Simultaneous determination of major, minor and trace elements in airborne particulates by inductively coupled plasma-atomic emission spectroscopy

Summary A method for the simultaneous multi-element determination of major, minor and trace elements in airborne particulates by ICP-AES was proposed based on multi-acid digestion. The methods for sample decomposition under high and ambient pressure were compared using a mixture of nitric, perchloric and hydrofluoric acids. The ambient pressure technique was finally adopted. Spectral interferences were taken into account and corrected. A recovery study was conducted for most of the elements, and a good agreement was obtained with the certified values of NBS SRM 1648 urban particulate materials using the recommended method.

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Simultanbestimmung von Haupt-, Neben- und Spurenbestandteilen in atmosphärischen Teilchen durch ICP-AES

Zusammenfassung Das Verfahren beruht auf dem Aufschluß mit einem Säuregemisch (Salpeter-, Perchlor-, Flußsäure) bei normalem Druck. Ein Druckaufschluß wurde ebenfalls geprüft, war jedoch weniger geeignet. Störungen wurden durch Korrekturen berücksichtigt. Im Vergleich mit einem Standard-Referenzmaterial wurde befriedigende Übereinstimmung erzielt.

     

Preconcentration and determination of trace elements with 2-aminoacetylthiophenol functionalized Amberlite XAD-2 by inductively coupled plasma-atomic emission spectrometry

2-Aminoacetylthiophenol (AATP)-modified Amberlite XAD-2 has been synthesized by coupling it through NNNH group. The resulting chelating resin, characterized by elemental analysis, thermogravimetric analysis (TGA) and infrared (IR) spectra, was used to preconcentrate Cd, Hg, Ag, Ni, Co, Cu and Zn ions. Several parameters, such as distribution coefficient and sorption capacity of the chelating resin, pH and flow rates of uptake and striping, volume of sample and eluent, were evaluated. The effects of electrolytes and cations on the preconcentration were also investigated. The recoveries were >96%. The procedure was validated by standard addition and analysis of a standard reference sediment material (GBW 07309 China). The developed method was utilized for preconcentration and determination of Cd, Hg, Ag, Ni, Co, Cu and Zn in tap water, river water and sediment samples by inductively coupled plasma-atomic emission spectrometry (ICP-AES) with satisfactory results. The 3σ detection limits for Cd, Hg, Ag, Ni, Co, Cu and Zn were found to be 0.10, 0.23, 0.41, 0.13, 0.25, 0.39 and 0.58 μg l⁻¹, respectively. The relative standard deviation of the determination was <10%.     

Method validation for direct determination of some trace and toxic elements in soft drinks by inductively coupled plasma mass spectrometry

The consumption of soft drink beverages has increased in the last few years around the world and it is related to the diversity of brands and flavours available, increasing also the risk of ingestion of compounds considered non-beneficial to the health of consumers. In this study, fast, easy and simple method of analysis for direct determination of As, Pb, Cd, Sb, Hg, Cu, Zn, Fe, Al, Cr, Sn, Co, Mn and Ni in soft drink samples using quadrupole inductively coupled plasma mass spectrometry (Q-ICP–MS) was validated. The estimated detection limits, practical quantification limits, linearity (linear dynamic ranges and method linearity), accuracy (trueness and precision) and measurement uncertainty parameters were studied under optimised (Q-ICP–MS) conditions. The method showed that the estimated detection limits were varied between 0.02 and 2.403 µg/L, and the quantification limits were varied between 0.5 and 20 µg/L. The mean recoveries ± standard deviations at different spiking levels were varied between 75.03 ± 0.62% and 117.07 ± 2.83% and the coefficients of variation were varied between 0.49% and 9.79%. The method trueness was confirmed by using four different certified reference materials (soft drinks and treated water) purchased from FAPAS (Food Analysis Performance Assessment Scheme) and all obtained results were within satisfactory ranges and had acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation, was below 4.88%. The method uncertainty expressed as expanded uncertainty of all validated elements was found to be ≤22.52%. The results obtained make the method suitable for accurate determination of validated elements in different kinds of soft drink samples at these low concentration values. Validated method was used for the determination of metallic contaminants in 40 commercial soft drink samples and the results were compared with the provisional guideline of the elements stated by Egyptian, WHO and European standards in drinking and potable bottled natural mineral water.     

