the sensitivity of Sb as compared with normal pure He-operated SAGD or solution cathode glow discharge. Besides, the proposed hydrogen-doped SAGD-OES could be operated even at pH = 14, which could reduce the interference of coexisting ions as many metal ions could be precipitated and removed. Our results demonstrated that the proposed method offered good tolerance to the interferences of Li, Na, Ca, Mg, Fe, Ni, Mn, and Zn ions even at a concentration of 50 mg L-1. Under optimized conditions, the limit of detection of Sb was 0.85 μg L-1, which was comparable to that of microplasma sources coupled with conventional hydride generation. The linearity of the Sb calibration curve reached R2 > 0.999 in the 5-5000 μg L-1 range. Finally, the accuracy of the proposed method was validated by the determination of certified reference materials [GSB 07-1376-2001 (1) and (2))] and real water samples. The proposed low-power (6 W), green, sensitive, rapid, and robust method provides a promising approach for on-site trace Sb analysis and may also be extended to other elements.

Investigation of the conditions for selenium determination by photochemical vapor generation coupled to graphite furnace atomic absorption spectrometry

In this study instrumental parameters and sample preparation methods for Se determination using photochemical vapor generation (PVG) coupled to graphite furnace atomic absorption spectrometry (GF AAS) were investigated. Coconut water was selected as sample due to its nutritional importance and matrix complexity. The PVG was performed in a flow injection mode. The Se volatile species, generated in the UV reactor, were separated from the condensed phase in a gas-liquid separator and introduced automatically in the graphite furnace. These species were trapped on the integrated graphite platform surface coated with Ir as permanent modifier. The PVG conditions such as concentration of low molecular weight organic compound (LMWC), sample and carrier gas flow rate, effect of reagents frequently used in sample preparation (HNO3 and H2O2) were investigated. Formic acid 0.44 mol L−1 was selected as LMWC. The addition of HNO3 (14 mmol L−1) and H2O2 (145 mmol L−1) increased the sensitivity. Pre-reduction of Se (VI) to Se (IV) was performed on-line in a quartz spiral tube coated with a thin film of TiO2. The insertion of Ar flow rate (115 mL min−1) before the reactor inlet has improved the sensitivity, comparing with the introduction of Ar after the reactor. UV-assisted photo-oxidation of coconut water samples was employed as an alternative sample preparation to avoid the NO3−/NO2−, and H2O2 interference. The figures of merit were: sensitivity 0.0680 s ng−1, limits of detection and quantification 0.65 μg L−1 and 2.2 μg L−1, respectively, and characteristic mass of 62 pg. The PVG efficiency was estimated as 79% when comparing with conventional hydride generation. Furthermore, a mass balance study was accomplished in order to identify possible analyte losses in the PVG system, which the overall recovery was up to 85%. The results of recovery tests accomplished with real samples of coconut waters varied between 80 and 103% for Se (IV), Se (VI), and selenomethionine.

Enhanced Photochemical Vapor Generation for the Determination of Bismuth by Inductively Coupled Plasma Mass Spectrometry.

An enhanced photochemical vapor generation (PVG) sample introduction procedure is developed for the determination of trace Bi with inductively coupled plasma mass spectrometry (ICP MS) by the addition of iron. Gas chromatography mass spectrometry (GC-MS) reveals that (CH3)3Bi is the major component of the volatile Bi species formed in the presence of 20% (v/v) acetic acid, 5% (v/v) formic acid, and 60 μg mL-1 Fe3+ under UV irradiation. The addition of Fe3+ not only largely increases the PVG efficiency of Bi3+ but also accelerates the reaction kinetics of photochemical reduction of Bi3+. The analytical sensitivity was enhanced 30-fold using PVG for sample introduction compared to that for direct solution nebulization detection by ICP MS detection. Furthermore, the proposed method shows much better tolerance of interference from Cu2+ and Ni2+ than that from conventional hydride generation (HG). Under the optimized conditions, a detection limit of 0.3 ng L-1 was obtained for Bi by ICP MS determination. The relative standard deviation (RSD) was 2.5% for seven replicate measurements of 0.5 ng mL-1 Bi3+ standard solution. The proposed method has been successfully applied for the determination of Bi in environmental samples, including water samples, and certified reference material of soil (GSS-1) and sediments (GSD-5a and GSD-10) with satisfying results.

