ETAAS Method Research Articles

Health Risks for Consumers of Forest Ground Cover Produce Contaminated with Heavy Metals.

The activity of heavy metal (HM) mining and processing industries causes soils contamination with HM. The metals could be transferred from contaminated soils to edible plants and fungi. This study aimed to assess the content of Cd, Pb, Hg, As, and Ni in berries and edible mushrooms collected in the forests located near Miasteczko Slaskie zinc smelter and in the Lubliniec region, in the context of consumers' health risk. The ET-AAS method was used to determine the content of Cd, Pb, Ni, and As. Mercury concentration was determined using the CV-AFS method. The studies showed high levels of Cd and Pb in the examined products. A statistically significant impact of the distance from the smelter on the Cd concentration in the berries was observed. Total non-cancer health risk from the combined exposure of adults to all HM in mushrooms and berries was significant when consuming the most heavily contaminated produce. The risk to children was significant, even when consuming products with moderate levels of the metals. Ingestion of Cd by children with mushrooms was related to a high cancer risk. The uncertainty of the results was determined. It is recommended to take action to increase awareness among residents of the areas adjacent to the forests regarding the existing health risk and to take possible measures to reduce exposure to HM.

Selective determination of rhodium and iridium in the urban environment using the catalytic method

The problem of studying the level of technogenic pollution of the environment with platinum group metals is attributed first to the release of platinum metals into the environment together with the exhaust gases of cars using afterburning catalysts containing Pt, Pd, Rh. The pharmaceutical, electronics and jewelry industries the waste of which contains PGMs also contribute to the pollution of the environment. A number of studies have shown the toxic effects of PGM on humans. The goal of the study is to obtain new information about the level of technogenic pollution of the environment with platinum group metals (such as water-washings from roads, bio-collector plants, roadside dust), which necessitates developing of the method for sample preparation and determination of rhodium and iridium. A technique of sample opening and determination of rhodium and iridium in environmental objects, water-washings from roads, bio-collector plants, roadside dust is proposed. To increase the selectivity of rhodium determination, the samples were treated with a mixture of concentrated perchloric acid and sodium periodate when heated to boiling, which provided more than 5-fold increase the rhodium signal. Moreover, the permissible excess of iridium and ruthenium was increased by 5 and 20 times, respectively, due to the conversion of other PGMs into catalytically inactive forms. The indicator reaction of sulfarsazen oxidation by periodate was used in the kinetic determination of rhodium and iridium. The correctness of the results obtained by the developed method was confirmed by the ETAAS method. The determined content of Rh and Ir: in roadside waters (μg/liter) up to 0.015 and 0.005; in collector plants (g/ton) up to 0.030 Rh and 0.022; in street dust (g/ton) up to 0.05 and 0.025, respectively. The standard deviation of the repeatability of the determination results does not exceed 0.07 (Rh) and 0.12 (Ir). The developed method of opening samples and determining rhodium and iridium in environmental objects provided a great bulk of information about the content of rhodium and iridium in water-flushes from Moscow roads, bio-collector plants, roadside dust, which correlate fairly well with the scarce data from other geographic regions available in the literature and our earlier results on rhodium content in dust. The developed technique made it possible to obtain data on the level of technical pollution of the environment with PGMs in places with different traffic density in Moscow.

Analysis of Nanomaterials Based on Indium and Zinc Oxides by High Resolution Atomic Absorption Spectrometry with the Use of Continuous Spectral Source and Electrothermal Atomization

The properties of nanostructured materials based on zinc and indium oxides can be modified by adding alloying elements to obtain the necessary electrical or optical properties. For example, the specificity of the chemical properties of ZnO and In2O3 for the determination of toxic gases is achieved by immobilizing Au, Ag, etc., nanoparticles on their surface. Control of the material composition plays an important role in determining the dependence between the dopant content and functional properties of the materials. The study is aimed at the development of a methodical approach to the multielement determination of catalytic dopants (Ag, Au) and matrix elements in nanostructured tin and indium oxides using the method of high resolution atomic absorption spectrometry with electrothermal atomization (ETAAS) and continuous spectral source. The matrix of the synthesized nanostructured materials is the corresponding oxide with possible oxygen deficiency due to the temperature conditions of the synthesis (300–700°C), and the content of additives (Ag, Au) is varied from 1 to 3 wt %. Optimal conditions of pyrolysis and atomization for sequential multielement analysis by the ETAAS method are determined. The optimal pyrolysis temperatures for determining Ag and Au (for both oxides), In, and Zn are 1000, 1600, 1200, and 900°C, respectively. The optimal atomization temperatures for determining Ag and Au (for nanomaterial based on indium oxide), Au (for nanomaterial based on zinc oxide), In, and Zn are 1800, 2200, 2100, 2200, and 1500°C, respectively. The accuracy of analyte determination reaches 1–4% (rel.). The correctness of the results is confirmed by inductively coupled plasma mass spectrometry. The developed method provides control of the composition of synthesized nanostructured materials for their more efficient use in photovoltaics, as well as in production of chemical sensors for detection of harmful compounds like CO, NO2, and NH3.

