scholarly journals Separation and determination of dimethylarsenate in natural waters

2012 ◽  
Vol 77 (6) ◽  
pp. 775-788 ◽  
Author(s):  
Issa Ben ◽  
Aleksandar Marinkovic ◽  
Ljubinka Rajakovic
Keyword(s):  
Natural Waters ◽  
Ph Value ◽  
Fixed Bed ◽  
Inorganic Arsenic ◽  
Standard Addition ◽  
Arsenic Species ◽  
Arsenic Adsorption ◽  
Strong Base ◽  
Relative Standard

A simple and efficient method for separation and determination of dimethylarsenate DMAs(V) was developed in this work. Two resins, a strong base anion exchange (SBAE) resin and iron-oxide coated hybrid (HY) resin were tested. By simple adjusting pH value of water at 7.00, DMAs(V) passed through the HY column without any changes, while all other arsenic species [inorganic arsenic and monomethylarsonate, MMAs(V)] were quantitatively bonded on HY resin. The resin capacity was calculated according to the breakthrough points in a fixed bed flow system. At pH 7.00 the HY resins bonded more than 4150 ?g g-1 of As(III), 3500 ?g g-1 of As(V) and 1500 ?g g1 of MMAs(V). Arsenic adsorption behavior in the presence of impurities showed tolerance with the respect to potential interference of anions commonly found in natural water. DMAs(V) was determined in the effluent by ICP-MS. The detection limit was 0.03 ?g L?1 and relative standard deviation (RSD) was between 1.1?7.5 %. Proposed method was established performing standard procedures: with external standard, certified reference material and the standard addition method.

Determination of inorganic arsenic species in natural waters—Benefits of separation and preconcentration on ion exchange and hybrid resins

2010 ◽  
Vol 673 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Nureddin Ben Issa ◽  
Vladana N. Rajaković-Ognjanović ◽  
Branislava M. Jovanović ◽  
Ljubinka V. Rajaković
Keyword(s):  
Ion Exchange ◽  
Natural Waters ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Separation And Preconcentration ◽  
Inorganic Arsenic Species

Cathodic Stripping Voltammetric Study for Determination of Inorganic Arsenic Species in Seaweed Gracilaria fisheri

2019 ◽  
Vol 886 ◽  
pp. 78-85
Author(s):  
Charuwan Khamkaew ◽  
Lalitporn Wongsuwan ◽  
Abdullateep Sareedeh
Keyword(s):  
Inorganic Arsenic ◽  
Stripping Voltammetry ◽  
Arsenic Species ◽  
Deposition Efficiency ◽  
Relative Standard ◽  
Inorganic As ◽  
Inorganic Arsenic Species ◽  
Deposition Step ◽  
Cathodic Stripping

A simple, rapid, selective and sensitive square wave cathodic stripping voltammetry (SWCSV) at a hanging mercury drop electrode (HMDE) for the determination of As(III), As(V) and inorganic As(total) in seaweed was developed. The method was based on the formation of copper-arsenic intermetallic compound in the presence of HCl onto a HMDE at a constant potential of -0.40 V vs. Ag/AgCl in the deposition step, followed by the reduction of deposited compound to arsine at a potential of -0.78 V in the stripping step. In the system, only As(III) was directly measured, whereas inorganic As(total) was measured by reducing As(V) to As(III) using thiosulfate. In the deposition step, the use of 10 mg L-1 Cu(II) and 1 M HCl was recommended for the determination of 2 µg L-1 As(III) under the optimum instrumental variables obtained at 150 s for deposition time and 2000 rpm for stirring speed with the highest deposition efficiency of 16.15 and 88.49%, respectively. In the determination of As(V), two values of the highest reduction efficiency obtained using concentration of 40 mg L-1 thiosulfate, and reducing time at 300 s were 98.15% and 37.89%, respectively. In the measurement, the quantification limits of As(III) and As(V) were 0.46, and 1.62 µg L-1, respectively. The relative standard deviation (n=10) for 2 ug L-1 As(III) and As(V) were 5.20% and 2.57%, respectively. The proposed method was applied to the determination of inorganic arsenic species in seaweed Gracilaria fisheri.