Non-aqueous phase cold vapor generation and determination of trace cadmium by atomic fluorescence spectrometry

Cold vapor generation (CVG) of cadmium was firstly accomplished in non-aqueous media by using solid reductant of potassium borohydride (KBH4) as a derivation reagent. The mixture of surfactant Triton X-114 micelle and octanol was innovatively used as the non-aqueous media for the CVG and atomic fluorescence spectrometry (AFS) was used for the elemental determination. The analyte ions were firstly extracted into the non-aqueous media from the bulk aqueous phase of analyte/sample solution via a novelly established ultrasound-assisted rapidly synergistic cloud point extraction (UARS-CPE) process and then directly mixed with the solid redcutant KBH4 to generate volatile elemental state cadmium in a specially designed reactor, which was then rapidly transported to a commercial atomic fluorescence spectrometer for detection. Under the optimal conditions, the limit of detection (LOD) for cadmium was 0.004 μg L−1. Compared to conventional hydride generation (HG)-AFS, the efficiency of non-aqueous phase CVG and the analytical performance of the developed system was considerably improved.

Determination of trace cadmium in rice by liquid spray dielectric barrier discharge induced plasma − chemical vapor generation coupled with atomic fluorescence spectrometry

Cadmium contamination in rice has become an increasing concern in many countries including China. A simple, cost-effective, and highly sensitive method was developed for the determination of trace cadmium in rice samples based on a new high-efficient liquid spray dielectric barrier discharge induced plasma (LSDBD) vapor generation coupled with atomic fluorescence spectrometry (AFS). The analytical procedure involves the efficient formation of Cd volatile species by LSDBD plasma induced chemical processes without the use of any reducing reagents (Na/KBH4 in conventional hydride generation). The effects of the addition of organic substances, different discharge parameters such as discharge voltage and discharge gap, as well as the foreign ion interferences were investigated. Under optimized conditions, a detection limit of 0.01μgL−1 and a precision of 0.8% (RSD, n=5, 1μgL−1 Cd) was readily achieved. The calibration curve was linear in the range between 0.1 and 10μgL−1, with a correlation coefficient of R2=0.9995. Compared with the conventional acid-BH4− vapor generation, the proposed method not only eliminates the use of unstable and expensive reagents, but also offers high tolerance for coexisting ions, which is well suited to the direct analysis of environmental samples. The validation of the proposed method was demonstrated by the analysis of Cd in reference material of rice (GBW080684). It was also successfully applied to the determination of trace cadmium in locally collected 11 rice samples, and the obtained Cd concentrations are ranged from 7.2 to 517.7μgkg−1.

Ultrasonic Nebulization/UV Photolysis Vapor Generation Sample Introduction System for the Determination of Conventional Hydride (As, Bi, Sb, Se, Sn) and Cold Vapor (Hg, Cd) Generation Elements in Reference Materials in the Presence of Acetic Acid by Microwave-Induced Plasma Spectrometry

ABSTRACT A novel synergic effect of ultrasonic nebulization (USN) and ultraviolet (UV) radiation (photolysis) when used in combination has been exploited for efficient generation of conventional hydride elements (As, Bi, Sb, Se, Sn), Hg vapor, and volatile molecular Cd species. Several UV-based systems were studied, the most advantageous design being an ultrasonic nebulizer fitted with a 6 W mercury pen lamp supplying a microliter sample to a quartz oscillator, converting liquid into aerosol at the entrance of the UV spray chamber. Optimal conditions utilized a 40% v/v solution of acetic acid as the generation medium. The volatile species are detected by microwave-induced plasma optical emission spectrometry (MIP-OES). The experimental concentration detection limits for simultaneous determination, calculated as the concentration giving a signal equal to three times the standard deviation of the blank (LOD, 3σblank criterion, peak height), were 11, 22, 16, 19, 20, 11, and 15 µg L−1 for As, Bi, Sb, Se, Sn, Cd, and Hg, respectively. The method offers relatively good precision (RSD ranged from 3% to 5%) for liquid analysis and microsampling capability. The methodology was validated through determination of elements in two Certified Reference Materials (NRCC DOLT-2, NIST 1643e) and by the aqueous standard calibration technique.