Use of ultrasound for cleaning of components of historical vehicles in Technical Museum in Brno

Abstract In the collections of Technical Museum in Brno, large number of historical vehicles is placed. During the operation, parts of their motors are being fouled. Frequently, they become even immobile (e. g. due to a fouled fuel system). In this case, the method using ultrasound with a suitable concentrate appears as the most suitable. In fact, ultrasound works also in inaccessible places with large efficiency. Not only the chosen solution influences the cleaning efficiency, but also parameters as time, bath temperature and ultrasound frequency. The cleaning process was evaluated according to the volume of removed dirt and by observing wettability change using the measuring of contact angle of a water drop. The ultrasound shock waves influence the surface to a certain extent also mechanically. That is why, the ultrasound effect on defects in the structure was observed. The aggressivity of cleaning concentrates was evaluated on the ground of determination of dissolved metals in the baths by ET AAS method.

A highly sensitive colorimetric assessment of hexavalent chromium using a digital camera.

Simple, low-cost, and sensitive methods for the assessment of hexavalent chromium as an important environmental pollutant are highly desirable, especially under resource-limited settings. Therefore, herein we propose an original approach for the simple, low-cost, selective, and extremely sensitive assessment of Cr(VI) utilizing its catalysis of the micellar sensitized o-dianisidine (DA)-hydrogen peroxide reaction. The initial rate of the amended reaction is monitored by tracing the oxidation product, either by a digital camera video recording or spectrophotometrically at 440 nm, for 120 s from mixing the reactants. The optimized reaction conditions were 5 mmol L-1 DA, 0.6 mol L-1 H2O2, 2.0 v/v% Tween 20, and 10 mmol L-1 chloroacetate buffer (pH 4.5 ± 0.1), at 30 °C. The linear calibration graph extends to 90.0 ng mL-1 Cr(VI) with detection limits (3Sb) of 0.8 and 1.0 ng mL-1, for the video recording and spectrophotometric procedures, respectively. The amended method was successfully applied to the assessment of Cr(IV) in natural and polluted industrial wastewaters. The analytical data were in excellent statistical harmony with those of the standard ETAAS method. The proposed method is two orders of magnitude more sensitive than the diphenylcarbazide standard spectrophotometric method.Graphical abstract.

ET AAS evaluation of the stability and pH-sensitivity of, pH-sensitive stealth liposomes containing cisplatin in mouse plasma

In this work, stability and the pH-sensitivity of pH-sensitive stealth liposomes containing cisplatin exposed to plasma medium and their subsequent responses to pH modifications were evaluated. A method to determine platin in mouse plasma by electrothermal atomic absorption spectroscopy (ET AAS) was developed and validated. At first, a comparative study of sample preparation treatments with basic, acidic, and acidic added with Triton X-100 as a modifier was done. The best treatment was obtained with HCl 3% (v/v). The ET AAS method with acid treatment presented linearity at a range of 10–160ng Pt/mL. The limits of detection (LOD) was 3.1ng/mL Pt for acid treatment, while the limit quantification (LOQ) was 10ng/mL Pt. The acid treatment presented good repeatability (VC<15.0%) and recovery close to 100%. This treatment was chosen for subsequent studies due to its best value of repeatability, recovery, LOD and lowest cost. pH-sensitive stealth liposomes, containing cisplatin, demonstrated low stability and poor response to pH variation after plasma incubation. These findings suggest that further studies are needed to improve liposome formulation i.e., to reduce its size.