Development and characterization of bottom-viewed inductively coupled plasma-atomic emission spectrometry

In bottom-viewed inductively coupled plasma-atomic emission spectrometry (BV-ICP-AES), emission from the central channel of the plasma is measured axially from the bottom of the plasma. A straight quartz tube was used as a hollow light pipe (HLP) to collect plasma emission in this study. The HLP also serves as an injector for aerosols transport and injection into the ICP. The optical characteristics of HLPs with the original reflective surface and roughened outer surface are reported. The roughened HLP is effective in rejecting light beams that are not in line with the HLP. The transmission efficiency of the HLP, however, is high (> 70%) for light beams from a source that has the same dimension as the entrance of the HLP and is flush with the HLP. The HLP is effective in rejecting background emission from the core of the plasma that encircles the plasma central channel and yet efficient in light collection from the central channel of the plasma.     

电感耦合等离子体原子发射光谱法测定自来水中的8种元素

采用电感耦合等离子体原子发射光谱法(ICP-AES)测定了化学实验室自来水中铝、钾、锶、钡、锰、钴、钼、硒8种元素的含量;对仪器的工作条件进行了优化,确定了各元素的分析波长和检出限.结果表明,所述方法可以方便地用于测定化学实验室自来水样品中的8种元素,相对标准偏差为0.08%～6.90%.     

Preconcentration of trace elements on a support impregnated with sodium diethyldithiocarbamate prior to their determination by inductively coupled plasma-atomic emission spectrometry

A procedure is developed for determination of As, Co, Se, Cr, Pb, Zn, Cu, Mn, Cd, Sb, and Sn in water by ICP-AES analysis of alcohol eluates after pre-concentration of the samples. The pre-concentration is performed on a sodium diethyldithiocarbamate supported soft polyurethane foam. The sorbed elements are subsequently eluted with 1-propanol and the alcohol eluates are analysed by ICP-AES. A eight-fold concentration is achieved. An increased sensitivity in the analysis of propanol-water (30:70, v/v) solution is established as compared with aqueous solutions. The strongest effect is observed for As, Se, Pb, Cr, Sn, and Cd-increasing is more than twice. For other elements the matrix influence is by a factor of 1.45 (Cu), 1.36 (Sb), 2.08 (Zn). The method is applied to the analysis of natural water samples.     

High-throughput determination of seven trace elements in food samples by inductively coupled plasma-mass spectrometry

A method was developed for high-throughput determinations of 7 elements in food samples, namely antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and tin (Sn). The samples were digested by closed-vessel microwave-assisted digestion using concentrated nitric acid (HNO3) as the medium, followed by microwave- assisted evaporation to concentrate the sample solutions before dilution to the desired volume. The microwave-assisted evaporation procedure effectively reduced the final acid concentration to around 8% before analysis by inductively coupled plasma-mass spectrometry (ICP-MS). This reduction allows determination by ICP-MS to proceed without further sample dilution, which would affect the detection limit. The method was validated, and method recoveries for As, Cd, Cr, Pb, and Hg were within the certified ranges of the chosen certified reference materials. Recoveries of the 7 elements from spiked samples ranged from 93.1 to 103.6%. The standard uncertainties of precision for the 7 elements were between 3.1 and 4.3%. Interlaboratory comparison studies for As, Cd, and Pb gave z-scores ranging from -0.2 to 0.3.     

