Speciation Analysis Of Inorganic Arsenic Research Articles

Speciation analysis of inorganic arsenic in water samples using thiol-ligand and cotton fibres followed by ICP-OES determination

ABSTRACT This research aimed to develop a method for the speciation analysis of arsenic species, including As(III) and As(V) in environmental samples. Cotton fibres and thiol-ligands, including ammonium pyrrolidine dithiocarbamate (APDC), L-cysteine, and diethyldithiocarbamic acid (DDTC), were used as a simple solid phase extraction (SPE) followed by arsenic determination using inductively coupled plasma optical emission spectrometry (ICP-OES). The separation parameters were thoroughly investigated, including pH, thiol-ligand concentration, cotton fibre amount, type of eluents, and flow rate. It was found that As(III) could be efficiently separated from As(V) by using a column containing 0.5 g cotton fibres and 0.1% APDC under pH 2. As(III) was then eluted using 5 mL of mixed solvents of 4 M HNO3, 4 M HCl, and 0.5 M H2O2 (1:1:1 v/v). The method was then used to perform a speciation analysis of arsenic in model solutions with As(III) and As(V) concentrations ranging from 10–1000 μg/L. The results showed good recoveries of both arsenic species at 80–120% with a satisfactory percentage relative standard deviation (%RSD). The developed method was subsequently applied for arsenic speciation analysis in the environmental samples, including natural and wastewater samples.

A facile and automated microfluidic electrochemical platform for the in-field speciation analysis of inorganic arsenic

An automated microfluidic electrochemical platform was developed for the rapid in-field analysis of arsenic speciation. Herein, we integrated an electrochemical sensing and microfluidic channel for the simultaneous determination of As(III) and total inorganic As (total iAs) within a single device. The platform was fabricated by assembling a gold nanoparticle-modified screen-printed graphene electrode (AuNP/SPGE) on a hydrophilic polyethylene terephthalate (PET) sheet that was specially designed to enclose a microfluidic channel with dual flow channels for separate determination of the two species. While As(III) can be promptly detected with the AuNP/SPGE on one end, thioglycolic acid stored in glass fiber is employed on the other end to reduce As(V) before being electrochemically analyzed on the AuNP/SPGE as total iAs; the difference represents the amount of As(V). With a wireless potentiostat and a smartphone equipped with Bluetooth technology, the overall procedure can be fully automated and accomplished merely within 9 min. The linear ranges for the determination of As(III) and total iAs were found to be 50–1000 and 100–1500 ng/mL with detection limits of 3.7 and 17 ng/mL, respectively. The proposed method was validated and applied for the inorganic As speciation of various food samples with satisfactory results compared to those obtained with the standard HPLC-ICP‒MS protocol. This novel microfluidic electrochemical platform offers numerous advantages, notably for its simplicity, speed, low cost, and portability for on-site analysis, which conclusively makes it a highly promising analytical device for the speciation of inorganic arsenic.

Preparation of novel bifunctionalized magnetic nanoparticles for sequential speciation analysis of inorganic arsenic

An amino- and mercapto-bifunctionalized magnetic nanocomposite (SMNPs-(NH2 + SH)) was synthesized by modification of silica-coated magnetic nanoparticles (SMNPs) via one-pot co-condensation of 3-aminopropyltriethoxysilane (APTES) and 3-mercaptopropyltrimethoxysilane (MPTMS) for the first time. The bifunctional magnetic nanomaterial was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, X-ray photoelectric spectroscopy, elemental analysis, thermogravimetric analysis and vibrating sample magnetometry, etc. The prepared SMNPs-(NH2 + SH) nanocomposite was employed as magnetic solid-phase extraction (MSPE) sorbent for speciation of inorganic arsenic without any pre-oxidation or pre-reduction process. Different optimal conditions for the MSPE including sample solution pH and volume, adsorbent amount, loading time, eluent composition and volume, and elution time were investigated systematically. As(V) and As(III) were adsorbed simultaneously at pH 4.0, and then desorbed sequentially by 3 % (v/v) HNO3 and 3 % (v/v) HNO3 with 4 % (m/v) mercaptosuccinic acid followed by inductively coupled plasma-mass spectrometry (ICP-MS) analysis with the limits of detection of 15.2 and 24.5 ng/L respectively at an enrichment factor of 10 fold. The reliability of the stepwise speciation strategy based on SMNPs-(NH2 + SH) was validated by analyzing inorganic arsenic species in certified reference material of environmental water as well as mixed standard solutions of As(V) and As(III), and the results were in good accordance with the certified or standard values. The applicability of the SMNPs-(NH2 + SH)-MSPE-ICP-MS method for speciation analysis of inorganic arsenic was evaluated in spiked tap, rain, lake and river water samples at the recoveries of 92 %–102 % and 92 %–100 % with the relative standard deviations of 3.6 %–7.4 % and 2.3 %–8.2 % for As(V) and As(III) respectively. In consideration of the merits of single adsorbent, facile preparation, easy operation and no invasion to labile inorganic arsenic, the bifunctional material based MSPE protocol is attractive for speciation analysis of arsenic in real environmental samples.