Selective and sensitive speciation analysis of Cr(VI) and Cr(III) in water samples by fiber optic-linear array detection spectrophotometry after ion pair based-surfactant assisted dispersive liquid–liquid microextraction

A simple ion pair based-surfactant assisted dispersive liquid–liquid microextraction (IP-SA-DLLME) was evaluated for extraction and preconcentration of Cr(VI) and Cr(III) in aqueous samples. In this method, which was used for the first time for chromium speciation analysis, sodium dodecyl sulfate (SDS) was used as both ion-pairing and disperser agent. Cr(VI) ions were converted into their cationic complex with 1,5-diphenylcarbazide (DPC) and then extracted into 1-octanol dispersed in aqueous solution. Cr(III) ion also can be determined by this procedure after oxidation to Cr(VI). After extraction and phase separation, upper organic phase was transferred to a micro cell of a fiber optic-linear array detection spectrophotometry (FO-LADS). The effects of various parameters on the extraction recovery were investigated. Under the optimized conditions and preconcentration of 10mL of sample, the enrichment factor of 159 and the detection limit of 0.05μgL−1 were obtained. Validation of the method was performed by spiking-recovery method and comparison of results with those obtained by ET-AAS method.

Contamination, Fractionation and Availability of Metals in Urban Soils in the Vicinity of Former Lead and Zinc Smelters, France

Soil contamination by metals from anthropogenic activities (e.g., mining and smelting) is a major concern for the environment and human health. Environmental availability of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), and indium (In) in 27 urban soils located around two former Pb and Zn smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry (FAAS or ETAAS), depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical procedure. Metal partitioning was conducted using a four-step sequential extraction procedure. The results showed that Cd and Zn were mainly in the acid-extractable and reducible forms in the urban soils studied. In contrast, Pb and In were largely in the reducible fraction. However, in some samples, the amount of In extracted in the residual or exchangeable fraction was higher than that in the reducible fraction. Copper was mainly found in the reducible and residual fractions. A pot experiment was conducted in a glasshouse with seven soils (six contaminated and one uncontaminated) and two plant species, ryegrass and lettuce. The results showed transfer of metals from the contaminated soils to the shoots of ryegrass and the edible part of lettuce. The metal bioconcentration factor was in the order of Cd ≫ Cu > In > Zn ≫ Pb for lettuce leaves, whereas for ryegrass shoots, three orders were found, Cd > Zn > Cu ≫ In > Pb, Cd ≥ In > Zn > Cu ≫ Pb, and Zn > Cd > Cu > In > Pb, depending on the physico-chemical properties of the soils, such as pH, cation exchange capacity, carbonates, and organic matter. It was established that the metal toxicity was related to the contamination levels and the physico-chemical properties, including pH, organic matter, and in a lesser extent, Ca, Mg, and phosphorus contents, of the soils. However, it was shown that lettuce could grow on soils having high Cd and CaCO3 contents. Cadmium was one of the most available metals while Pb was always the least available in the soils studied.

Chromium speciation in environmental samples using a solid phase spectrophotometric method

A solid phase extraction technique is proposed for preconcentration and speciation of chromium in natural waters using spectrophotometric analysis. The procedure is based on sorption of chromium(III) as 4-(2-benzothiazolylazo)2,2′-biphenyldiol complex on dextran-type anion-exchange gel (Sephadex DEAE A-25). After reduction of Cr(VI) by 0.5ml of 96% concentrated H2SO4 and ethanol, the system was applied to the total chromium. The concentration of Cr(VI) was calculated as the difference between the total Cr and the Cr(III) content. The influences of some analytical parameters such as: pH of the aqueous solution, amounts of 4-(2-benzothiazolylazo)2,2′-biphenyldiol (BTABD), and sample volumes were investigated. The absorbance of the gel, at 628 and 750nm, packed in a 1.0mm cell, is measured directly. The molar absorptivities were found to be 2.11×107 and 3.90×107Lmol−1cm−1 for 500 and 1000ml, respectively. Calibration is linear over the range 0.05–1.45μgL−1 with RSD of <1.85% (n=8.0). Using 35mg exchanger, the detection and quantification limits were 13 and 44ngL−1 for 500ml sample, whereas for 1000ml sample were 8.0 and 27ngL−1, respectively. Increasing the sample volume can enhance the sensitivity. No considerable interferences have been observed from other investigated anions and cations on the chromium speciation. The proposed method was applied to the speciation of chromium in natural waters and total chromium preconcentration in microwave digested tobacco, coffee, tea, and soil samples. The results were simultaneously compared with those obtained using an ET AAS method, whereby the validity of the method has been tested.