Simultaneous determination of major,minor and trace elements in biocarbonates by inductively coupled plasma mass spectrometry

A method was developed for simultaneous determination of major (Ca), minor (Mg and Sr) and trace (Ba and U) elements in biocarbonates by inductively coupled plasma mass spectrometry (ICP-MS). The method precision (RSD%) is 0.73% for Ca, 0.77% for Mg, 0.59% for Sr, 2.02% for Ba, 1.13% for U, 0.67% for Mg/Ca, 0.27% for Sr/Ca, 2.06% for Ba/Ca and 1.23% for U/Ca. The ratio precision suggests that ICP-MS is satisfactory for obtaining multi-ratio data from biocarbonates. This technique was applied to 67 continuous coral samples.     

Erbium determination in preforms of optical fibres by inductively coupled plasma-atomic emission spectrometry

Erbium which is used in the composition of heavy metal fluoride optical fibres was determined in preforms of these materials by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The new analytical procedure developed comprises: solid sample dissolution, via an alkaline fusion with sodium carbonate, and acid leaching with dilute hydrochloric acid, and measurements of emission intensities of 337.276 nm. This method has a detection limit of 31 ng/ml and a reproducibility of 0.90% r.s.d.     

Simultaneous determination of metallic elements in precipitates and inclusions extracted from steel by inductively coupled plasma-atomic emission spectrometry

A study was made about the possibility of extracting complex precipitates, containing carbides, nitrides, intermetallic compounds, from low-alloy steels, high-alloy steels and heat-resistant super alloys by single electrolysis operation, followed by the simultaneous determination of all metallic elements in the precipitates by inductively coupled plasma-atomic emission spectrometry (ICP-AES). As a result, it was found that 4–5 metallic elements, such as Nb, Mo and Cr, whose determination had been considered difficult even by wet chemical analysis, can be simultaneously determined in the dissolved state in which Na₂S₂O₇ and tartaric acid (20%) added for the treatment of precipitates are concomitants.ICP-AES simplifies the analytical operation considerably and shortens the analytical time from about 18 h by conventional methods to about 1 h.     

Microwave digestion methods for the determination of trace elements in brain and liver samples by inductively coupled plasma mass spectrometry

Two microwave digestion systems (open-focused and closed-pressurized) were tested for the mineralization of human brain and bovine liver (NIST SRM 1577a) as dissolution steps prior to the determination of 16 trace elements (Bi, Cd, Co, Cs, Cu, Fe, Hg, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) by inductively coupled plasma mass spectrometry (ICP-MS). Digestion parameters (mass of sample, digestion mixture, and power/time steps) were optimized using temperature and pressure sensors. Digestions with the open-focused microwave system require larger volumes of conc. HNO₃ and 30% H₂O₂ than digestions with the closed-pressurized system. Both systems produce correct results for the bovine liver samples. The concentrations obtained for the digests of the open-focused system tend to be less precise than the concentrations from the closed-pressurized digests. Because the open-focused digests must be diluted to 50 mL to bring the acid concentration to 0.7–2.0 mol/L required by the ICP-MS (closed-pressurized digests need to be diluted to only 20 mL), the detection limits for the system with the open-focused digestion are higher than for the system with the closed-pressurized digestor. The open-focused digestor cannot handle more than 150 mg brain tissue, whereas the closed-pressurized system can mineralize 470 mg. The latter method gave better results with brain tissue than the open-focused system. The preparation of brain tissue as reference material for the determination of trace elements in brain samples is described.     

电感耦合等离子体原子发射光谱法测定铈矿中微量的砷、锑

采用过氧化钠熔融试样，用盐酸调节试液酸度，对电感耦合等离子体原子发射光谱（ICP－AES）法同时测定铈矿中微量砷和锑进行了研究，考察了铈基体及共存元素，试液酸度及介质等因素对砷和锑的光谱和非光谱影响。     

Microwave digestion methods for the determination of trace elements in brain and liver samples by inductively coupled plasma mass spectrometry