A combination approach using two functionalized magnetic nanoparticles for speciation analysis of inorganic arsenic

Mercapto- and amino-functionalized magnetic nanoparticles, Fe3O4@SiO2@MPTMS (SMNPs-MPTMS) and Fe3O4@SiO2@APTES (SMNPs-APTES), have been applied as magnetic solid-phase extraction (MSPE) sorbents to directly extract arsenite (As(III)) and arsenate (As(V)) respectively, followed by inductively coupled plasma-mass spectrometry (ICP-MS) detection. Various MSPE parameters were optimized including dose of magnetic adsorbent, pH of sample solution, loading and elution conditions of analytes, adsorption capacity and reusability of SMNPs-MPTMS and SMNPs-APTES for As(III) and As(V) respectively. Under the optimized MSPE conditions, this combined scheme possesses excellent selectivity and strong anti-interference ability without any oxidation or reduction prior to capture of these two species. It is found that with a 25-fold enrichment factor, the limits of detection of As(III) and As(V) were 23.5 and 10.5 ng L−1, respectively. To verify the reliability of the proposed protocol, a certified reference material of environmental water was analyzed, and the results for inorganic arsenic species were in close agreement with the certified values. The applicability of the combination strategy for speciation analysis of inorganic arsenic was evaluated in spiked tap, river, lake and rain water samples. Good recoveries of 89%–96% and 90%–102% were achieved for As(III) and As(V), respectively, with the relative standard deviation ranges of 3.2%–8.0% and 2.5%–7.6%. Through the characterization of functionalized magnetic nanoparticles and the optimization of MSPE experiment, it is confirmed that the existence of mercapto and amino groups on SMNPs-MPTMS and SMNPs-APTES sorbents are responsible for the extraction of As(III) and As(V), respectively, via coordination and electrostatic interactions.

Simultaneous speciation analysis of inorganic arsenic and methylmercury in edible oil by high-performance liquid chromatography–inductively coupled plasma mass spectrometry

A simultaneous speciation method of arsenic and mercury species by inductively coupled plasma mass spectrometry with a reversed-phase C18 ODS column was developed. The separation of inorganic arsenic (iAs) from As species and inorganic mercury (iHg) from methylmercury (MeHg) were achieved by HPLC with a single mobile phase containing ion-pair reagent and l-cysteine. The limits of detection of iAs and MeHg were 0.05 ng g−1 as As and 0.09 ng g−1 as Hg, respectively. The simultaneous extraction, i-As and MeHg from in edible oil were achieved using 2% (w/w) tetramethylammonium hydroxide (TMAH) solution. The proposed method was successfully applied to the food matrix type CRMs. When the simultaneous speciation was applied to several kinds of edible oil, iAs and MeHg were founded in the concentration range of 0.001 mg kg−1 to 0.010 mg kg−1 and 1.21 ng g−1 to 10.18 ng g−1, respectively.

Sequential determination and chemical speciation analysis of inorganic As and Sb in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by HG AAS.

In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m-3, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m-3). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPoutdoor), inhalable particulate matter (PM10), and total suspended indoor particles (TSPindoor), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m-3, respectively. Trivalent Sb (Sb3+) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPoutdoor, PM10, and TSPindoor, respectively. The presence of Sb and its predominant inorganic form (Sb3+) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.

Extraction of arsenic(III) in aqueous two-phase systems: A new methodology for determination and speciation analysis of inorganic arsenic