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

scholarly journals Analysis of the Chloroacetanilide Herbicides in Water Using SPME with CAR/PDMS and GC/ECD

2005 ◽  
Vol 88 (4) ◽  
pp. 1236-1241 ◽  
Author(s):  
Ying-Ming Hwang ◽  
Yih-Gang Wong ◽  
Wu-Hsiung Ho
Keyword(s):  
Humic Acid ◽  
Ph Value ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Standard Addition ◽  
Electron Capture Detection ◽  
Detection Analysis ◽  
Salt Addition ◽  
Chloroacetanilide Herbicides ◽  
Relative Standard

Abstract The solid-phase microextraction (SPME) technique using a 75 mm film of carboxen/polydimethylsiloxane was applied to the analysis of chloroacetanilide herbicides (acetochlor, alachlor, butachlor, metolachlor, and propachlor) residues. The feasibility of SPME with gas chromatography electron capture detection analysis has been evaluated. The effects of experimental parameters such as magnetic stirring, salt addition, humic acid addition, pH value, and extraction time, as well as desorption temperature and time, were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The inhibition of humic acid to the extraction of chloroacetanilide herbicides was observed. A standard addition method for calibration was recommended to reduce deviations caused by matrix interferences. The proposed method provided a simple and rapid analytical procedure for chloroacetanilide herbicides in water with limits of detection 0.002–0.065 μg/L for deionized water, and 0.005–0.22 μg/L for farm water. The relative standard deviations (n = 5) for analyses of farm water were 7–20% for 0.5 μg/L chloroacetanilide herbicides. This application was illustrated by the analysis of sample collected from farm water in the Chung-hwa area, Taiwan.

scholarly journals Determination of Platinum in Wine by Graphite Furnace Atomic Absorption Spectrometry

1997 ◽  
Vol 80 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Carmen Cabrera-Vique ◽  
Pierra-Louis Teissedre ◽  
Marie-Thérèse Cabanis ◽  
Jean-Claude Cabanis
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Graphite Furnace ◽  
Standard Addition ◽  
Absorption Spectrometry ◽  
Acid Digestion ◽  
White Wines ◽  
Relative Standard ◽  
Graphite Furnace Atomic Absorption

Abstract A method based on graphite furnace atomic absorption spectrometry (GFAAS) was developed for determining platinum in wine. Wine samples were prepared by microwave acid digestion or dry mineralization. The method of standard addition was used for Pt determination in untreated wine samples and mineralized samples. Analyte modifiers and furnace conditions were optimized. Effects of cations (Mg2+, Ca2+, K+, Na+, and NH|) and anions (PO43, SO42) were tested separately and in combination. Analytical characteristics of the method were optimized for analyte recovery and signal enhancement. Recoveries ranged from 92.5 to 102%, and precision reproducibility relative standard deviation varied from 7.5 to 10%. Red, rosé, and white wines from France were analyzed. Platinum levels found in most wines were very low (<10 μg/L).

Contribution of organic arsenic species to total arsenic measurements using ferrihydrite-backed diffusive gradients in thin films (DGT)

2012 ◽  
Vol 9 (1) ◽  
pp. 55 ◽  
Author(s):  
Heléne Österlund ◽  
Mikko Faarinen ◽  
Johan Ingri ◽  
Douglas C. Baxter
Keyword(s):  
Thin Films ◽  
Natural Waters ◽  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Speciation Analysis ◽  
Arsenic Species ◽  
Future Studies ◽  
Organic Arsenic ◽  
Arsenic Determination ◽  
Diffusive Gradients

Environmental contextBoth the mobility and toxicity of arsenic in natural waters are related to the aqueous species distribution. Passive sampling using ferrihydrite-backed diffusive gradients in thin films (DGT) devices has in previous studies been characterised to measure labile inorganic arsenic, and the possible contribution of organic species has been disregarded. This study shows that the two most prevalent organic arsenic species might be included in DGT measurements, which should be taken into consideration when evaluating DGT data in future studies. AbstractIn previous publications discussing arsenic determination using ferrihydrite-backed diffusive gradients in thin films (DGT) devices, organic arsenic forms have been disregarded, even though it is known that the two most prevalent in natural waters, dimethylarsinate (DMA) and monomethylarsonate (MMA), may adsorb to ferrihydrite and thereby be included in the measurement. In this work the accumulation of DMA and MMA, as well as inorganic arsenite and arsenate, to ferrihydrite-backed DGT devices was investigated. It could be demonstrated that MMA, and under acidic conditions also DMA, adsorbed to the binding layer and might therefore contribute to the total mass of measured arsenic. Diffusion coefficients were measured for all four species to enable quantification of DGT-labile concentrations of organic and inorganic arsenic. Elution of the analytes from the ferrihydrite binding layer was performed using 1 mL of 1 M NaOH to facilitate arsenic speciation analysis using chromatographic separation. Average recovery rates were between 87 and 108 %. This study shows that the contribution of DMA and MMA to the total accumulated mass must be taken into consideration when evaluating DGT data in future studies.