Development and Validation of an ETAAS Method for the Determination of Tin in Canned Tomato Paste Samples

The determination of tin in canned food became very important in the last few years since it gives information about the contamination process helping to increase canned food quality and safety. The present work describes the development of a method for the determination of tin in canned tomato paste by electrothermal atomic absorption spectrometry in order to investigate the influents of (1) the industrial sample pretreatment procedure of canned tomato paste and (2) the type of materials used in packaging, on the total concentration of tin in canned tomato paste samples. For method validation, precision (repeatability and reproducibility) and accuracy (by recovery tests) have been assessed as performance criteria. The calculated recoveries ranged between 87.9% and 91.9%. The calculated expanded uncertainties based on the EURACHEM/CITAC Guidelines achieved from three different concentration levels were also calculated. The obtained results indicated that the method is efficiently and properly implemented. The validated method was applied for tin concentration determination in canned tomato paste purchased from the local market. In all analyzed samples, tin concentrations levels were lower than the maximum permissible value recommended by the European Regulation.

Evaluation of the ET-AAS and HG-AAS methods of selenium determination in vegetables

ET-AAS and HG-AAS methods of selenium determination were compared and evaluated. The ET-AAS method has been followed with deuterium background correction and Zeeman background correction respectively. The following validation parameters were determined: accuracy (under repeatability conditions), trueness, calibration curve and linearity, limit of detection, limit of determination and combined standard uncertainty of the method. The HG-AAS method and the ET-AAS method with Zeeman correction were more suitable for the determination of low selenium concentrations in vegetables. The results were calculated by the standard addition method because of the strong matrix effect.

Validation of an Electrothermal Atomization Atomic Absorption Spectrometry Method for Quantification of Total Chromium and Chromium(VI) in Wild Mushrooms and Underlying Soils

An ETAAS method was validated to quantify total Cr and Cr(VI) in mushrooms and the underlying soils. The method includes a sample pretreatment for total Cr dissolution using a wet acid digestion procedure and a selective alkaline extraction for Cr(VI). The limits of detection were, expressed in microg/L, 0.15 and 0.17 for total Cr and Cr(VI), respectively. The linearity ranges under the optimized conditions were 0.15-25.0 and 0.17-20.0 microg/L for total Cr and Cr(VI), respectively. The limits of quantification were, expressed in microg/g of dry weight, 0.0163 and 0.0085 for total and hexavalent chromium, respectively. The precision of the instrumental method for total Cr and Cr(VI) was lower than 1.6%, and for the analytical method, it was lower than 10%. The accuracy of the method for Cr(VI) quantification was evaluated by the standard additions method, with the recoveries being higher than 90% for all of the added concentrations. For total Cr, certified reference materials (lichen CRM 482 and soil sample NCS ZC73001) were used. An interference study was also carried out in a mushroom simulated matrix, and it was verified that the deviations of the expected values were lower than 4.0% for both total Cr and Cr(VI). The validated method was applied to the evaluation of total Cr and Cr(VI) in 34 wild mushrooms and 34 respective underlying soil samples collected in two different regions of Portugal (Beira Interior and TrAs-os-Montes), with different locations regarded as noncontaminated or contaminated areas. The species were identified by a mycologist and subdivided into 10 genera and 15 species: Amanita (rubescens, muscaria, and ponderosa), Boletus (regius), Lactarius (deliciosus, vellereus, and piperatus), Suillus (granulatus and luteus), Tricholoma (acerbum), Agaricus (sylvicola), Volvariella (gloiocephala), Lecopaxillus (giganteus), Macrolepiota (procera), and Psilocybe (fascicularis). The mean values found for total Cr were 1.14 and 1.11 microg/g of dry weight, and for Cr(VI), the mean values were 0.103 and 0.143 microg/g of dry weight for cap and stalk, respectively. For soils, the mean concentrations found were, for total Cr, 84.0 microg/g and, for Cr(VI), 0.483 microg/g. The bioconcentration factors (BCFs) based on dry weight for cap and stalk were determined, and the values found, for both total Cr and Cr(VI), were always <1, although for hexavalent chromium, the BCFs were 10 times higher than for total chromium.

Online Sample Pretreatment Systems for Determination of Cadmium by the ETAAS Method

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Online Sample Pretreatment Systems for Determination of Cadmium by the ETAAS Method

Trace and ultratrace determinations of cadmium in environmental and biological samples have become of increasing interest due to the high toxicity of this metal and because electrothermal atomic absorption spectrometry is probably the method of choice for its determination. The measured signals are, however, inherently very susceptible to the composition of the sample matrix and notably to variation within it. The most effective way to avoid these problems is to perform appropriate sample pretreatment such as preconcentration and separation. Such procedures are most advantageously performed in flow systems where all unit operations can be executed online. This paper reviews selected systems, such as solid-phase extraction, liquid-liquid extraction, coprecipitation and chemical vapor generation using to improve sample pretreatment for cadmium determination.