A NOVEL METHOD OF THE HYDRIDE SEPARATION FOR THE DETERMINATION OF ARSENIC AND ANTIMONY BY AAS

A novel method is proposed for the hydride separation when determinining of arsenic and antimony by AAS. A chromatomembrane cell was used as preconcentration-, extraction- and separation-manifold instead of the U-tube phase separator, which is normally fitted in continuous flow vapour systems generating conventionaly the hydrides. The absorbances of the hydrides produced were measured by an atomic absorption spectrophotometer at 193.7 nm and 217.6 nm. Under optimized analytical conditions, the calibration plot for arsenic was linear from 50 to 500 ng.mL-1 (r2 = 0.9982). The precision for three subsequent measurements of 500 ng.mL-1 arsenic gave rise to a relative standard deviation of 0.4%. The detection limit was 15 ng.mL-1, which is much lower compared with that of the conventional hydride system (2000 ng.mL-1). A similar result was observed in case of antimony: the detection limit was 8 ng.mL-1 when the proposed method was applied. Consequently, the sensitivity of the novel method surpasses systems with conventional hydride generation, i.e. the precision and the acuracy increase whereas the standard deviation and the detection limit decrease. The proposed method was applied in pharmacheutial analysis and the certified As-content of a commercial product was very sufficiently confirmed. Keywords: Chromatomembrane Cell, Hydride separation, Arsenic detection, Antimony detection, AAS

Atomic absorption spectrometric determination of trace tellurium after hydride trapping on platinum-coated tungsten coil

In this work, a sensitive and simple method for the determination of tellurium was developed by hyphenation of electrically heated quartz tube atomic absorption spectrometry and tellurium hydride trapping on platinum-coated tungsten coil. With a mixture of Ar and H 2, tellurium hydride was transported to tungsten coil for trapping at 390 °C and releasing at 1200 °C. A limit of detection (LOD, 3 σ) of 0.08 ng mL − 1 was obtained with 1 min trapping (1.5 mL sampling volume), and enhancement factor was 28 compared to conventional hydride generation atomic absorption spectrometry. The LOD was better or at least comparable to literature levels involving on-line trapping and some other sophisticated instrumental method such as graphite furnace atomic absorption spectrometry (GF-AAS) and inductively coupled plasma mass spectrometry (ICP-MS), and it can be further lowered down to 0.03 ng mL − 1 by increasing the trapping time to 4 min. The platinum coating was stable for 300 firings without sensitivity loss. Interference and its alleviation were studied in detail. The proposed method was applied to the determination of tellurium in several geological standard reference materials, and the results were found in good agreement with the certified values.

A novel analytical system involving hydride generation and gold-coated W-coil trapping atomic absorption spectrometry for selenium determination at ng l − 1 level

A novel analytical technique was developed where gaseous hydrogen selenide formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated W-coil atom trap for in situ preconcentration. Gold coating on W-coil was prepared by using an organic solution of Au. The atom trap is held at 165 °C during the collection stage and is heated up to 675 °C for revolatilization; analyte species formed are transported to an externally heated quartz T-tube where the atomization takes place and the transient signal is obtained. The carrier gas consisted of 112.5 ml min − 1 Ar with 75 ml min − 1 H 2 during the collection step and 112.5 ml min − 1 Ar with 450 ml min − 1 H 2 in the revolatilization step. The half width of the transient signal obtained is less than 0.5 s. The RSD for the measurements was found to be 3.9% ( n = 11) for 0.10 µg l − 1 Se using peak height measurements. The calibration plot for 27.0 ml of sample collected in 4.0 min using a flow rate of 6.75 ml min − 1 was linear between 0.13 and 2.0 µg l − 1 of Se. The limit of detection (3 s) is 39 ng l − 1 . The enhancement factor for the characteristic concentration ( C o) was found to be 20.1 when compared to conventional hydride generation atomic absorption spectrometry system without trap. In order to check the accuracy of the method, standard reference material, natural water NIST 1640 was employed; the result was found to be in good agreement with the certified value at the 95% confidence level.

Highly sensitive and interference-free determination of bismuth in environmental samples by electrothermal vaporization atomic fluorescence spectrometry after hydride trapping on iridium-coated tungsten coil

Bismuthine was on-line trapped on tungsten coil and subsequently electrothermally vaporized for the determination by atomic fluorescence spectrometry (AFS). Several noble metals, including Pd, Rh, Pt, and Ir, were explored as permanent chemical modifier for tungsten coil on-line trapping. Investigation showed that Ir gave the best performance, in which bismuthine was on-line trapped on Ir-coated tungsten coil at 560 °C, and then released at 1550 °C for subsequent transfer to AFS by a mixture of Ar and H 2. Under optimum instrumental conditions, the trapping efficiency was found to be 73 ± 3%. With 120 s (12 mL sample volume) trapping time, a limit of detection (LOD) of 4 ng L − 1 was obtained, compared to conventional hydride generation AFS (0.09 μg L − 1 ); the LOD can be lowered down to 1 ng L − 1 by increasing the trapping time to 480 s. The LOD was found to be better or at least comparable to literature levels involving on-line trapping and some other sophisticated instrumental methods such as ICP-MS and GF-AAS. A comprehensive interference study involving conventional hydride-forming elements and some transition metals was carried out, and the result showed that the gas phase interference from other hydride-forming elements was largely reduced, thanks to the use of on-line tungsten coil trapping. Finally, the proposed method was applied to the determination of bismuth in several biological and environmental standard reference materials, and a t-test shows that the analytical results by the proposed method have no significant difference from the certified values at the confidence level of 95%.