Two microwave digestion systems (open-focused and closed-pressurized) were tested for the mineralization of human brain and bovine liver (NIST SRM 1577a) as dissolution steps prior to the determination of 16 trace elements (Bi, Cd, Co, Cs, Cu, Fe, Hg, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) by inductively coupled plasma mass spectrometry (ICP-MS). Digestion parameters (mass of sample, digestion mixture, and power/time steps) were optimized using temperature and pressure sensors. Digestions with the open-focused microwave system require larger volumes of conc. HNO(3) and 30% H(2)O(2) than digestions with the closed-pressurized system. Both systems produce correct results for the bovine liver samples. The concentrations obtained for the digests of the open-focused system tend to be less precise than the concentrations from the "closed-pressurized" digests. Because the "open-focused" digests must be diluted to 50 mL to bring the acid concentration to 0.7-2.0 mol/L required by the ICP-MS (closed-pressurized digests need to be diluted to only 20 mL), the detection limits for the system with the open-focused digestion are higher than for the system with the closed-pressurized digestor. The open-focused digestor cannot handle more than 150 mg brain tissue, whereas the closed-pressurized system can mineralize 470 mg. The latter method gave better results with brain tissue than the open-focused system. The preparation of brain tissue as reference material for the determination of trace elements in brain samples is described.     

An indirect method for the determination of chromium species in water samples by sequential inductively coupled plasma-atomic emission spectrometry

Determination of Cr(VI) and Cr(III) in water samples by inductively coupled argon plasma-atomic emission spectrometry (ICP-AES) was performed indirectly employing an on-line system. For this purpose a column with copper shavings was used to reduce Cr(VI) to Cr(III) in acidic media, generating Cu(II) ions in the flow path. This process permitted the evaluation of concentrations in the range of 1–50 mg/l. The protocol allowed a throughput of 100 samples per hour with 10% precision in the concentration     

Evaluation of vapor generation for the determination of nickel by inductively coupled plasma-atomic emission spectrometry

Volatile species of Ni were generated by merging acidified aqueous samples and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the inlet tube of the plasma torch. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for detection. The operating conditions (chemical and physical parameters) and the concentrations of different acids were evaluated for the efficient generation of Ni vapor. The detection limit (3 sigma(blank)) was 1.8 ng mL(-1). The precision (RSD) of the determination was 4.2% at a level of 500 ng mL(-1) and 7.3% for 20 ng mL(-1) (n=10). The efficiency of the generation process was estimated to be 51%. The possible interfering effect of transition metals (Cd, Co, Cu, Cr, Fe, Mn, Zn), hydride forming elements (As, Ge, Pb, Sb, Se, Sn, Te), and Hg on Ni signal was examined. This study has demonstrated that Ni vapor generation is markedly free of interferences.     

Separation and preconcentration of ultra trace amounts of beryllium in water samples using mixed micelle-mediated extraction and determination by inductively coupled plasma-atomic emission spectrometry

In the present study a cloud point extraction process using mixed micelle of the cationic surfactant cetyl-pyridinium chloride (CPC) and non-ionic surfactant Triton X-114 for extraction of beryllium from aqueous solutions is developed. The extraction of analyte from aqueous samples was performed in the presence of 1,8-dihydroxyanthrone as chelating agent in buffer media of pH 9.5. After phase separation, the surfactant-rich phase was diluted with 0.4 mL of a 60:40 methanol-water mixture containing 0.03 mL HNO₃. Then, the enriched analyte in the surfactant-rich phase was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The different variables affecting the complexation and extraction conditions were optimized. Under the optimum conditions (i.e. 1.6 × 10⁻⁴ mol L⁻¹ 1,8-dihydroxyanthrone, 1.2 × 10⁻⁴ mol L⁻¹ CPC, 0.15% (v/v) Triton X-114, 50 °C equilibrium temperature) the calibration graph was linear in the range of 0.006-80 ng mL⁻¹ with detection limit of 0.001 ng mL⁻¹ and the precision (R.S.D.%) for five replicate determinations at 18 ng mL⁻¹ of Be(II) was better than 2.9%. In this manner the preconcentration and enrichment factors were 16.7 and 24.8, respectively. Under the presence of foreign ions no significant interference was observed. Finally, the proposed method was successfully utilized for the determination of this cation in water samples.     