This work utilizes the liquid–liquid extraction technique of aqueous two-phase systems (ATPS) formed by a polymer and electrolyte to develop a novel methodology for the extraction, determination, and speciation analysis of inorganic arsenic. To optimize the methodology, the following parameters were studied: pH of the system, nature of the ATPS-forming electrolyte and the polymer, tie-line length (TLL) of the system, type and concentration of extractants, and the mass ratio of the top and bottom phases. The highest extraction (%E = 98%) was obtained for an ATPS composed of L64 + Na2SO4 + H2O, at pH = 6.00, TLL = 33.55% w/w using the ammonium pyrrolidine dithiocarbamate (APDC) extractant in a molar ratio (APDC/As(III)) of 960, and with a mass ratio of 1/4. In these same conditions, As(V) was not extracted satisfactorily (%E = 18%) to ATPS top phase, with a separation factor equal to 530 after three extractions, showing the great potential of the system for the speciation analysis of inorganic arsenic. Moreover, the method was validated employing HG-ICP OES with a coefficient of determination of 0.9957 and limits of detection and quantification equal to 0.20 μg kg−1 and 0.66 μg kg−1, respectively, proving that the method is capable of detecting the low concentrations required by legislation. The relative standard deviation (RSD) values varied between 4.88 and 9.45%, and the RSD in inter-day precision was 11.07%, which are in accordance with the limits of the validation guide used by the National Institute of Metrology, Quality and Technology, COD-CGCRE-008. Furthermore, relative error rates ranged from −7.44 to 9.90% and recovery percentages were between 92.6 and 110% for the accuracy studies. This method was also applied in a spiked tap water sample, presenting a recovery value equal to 87.10%.

An online preconcentration system for speciation analysis of arsenic in seawater by hydride generation flame atomic absorption spectrometry

In this paper, an on-line preconcentration system has been proposed for speciation analysis of inorganic arsenic in seawater. It is based on the selective reaction of As(III) with ammonium pyrrolidine dithiocarbamate (APDC) followed by sorption of the formed complex under a minicolumn containing polytetrafluoroethylene (PTFE). Afterward, arsenic sorbed has been eluted using a 2 mol L−1 hydrochloric acid solution. The preconcentration system was optimized employing multivariate techniques. A two-level full factorial design and a Doehlert matrix were performed to determining the critical conditions of the factors: the acidity of the sample, APDC concentration, and sample flow rate. So, the procedure using the optimized conditions allows the determination of As(III) with limits of detection and quantification of 0.02 and 0.07 μg L−1. Total arsenic has been determined after reduction of As(V) using thiourea in acid media and the limits achieved were 0.03 and 0.09 μg L−1, for detection and quantification, respectively. The precision estimated as the relative standard deviation (RSD) was 5.3%, which was calculated using seven replicates of As(III) solution with a concentration of 0.50 μg L−1. The accuracy of the method was confirmed by the analysis of the certified reference material CASS-4 seawater furnished by the National Research Council of Canada-NRCC. The system proposed was employed for speciation analysis of arsenic in five seawater samples collected from Todos os Santos Bay, Salvador, Brazil. The As(III) contents obtained varied from 0.09 to 0.51 and the total arsenic contents varied from 0.20 to 0.66 μg L−1. The results are in agreement with other data reported in the literature.

Speciation analysis of inorganic arsenic by magnetic solid phase extraction on-line with inductively coupled mass spectrometry determination

Arsenic, one of the main environmental pollutants and potent natural poison, is a chemical element that is spread throughout the Earth's crust. It is well known that the toxicity of arsenic is highly dependent on its chemical forms. Generally, the inorganic species are more toxic than its organics forms, and As(III) is 60 times more toxic than As(V). In environmental waters, arsenic exists predominantly in two chemical forms: As(III) and As(V). In view of these facts, fast, sensitive, accurate and simple analytical methods for the speciation of inorganic arsenic in environmental waters are required. In this work, a new magnetic solid phase extraction with a hydride generation system was coupled on line with inductively coupled plasma mass spectrometry (MSPE-HG-ICP-MS). The new system was based on the retention of As(III) and As(V) in two knotted reactors filled with (Fe3O4) magnetic nanoparticles functionalized with [1,5-bis (2-pyridyl) 3-sulfophenylmethylene] thiocarbonohydrazide (PSTH-MNPs). As(III) and total inorganic As were sequentially eluted in different reduction conditions. The concentration of As(V) was obtained by subtracting As(III) from total As. The system runs in a fully automated way and the method has proved to have a wide linear range and to be precise, sensitive and fast. The detection limits found were 2.7 and 3.2 ng/L for As(III) and total As, respectively; with relative standard deviations (RSDs) of 2.5% and 2.7% and a sample throughput of 14.4 h−1. In order to validate the developed method, several certified reference samples of environmental waters including sea water, were analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of inorganic arsenic in well-water and sea water.

Ultrasound-assisted supramolecular solvent microextraction coupled with graphite furnace atomic absorption spectrometry for speciation analysis of inorganic arsenic

A novel ultrasonic-assisted supramolecular solvent microextraction (USASS-ME) method was proposed for the selective microextraction of As(iii, v) prior to its determination via graphite furnace atomic absorption spectrometry.