Characterization of a multimode sample introduction system (MSIS) for multielement analysis of trace elements in high alloy steels and nickel alloys using axially viewed hydride generation ICP-AES

A commercial multimode sample introduction system (MSIS) was characterized for simultaneous multielement hydride and nonhydride-forming elements (As, Bi, Co, Cr, Fe, Mn, Mo, Ni, Sb, Se, Sn, Ti, V, W) in high alloy steels and nickel alloys by axially viewed ICP-AES. Vapor formed by the NaBH4 reaction and aerosol from a specially designed dual conical spray chamber and pneumatic nebulizer were injected simultaneously into a robust plasma. Spectroscopic effects caused by major and minor elements and nonspectroscopic interferences induced by matrix concomitants were evaluated both for conventional nebulization and for hydride generation. The objective of the study was to establish optimized operating conditions whereby both nonhydride and hydride forming elements could be determined simultaneously. It was observed that the sensitivities of the ‘hydride generating’ elements using a MSIS, were similar to those observed using conventional hydride generation. In comparison to conventional pneumatic nebulization, hydride LODs, were enhanced significantly by factors varying from about 2–20. Limits of detection using the MSIS, for nonhydride elements (Co, Cr, Fe, Mn, Mo, Ni, Ti, V, W) were similar to those reported for the conventional sample introduction system. Several fundamental parameters such as Mg II 280.270/Mg I 285.213 nm ratios, excitation temperature (Tex) and the effect of hydrogen were also determined. The effect of hydrogen, formed during hydride generation, on intensities of nonhydride and hydride forming elements and excitation temperature was evaluated. This is important because hydrogen can modify the properties of the ICP. The effect of variable concentrations of tartaric acid, L-cystein, EDTA, and 1,1,3,3-tetramethy-2-thiourea as retarding agents for reducing deleterious effects of Ni was investigated. The accuracy of the procedure was verified by analyzing several certified reference metallurgical samples. An important conclusion of this multielement study is that the application of the MSIS for simultaneous determination of hydride forming and non-hydride forming elements in complex metallurgical samples by ICP-AES is constrained by matrix derived spectral line interferences.

Dual nebulizer sample introduction system for simultaneous determination of volatile elemental hydrides and other elements

A dual sample introduction system was explored for volatile hydride generation in inductively coupled plasma-optical emission spectrometry (ICP-OES) performed in the radially viewed mode. The system consists of two pneumatic nebulizers connected to the conventional spray chamber of the instrument via a simple adaptor. This configuration permits hydride generation but still allows other elements to be determined by pneumatic nebulization. This work was focused on the optimization of the plasma operating conditions for the determination of As, Hg, Sb and Se and other elements. The excitation conditions of the ICP-OES instrument operated with the dual sample introduction system were also explored. Results showed that the analytical performance of the dual system for the determination of As, Hg, Sb and Se was superior to those of conventional nebulization systems. The dual system also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than conventional nebulization systems. An evaluation of the plasma robustness showed that the gases generated in the hydride reactions did not significantly affect the plasma discharge. Similar to conventional hydride generation techniques, the analysis was susceptible to nonspectroscopic interferences produced by transition metals. Finally, the applicability of the dual nebulization system to practical ICP-OES studies was demonstrated by determining the trace elements in an oyster tissue standard reference material.

On-line pre-reduction of Se(VI) by thiourea for selenium speciation by hydride generation

In this study, thiourea (TU) was novelly developed as a reduction reagent for on-line pre-reduction of selenium(VI) before conventional hydride generation (HG) by KBH 4/NaOH–HCl. After TU on-line pre-reduction, the HG efficiency of Se(VI) has been greatly improved and because even higher than that of the same amount of Se(IV) obtained in the conventional HG system. The possible pre-reduction mechanism is discussed. The detection limit (DL) of selenate reaches 10 pg mL − 1 when using on-line TU pre-reduction followed by HG atomic fluorescence detection. When TU pre-reduction followed by HG is used as an interface between ion-pair high performance liquid chromatography and atomic fluorescence spectrometry, selenocystine, selenomethionine, selenite and selenate can be measured simultaneously and quantitatively. The DLs of these are 0.06, 0.08, 0.05 and 0.04 ng mL − 1 , respectively, and the relative standard deviations of 9 duplicate runs for all the 4 species are less than 5%. Furthermore, it was successfully applied to Se speciation analysis of cultured garlic samples, and validated by determination of total selenium and selenium species in certified reference material NIST 1946.

