Separation Of Inorganic Arsenic Species Research Articles

A simple and rapid copper-assisted microprecipitation method for the on-site separation of inorganic arsenic species in water samples followed by hydride generation atomic fluorescence spectrometry determination

A simple and rapid microprecipitation procedure was developed using copper (Cu2+) as precipitating agent for the separation–preconcentration of inorganic arsenic species (As(III) and As(V)) in waters prior to their determination by hydride generation atomic fluorescence spectrometry (HG-AFS). This procedure is based on selective precipitation of anionic species of As(V) with Cu2+, leaving neutral As(III) in the filtrate. The complexation of As(V) with Cu(II) entails the precipitation as copper arsenate, Cu3(AsO4)2 due to its low solubility product. The copper arsenate precipitate was characterized by XRD and EDS measurements. Optimum conditions for efficient microprecipitation process are; pH: 5 to 6, Cu/As mass ratio: 100, equilibration time: 2–3 min and eluent volume: 2 mL of 0.03 mol L−1 HCl. A fast process time of 2 min is enough for the on-site separation of As(III) and As(V) with the detection limits (LOD) 0.012 and 0.034 μg L−1 respectively. The recoveries were found to be in the range of 98–102%. This simple and fast method was successfully utilized for the on-site separation of As(III) and As(V) in wide variety of water samples collected in and around Kiradalli Tanda village, Karnataka state, India, where severe arsenic-contamination exists in various water bodies.

Adsorption Separation of Arsenic(III) and Arsenic(V) using Functionalized Silica Gels

A method for the adsorption separation of inorganic arsenic species (As(III)/As(V)) using sequentially connected preconcentrating columns filled with functionalized silica gels and their determination by inductively coupled plasma optical emission spectrometry was proposed. As(V) was effectively retained at pH 3.5–6.5 by an adsorbent containing groups of quaternary phosphonium bases on the surface and exhibiting the properties of an anion exchanger. In this pH range, As(III) was not extracted, which made it possible to separate As(V) from As(III). As(III) was retained in a wide pH range of 1–6 by a complexing adsorbent containing mercapto groups on the surface. Adsorbed As(V) was quantitatively eluted from the surface with 1M HNO3, and As(III) – with 5 % unithiol solution in 2M HCl. The use of «non-aggressive» eluents allows us to reuse adsorbents for preconcentration of As(III) and As(V) at least 5 times. The separation efficiency was confirmed by the analysis of model solutions

Application of μ-TLC for speciation of inorganic arsenic by laser ablation inductively coupled plasma mass spectrometry

A novel µ-Thin layer Chromatography coupled with Laser Ablation Inductively coupled Plasma Mass Spectrometry method based on Ion Imprinted Polymer (IIP) is developed for the first time in this paper which tries to investigate the separation of inorganic arsenic species in aqueous media. Surface morphology, functionality, and bulk composition of the as-synthesized copolymer were confirmed utilizing multiple techniques, such as XRD, FESEM, and FT-IR. IIP-Copolymer was combined with CaSO4, as a binder agent, that was used to prepare a thin layer chromatography plate. Subsequently, inorganic arsenic species were separated over the TLC plate based on As(V)-imprinted polymer. In the following, the plate surface was scanned via laser ablation which volatilized the inorganic arsenic species from the TLC plate and then introduced them to the ICP-MS system. The effect of some experimental conditions including pH, mobile phase composition, and IIP/CaSO4 mass ratio on the separation efficiency were also investigated. Moreover, the obtained results for the spiked inorganic arsenic species in real samples, such as Angouran, Nakhlak, and Zarshouran proved that the methods were practically applicable to speciation analysis. Under the established optimal condition, the detection limit, Relative Standard Deviation (RSD) of responses, and linear dynamic range (LDR) of the method were obtained as 0.3 μg L−1, 3.8%, and 0.2–100 μg L−1 for As(V) assay. The IIP-µTLC/LA-ICP-MS has also illustrated great application perspectives for rapid and high-effective selection, characterization, and separation of ultra-trace inorganic arsenic species in environmental water samples.