Speciation analysis of inorganic arsenic in food and water samples by electrothermal atomic absorption spectrometry after magnetic solid phase extraction by a novel MOF-199/modified magnetite nanoparticle composite

A novel magnetic metal–organic framework (MOF-199/dithiocarbamate modified magnetite nanoparticles composite) was synthesized and utilized for speciation analysis of inorganic arsenic.

Determination of Inorganic Arsenic Speciation in Municipal Solid Waste Incineration Fly Ash by High Performance Liquid Chromatography-Hydride Generation-Atomic Fluorescence Spectroscopy with Phosphoric Acid as Extracting Agent

A method for the determination of arsenic speciation in municipal solid waste incineration fly ash was developed by high performance liquid chromatography (HPLC) coupled with hydride generation atomic fluorescence spectroscopy (HG-AFS). Before determination, various forms of arsenic were extracted with phosphoric acid through microwave digestion. The effect of phosphoric acid in the extracted solution on the speciation analysis of inorganic arsenic (As(III)/As(V)) was studied in detail. The results showed that when using diammonium phosphate as the mobile phase, the determination of As(V) was adversely affected. The increasing flow rate of mobile phase hardly reduced the adverse influence caused by phosphoric acid. The adverse influence was effectively suppressed when a mixed solution of disodium hydrogen phosphate/potassium dihydrogen phosphate (pH = 6.864) was used as the mobile phase. By using the improved method, As(III) and As(V) could be separated in 5 min, and the detection limits of As(III) and As(V) were 0.063 μg L−1 and 0.110 μg L−1, respectively. The recovery rate of As(III) and As(V) in spiked standard sample was satisfactory (86.9%–102.6%). The determination of arsenic species in fly ashes sampled from four different municipal solid waste incineration plants were successfully accomplished by using the method. The results showed that the arsenic was predominantly in the form of As(V).

Simultaneous speciation analysis of inorganic arsenic, chromium and selenium in environmental waters by 3-(2-aminoethylamino) propyltrimethoxysilane modified multi-wall carbon nanotubes packed microcolumn solid phase extraction and ICP-MS

Speciation analysis of inorganic arsenic, chromium and selenium in environmental waters is of great significance for the monitoring of environmental pollution. In this work, 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) functionalized multi-wall carbon nanotubes (MWCNTs) were synthesized and employed as the adsorbent for simultaneous speciation analysis of inorganic arsenic, chromium and selenium in environmental waters by microcolumn solid-phase extraction (SPE)-inductively coupled plasma mass spectrometry (ICP-MS). It was found that As(V), Cr(VI) and Se(VI) could be selectively adsorbed on the microcolumn packed with AAPTS-MWCNTs adsorbent at pH around 2.2, while As(III), Cr(III) and Se(IV) could not be retained at this pH and passed through the microcolumn directly. Total inorganic arsenic, chromium and selenium was determined after the oxidation of As(III), Cr(III) and Se(IV) to As(V), Cr(VI) and Se(VI) with 10.0μmolL−1 KMnO4. The assay of As(III), Cr(III) and Se(IV) was based on subtracting As(V), Cr(VI) and Se(VI) from the total As, Cr and Se, respectively. Under the optimized conditions, the detection limits of 15, 38 and 16ngL−1 with the relative standard deviations (RSDs) of 7.4, 2.4 and 6.2% (c=1µgL−1, n=7) were obtained for As(V), Cr(VI) and Se(VI), respectively. The developed method was validated by analyzing four Certified Reference Materials, rainwater, Yangtze River and East Lake waters.

Speciation analysis of inorganic arsenic in river water by Amberlite IRA 910 resin immobilized in a polyacrylamide gel as a selective binding agent for As(V) in diffusive gradient thin film technique.

In this study, a method is proposed for the selective retention of As(V) using diffusive gradient in thin film (DGT) samplers containing a strongly basic anion exchange resin (Amberlite IRA 910) supported on a polyacrylamide gel. In addition, the total arsenic content is determined by ferrihydrite gel discs. Subsequently, the concentration of As(III) was obtained by determining the difference between the total As and As(V). DGT experiments showed linear accumulation of As(V) (up to 280 ng) until a deployment time of 8 h deployment (R(2) > 0.99). The retention of As(V) was appropriate (97.9-112.3%) between pH 5 and 9. For a solution with an ionic strength ranging from 0.001 to 0.05 mol L(-1), the As(V) uptake ranged from 90-120%. The proposed method was applied for the speciation of arsenic in river water. For the analysis of spiked samples collected at the Furnas stream, the recoveries of total arsenic content ranged between 103.9% and 118.8%. However, the recoveries of As(III) and As(V) were 43.3-75.2% and 147.3-153.4%, respectively. These differences were probably because of the oxidation of As(III) to As(V) during deployments. For spiked samples collected at the Ribeirão Claro, the recoveries of dissolved As(III), As(V) and As(T) were 103.1%, 108.0% and 106.3%, respectively. Thus, the DGT technique with Amberlite IRA 910 resin as the binding phase can be employed for the in situ redox speciation of inorganic arsenic.