Development of a direct hydride generation nebulizer for the determination of selenium by inductively coupled plasma optical emission spectrometry

A study was conducted to evaluate the performance of a new direct hydride generation nebulizer system for determination of hydride forming elements by inductively coupled plasma optical emission spectroscopy. This system was designed and optimized to obtain the highest sensitivity. Several experimental designs were used for these purposes. To optimize the individual parameters of the system, and to study the interaction between these parameters for both direct hydride generation nebulizers, a central composite orthogonal design with eight factors was set up. Significant behavioral differences were observed in the two direct hydride generation nebulizers studied. Finally, a 70 μm gas orifice nebulizer exhibits a better detection limit than the 120 μm nebulizer. Generally, for determination of selenium, this new direct hydride generation nebulizer system exhibits a linear dynamic range and detection limit (3 σb) of 3 orders of magnitude and 0.2 μg l −1 for selenium, respectively. This new hydride generator is much simpler system that conventional hydride generation systems, which does not need to be changed to work in normal mode with the inductively coupled plasma, since this system may be used for hydride forming elements and those that do not form them. It produces a rapid response with low memory effect. It reduces the interference level of Ni, Co and Cu to 600, 500 and 5 mg l −1, respectively. The accuracy of the system was verified by the determination of selenium in several standard reference materials of ambient, food and clinical sample matrices. No statistically significant differences (95 confidence level) were obtained between our method and the reference values.

Investigation of the direct hydride generation nebulizer for the determination of arsenic, antimony and selenium in inductively coupled plasma optical emission spectrometry.

A direct hydride generation nebulizer (DHGN) was explored for introduction of the sample in inductively coupled plasma-optical emission spectrometry (ICP-OES) using radially viewed mode. This simple hydride generation system was constructed in our laboratory and requires similar plasma operating conditions to conventional nebulizer-spray-chamber arrangements. This work was focused on the optimization of the operating conditions for hydride generation and evaluation of the main analytical figures of merit for the determination of As, Sb and Se. The excitation conditions of the ICP-OES instrument operated with the DHGN were also explored. Results showed that the analytical performance of the new system for the determination of As, Sb and Se was superior to that of conventional nebulization systems. The DHGN also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than conventional nebulization systems. Evaluation of the plasma robustness showed that gases generated in hydride generation do not significantly affects the plasma discharge. Similar to conventional hydride generation techniques, analysis with DHGN was susceptible to non-spectroscopic interferences produced by transition metals. Finally, the utility of the DHGN in practical ICP-OES studies was demonstrated in the determination of trace elements in an oyster tissue standard reference material.

Hydride generation for the direct determination of trace and ultra-trace level of arsenic and antimony in waters using derivative atomic absorption spectrometry.

A new method is developed for the direct determination of trace and ultra-trace level of arsenic and antimony in waters by hydride generation derivative atomic absorption spectrometry (DHGAAS). The signal model and fundamentals of DHGAAS are described. The effects of atomization temperature, argon flow rate, acidity and concentration of KBH(4)and KI were investigated and analytical conditions were optimized. The sensitivities for arsenic and antimony were increased 36.4 and 27.6 times better than those of conventional hydride generation atomic absorption spectrometry (HGAAS). For a 2 mV min(-1) sensitivity range setting, the characteristic concentration was 0.003 microg L(-1) for arsenic and 0.004 microg L(-1)for antimony, and the detection limits (3sigma) were 0.015 micro g L(-1) for arsenic and 0.020 microg L(-1) for antimony. The proposed method was applied to the determination of arsenic and antimony in several water samples with satisfactory results.

Detection of volatile arsenic chloride species during hydride generation: a new prospectus

Volatile inorganic- and organo-arsenic chloride species were detected following hydride generation. Arsenic trichloride can be formed and sampled from the headspace of arsenate or arsenite solutions following simple acidification to 2–8 M HCl. Mono- and dimethylarsenic chloride species are formed during conventional hydride generation using sodium tetrahydroborate in a HCl medium. Increased HCl concentration in the sample solution promotes the formation of volatile chloride species in the hydride mixtures. The generated arsenic chloride species were characterized using electron impact ionization mass spectrometry.