scholarly journals Effect of arsenosugar ingestion on urinary arsenic speciation

1998 ◽  
Vol 44 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Mingsheng Ma ◽  
X Chris Le
Keyword(s):  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Sample Pretreatment ◽  
Arsenic Species ◽  
Urine Samples ◽  
Standard Reference Materials ◽  
Dimethylarsinic Acid ◽  
Urinary Arsenic ◽  
Biomarkers Of Exposure

Abstract We developed and evaluated a method for the determination of μg/L concentrations of individual arsenic species in urine samples. We have mainly studied arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) because these are the most commonly used biomarkers of exposure by the general population to inorganic arsenic and because of concerns over these arsenic species on their toxicity and carcinogenicity. We have also detected five unidentified urinary arsenic species resulting from the metabolism of arsenosugars. We combined ion pair liquid chromatography with on-line hydride generation and subsequent atomic fluorescence detection (HPLC/HGAFS). Detection limits, determined as three times the standard deviation of the baseline noise, are 0.8, 1.2, 0.7, and 1.0 μ/L arsenic for arsenite, arsenate, MMAA, and DMAA, respectively. These correspond to 16, 24, 14, and 20 pg of arsenic, respectively, for a 20-μL sample injected for analysis. The excellent detection limit enabled us to determine trace concentrations of arsenic species in urine samples from healthy subjects who did not have excess exposure to arsenic. There was no need for any sample pretreatment step. We used Standard Reference Materials, containing both normal and increased concentrations of arsenic, to validate the method. Interlaboratory studies with independent techniques also confirmed the results obtained with the HPLC/HGAFS method. We demonstrated an application of the method to the determination of arsenic species in urine samples after the ingestion of seaweed by four volunteers. We observed substantial increases of DMAA concentrations in the samples collected from the volunteers after the consumption of seaweed. The increase of urinary DMAA concentration is due to the metabolism of arsenosugars that are present in the seaweed. Our results suggest that the commonly used biomarkers of exposure to inorganic arsenic, based on the measurement of arsenite, arsenate, MMAA, and DMAA, are not reliable when arsenosugars are ingested from the diet.

scholarly journals Voltammetric Determination of Phenylalanine Using Chemically Modified Screen-Printed Based Sensors

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 113
Author(s):  
Ancuta Dinu ◽  
Constantin Apetrei
Keyword(s):  
Prussian Blue ◽  
Direct Determination ◽  
Standard Addition ◽  
Pharmaceutical Products ◽  
Electrochemical Process ◽  
Pharmaceutical Samples ◽  
Analytical Recovery ◽  
Relative Standard ◽  
Screen Printed

This paper describes the sensitive properties of screen-printed carbon electrodes (SPCE) modified by using three different electroactive chemical compounds: Meldola’s Blue, Cobalt Phthalocyanine and Prussian Blue, respectively. It was demonstrated that the Prussian Blue (PB) modified SPCE presented electrochemical signals with the highest performances in terms of electrochemical process kinetics and sensitivity in all the solutions analyzed. PB-SPCE was demonstrated to detect Phe through the influence it exerts on the redox processes of PB. The PB-SPCE calibration have shown a linearity range of 0.33–14.5 µM, a detection limit (LOD) of 1.23 × 10−8 M and the standard deviation relative to 3%. The PB-SPCE sensor was used to determine Phe by means of calibration and standard addition techniques on pure samples, on simple pharmaceutical samples or on multicomponent pharmaceutical samples. Direct determination of the concentration of 4 × 10−6–5 × 10−5 M Phe in KCl solution showed that the analytical recovery falls in the range of 99.75–100.28%, and relative standard deviations in the range of 2.28–3.02%. The sensors were successfully applied to determine the Phe in pharmaceuticals. The validation of the method was performed by using the FTIR, and by comparing the results obtained by PB-SPCE in the analysis of three pharmaceutical products of different concentrations with those indicated by the producer.

Sign in / Sign up

Export Citation Format

Share Document