Simultaneous speciation analysis of As, Sb and Se redox couples by SF-ICP-MS coupled to HPLC

A new method for the simultaneous speciation analysis of inorganic arsenic (iii, v), antimony (iii, v) and selenium (iv, vi) using anion exchange column.

On-line speciation analysis of inorganic arsenic in complex environmental aqueous samples by pervaporation sequential injection analysis

A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L(-1) (3sblank level criterion), 50-1000 μg L(-1) and 3.0% at the 500 μg L(-1) level and for As(V) of 51 μg L(-1), 100-2000 μg L(-1) and 2.6% at the 500 μg L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).

Interface of on line coupling capillary electrophoresis with hydride generation electrothermal atomic absorption spectrometry and its application to arsenic speciation in sediment

A novel interface for on line coupling capillary electrophoresis with hydride generation electrothermal atomic absorption spectrometry (CE–HG–ETAAS) has been developed. The interface performance was examined in detail. The technique could be used to convert arsenic compounds from CE separation to corresponding volatile hydrides determined by HG–ETAAS. This paper aims to explore the best condition in the speciation analysis of inorganic arsenic by using CE–HG–ETAAS. The application of the developed CE–HG–ETAAS to inorganic arsenic speciation in sediment was investigated. The detection limits of As(III) and As(V) were 135ng/g and 160ng/g, respectively. Relative standard deviations of arsenic speciation were better than 2%. The recoveries of As(III) and As(V) in the sample with spiking concentration of 2500ng/g As(III) and 5000ng/g As(V) were 97.6% and 96.7%, respectively.

Speciation analysis of inorganic arsenic in coal samples by microwave-assisted extraction and high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry

A new method was developed for the speciation analysis of inorganic arsenic in coal samples by high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry after microwave-assisted extraction. Effective extract of As(III) and As(V) in coal sample was achieved by 1.0molL−1H3PO4 and 0.1molL−1ascorbic acid. Under the optimized conditions, the limits of detection (LOD) were 0.01μgL−1 and 0.02μgL−1, the relative standard deviations (RSD) were 2.4% and 3.3% (c=10.0μgL−1, n=7), recoveries were 102.5% and 96.5% for As(III) and As(V). The proposed method was successfully applied for the determination of speciation of inorganic arsenic in coal samples and GBW11117 coal standard reference material with complex matrix.

Field separation‐based speciation analysis of inorganic arsenic in public well water in Hungary

Twenty‐three water samples were collected from public wells from 3 different counties, having a history of high natural arsenic occurrence in Hungary, as well as in the resort area close to the capital city for speciation analysis of arsenic As(III) and As(V). In order to prevent interconversion of arsenic species in the samples, a simple field separation method was applied by using solid phase extraction anion exchange cartridges prior to the inductively coupled plasma sector field mass spectrometric analyses. Total arsenic level in the samples was confirmed to be higher than the health limit value established by the European Union (10μg×L−1) for drinking water in 22 samples. Thus, the total As concentration of the samples ranged between 7.2 and 210.3μg×L−1. According to the speciation study, two thirds of the samples contained As(V) in more than 60%. Beside the calculation of As(V)/As(III) ratios in the samples, the oxidative character of the geochemical environment could be suggested by determining the concentration of oxyanion‐forming elements (Mo, Se, U, V and W).

Speciation Analysis of Trace Inorganic Arsenic in Dietary Supplements by Slurry Sampling Hydride Generation Atomic Absorption Spectrometry

A new, rapid, and sensitive method was developed for speciation analysis of inorganic arsenic in dietary supplements using slurry sampling hydride generation atomic absorption spectrometry. As(III) content was determined under 1% HCl acidity conditions using both inhibitory effect of 8-hydroxyquinoline (8-HQ) on As(V) and its enhancing effect on As(III). Total inorganic arsenic content was determined under 5% HCl acidity conditions using the enhancing effect of 8-HQ on both As(III) and As(V). The method detection limit (S/N = 3) was 4.0 μg kg-1 for As(III) and 4.5 μg kg-1 for total inorganic arsenic. This method was validated using the Chinese standard method (GB/T 5009.11-2003), in good agreement with total inorganic arsenic content in real samples. The developed method was successfully applied to the speciation analysis of inorganic arsenic in dietary supplements with satisfactory results.