Slurry sampling electrothermal atomic absorption spectrometry for trace element analysis of high-purity tungsten trioxide

A slurry sampling ETAAS method for the determination of trace concentrations of Ca, Co, Cr, Cu, Fe, K, Mg, Na and Ni in tungsten trioxide is presented. A high background absorption appearing with large sample amounts during atomization at high temperatures was the only matrix interference observed. It could be significantly reduced by volatilization of the matrix in the pyrolysis step. Calibration curves recorded with aqueous standards could be used for calibration in all cases excluding the determination of very low analyte concentrations of Co and Fe which required the use of the standard additions method. The results obtained by this method showed an excellent agreement with those determined in digests by ETAAS. The detection limits achievable by the slurry technique were between 1 (Ca, K, Mg, Na) and 210 (Cu) ng/g. They were mostly by more than one order of magnitude better than those of the solution techniques.

ICP-OES Determination of Trace Ga,In,Bi,Sn and Pb Preconcentrated by Macroporous Poly(Vinylethylenediamine) Chelating Resin1

Abstract An ICP-OES method for applying a macroporous ploy(vinylethy-lenediamine) chelating resin to preconcentrate and separate trace Ga(III), In(III), Bi(III), Sn(IV) and Pb(II) ions from solution samples is established. The analyzed ions of 0.05–0.5 ug/ml can be enriched by the resin of 0.07-g amount at a 1.0 ml/min of flow rate at pH 5, and can be also desorbed with a 10 ml of 3 M HClO4 from the resin column, with recoveries over 96%. The chelating resin reused 7 times can still adsorb quantitatively the Ga, In, Bi, Sn and Pb ions, and a 500-fold excess of Fe(III), Al(III), Mn(II), Cu(II), Ni(II), Zn(II) and Cr(III) caused little interference with the enrichment and determination of these ions. The RSDs of the proposed method are in the range 1.2–5.5% for each analyzed ion. The recoveries of added standard in real solution samples are between 94% and 100%, and the concentration of each ion in a mineral sample detected by the method is in good agreement with the analyzed value by ETAAS method. 1The sub...

Extraction–atomic absorption spectrometric method for the determination of the platinum group elements and gold in copper–nickel ores using an autoclave sample decomposition technique

An ETAAS method was developed to determine the platinum group elements and gold in copper–nickel ores using a single sample. It is based on an approach involving interconnected consideration of the main components of analytical procedure (autoclave decomposition of sample; collective extractive preconcentration of metals with a mixture of alkylaniline hydrochloride and petroleum sulfides; and atomic absorption spectrometric analysis of the extract). The concentrations of elements determined in standard reference materials (lode and impregnation copper–nickel sulfide ores) were found to be in accordance with the certified values, within experimental error. The relative standard deviation varied between 2 and 17% at 0.05–10 mg kg–1 element concentrations. The determination limits were 0.001–0.06 mg kg–1 for a 5 g sample and an extract volume of 5 ml.

Chemical modifier methods for the determination of bismuth and silver in nickel-based alloys and steels by Zeeman electrothermal atomization

A reliable ETAAS method for determining trace amounts of silver and bismuth in a wide range of nickel superalloys and steels has been developed. This uses a single matrix calibration based on nickel and suitable chemical modifiers, such as hafnium and tartaric acid for bismuth and ammonium dihydrogen phosphate for silver. Detection limits are 0.06 µg dm–3 for silver and 1 µg dm–3 for bismuth. The method allows a wide range of alloy types to be analysed from a common set of calibration standards, which considerably simplifies and shortens the analysis.

Distribution of mercury in the open‐sea region of the South‐Western Black Sea

Data of mercury content in the south‐western Black Sea are presented. The chemical analysis is performed by ETAAS method. The spatial distribution and the concentration levels for different sampling locations are graphically summarized and discussed.

Platform atomization in the electrothermal AAS determination of magnesium in gallium arsenide

An ET-AAS method using platform atomization is proposed for the determination of magnesium in gallium arsenide. The sample is decomposed with nitric and hydrochloric acids and the diluted solution is injected into the furnace. No significant interferences from the matrix up to 4.0 mg GaAs ml−1 were observed by using the proposed procedure. The detection limit (3 σ) is 0.12 μg Mg g−1 in GaAs. Improvements should be achieved by a better control of contamination sources. Results obtained by analysing undoped GaAs samples are presented.