Development of a method for speciation of inorganic arsenic in waters using solid phase extraction and electrothermal atomic absorption spectrometry

ABSTRACTA solid phase extraction (SPE) procedure based on Amberlite IRA 900 resin was developed for speciation and separation of inorganic arsenic species (III, V) and total As in water samples. The As species and total As in eluent solutions were determined by electrothermal atomic absorption spectrometry (ETAAS) using Ni chemical modifier with 1200°C pyrolysis temperature. Experimental parameters such as pH value, sample volume, flow rate, volume and concentration of eluent solution for As(V) were optimised and 98.0 ± 1.9% recovery was found at pH 4.0. Experimental adsorption capacity of the resin for As(V) was investigated and 229.9 mg g–1 was found. Under optimised experimental conditions, instrumental parameters such as limit of detection (LOD) and limit of quantification (LOQ) found were 0.126 and 0.420 µg L–1, respectively. Interference effects of coexisting ions in the sample matrix on the recovery of As(V) were investigated. Concentration of As(III) was obtained by subtracting As(V) concentration found at pH 4.0 from total As(III + V) found at pH 8.0. The accuracy of the method proposed by using the resin was tested for analysing As species in a waste water standard reference material (SRM, CWW-TM-D) and spiked real water samples with recovery above 95%. The method proposed was also applied to the determinations of As species and total As in underground hot waters and tap water with relative error below 3%.

Separation of Inorganic Arsenic Species from Aqueous Solution by Anion Exchange Column and Its Application in Study of Arsenic Removal

Separation of Inorganic Arsenic Species from Aqueous Solution by Anion Exchange Column and Its Application in Study of Arsenic Removal

Speciation analysis of inorganic arsenic in natural water by carbon nanofibers separation and inductively coupled plasma mass spectrometry determination

In this paper, carbon nanofibers (CNFs) as a novel solid phase extraction sorbent were developed for speciation preconcentration and separation of inorganic arsenic species As(III) and As(V) prior to determination by inductively coupled plasma mass spectrometry (ICP-MS). It was found that during all the steps of the separation, As(III) was selectively sorbed on the microcolumn packed with CNFs within a pH range of 1.0–3.0 in the presence of ammonium pyrroinedithiocarbamate (APDC), while As(V) was passed through the microcolumn without the retention. Various experimental parameters affecting the separation and determination of As(III) and As(V) have been investigated in detail. Under the optimized conditions, the detection limits of this method for As(III) were 0.0045 ng mL −1 with an enrichment factor of 33 and 0.24 ng mL −1 for As(V), and the relative standard deviations for As(III) and As(V) were 2.6% and 1.9% ( n = 9, c = 1.0 ng mL −1), respectively. In order to verify the accuracy of the method, a certified reference of water sample was analyzed, and the results obtained were in good agreement with the certified values. The proposed method was applied for the analysis of inorganic arsenic species in groundwater and lake water with the recovery of 92–106%.

A reactor/phase separator coupling capillary electrophoresis to hydride generation and inductively coupled plasma optical emission spectrometry (CE-HG-ICP OES) for arsenic speciation

The separation of inorganic arsenic species by capillary electrophoresis, CE, and the post column on line arsine generation was performed in a homemade system coupled to an inductively coupled plasma optical emission spectrometer. CE was coupled with a hydride generation reactor/phase separator using a T interface. The hydrides were formed and separated in a device constructed with a 10 ml syringe. Capillary dimensions, flow-rates and connection arrangements were optimised to avoid backpressure in the electrophoresis capillary and to attain good resolution of the enlarged peaks. The CE-HG-ICP signals for As(III) and As(V) presented a peak area increase of a factor around 40 compared with those attained using the direct CE-ICP.

Separation of Inorganic Arsenic Species in Groundwater Using Ion Exchange Method

Separation of Inorganic Arsenic Species in Groundwater Using Ion Exchange Method

Separation of inorganic arsenic species in groundwater using ion exchange method.

Separation of inorganic arsenic species in groundwater using ion exchange method.

Separation of organic and inorganic arsenic species by capillary zone electrophoresis

Capillary zone electrophoresis has been used to separate arsenite, arsenate, dimethylarsinic acid, and phenyl-,p-aminophenyl-, ando-aminophenylarsinic acids. Identification and quantification of the arsenic species at mg L−1 levels was possible by use of direct UV detection at 200 nm. The relative standard deviation (n=7) ranged from 0.97 to 1.52% for migration times and from 2.08 to 4.31% for peak areas. A method for rapid separation of inorganic arsenic species was also developed; by use of this method arsenite and arsenate could be separated within 2 min.