On-line preconcentration and simultaneous determination of heavy metal ions by inductively coupled plasma-atomic emission spectrometry

A flow injection analysis system for on-line preconcentration and simultaneous determination of Bi³⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺ and Zn²⁺ in aqueous samples by inductively coupled plasma (ICP)-atomic emission spectrometry with a charge coupled detector is described. The preconcentration of analytes is accomplished by retention of their chelates with sodium diethyldithiocarbamate in aqueous solution on a solid phase containing octadecyl silica in a minicolumn. Methanol, as eluent, is introduced into the conventional nebulizer of the ICP instrument. The effects of different parameters, including preconcentration flow rate (equal to sample flow rate (SR)), eluent flow rate (ER), weight of solid phase (W) and eluent loop volume (EV), were optimized by the super-modified simplex method. The optimum conditions were evaluated to be SR 7.2 ml min⁻¹, ER 3.5 ml min⁻¹, W of 100 mg and EV of 0.8 ml. An enrichment factor of 312.5 for each analyte was obtained. The detection limits of the proposed method for Bi³⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺ and Zn²⁺ were evaluated as 1.3, 1.0, 0.8, 0.3, 14.7, 0.5, 5.5 and 0.1 ng l⁻¹, respectively. The effect of several metal ions on percent recovery was also studied. The method was applied to the recovery of these heavy metals from real matrices and to the simultaneous determination of these cations in different water samples.     

Direct inductively coupled plasma-atomic emission spectrometry analysis of trace elements in muscle tissues of hairtail using electrothermal vaporization with slurry sampling

A procedure for direct determination of trace elements in muscle tissue of hairtail was developed using inductively coupled plasma-atomic emission spectrometry and electrothermal vaporization with slurry sampling. Due to use of polytetrafluoroethylene as the chemical modifier, the vaporization behaviors of analytes from the slurry and the aqueous standard solutions were very similar. In this case, the aqueous standards could be used for the calibration of slurry samples. The main factors influencing this method were studied systematically. The detection limits for Cr, Ni, Zn, Cd, and Pb were 3.1, 10.5, 176, 6.9, and 83 ng/mL, respectively, and the relative standard deviations were less than 10%. The proposed method was applied to the determination of trace Cr, Ni, Zn, Cd, and Pb in hairtail samples with satisfactory accuracy and precision. A certified reference material of mussel (GBW 08571) was analyzed, and good agreement was obtained between the results from the proposed method and certificate values.     

Sequential-injection on-line preconcentration using chitosan resin functionalized with 2-amino-5-hydroxy benzoic acid for the determination of trace elements in environmental water samples by inductively coupled plasma-atomic emission spectrometry

A new chelating resin using chitosan as a base material was synthesized. Functional moiety of 2-amino-5-hydroxy benzoic acid (AHBA) was chemically bonded to the amino group of cross-linked chitosan (CCTS) through the arm of chloromethyloxirane (CCTS-AHBA resin). Several elements, such as Ag, Be, Cd, Co, Cu, Ni, Pb, U, V, and rare earth elements (REEs), could be adsorbed on the resin. To use the resin for on-line pretreatment, the resin was packed in a mini-column and installed into a sequential-injection/automated pretreatment system (Auto-Pret System) coupled with inductively coupled plasma-atomic emission spectrometry (ICP-AES). The sequential-injection/automated pretreatment system was a laboratory-assembled, and the program was written using Visual Basic software. This system can provide easy operation procedures, less reagent consumption, as well as less waste production.

Experimental variables considered as effective factors in the improvement sensitivity, such as an eluent concentration, a sample and an eluent flow rate, pH of samples, and air-sandwiched eluent were carefully optimized. The proposed system provides excellent on-line collection efficiency, as well as high concentration factors of analytes in water samples, which results in highly sensitive detection of ultra-trace and trace analysis. Under the optimal conditions, the detection limits of 24 elements examined are in the range from ppt to sub-ppb levels. The proposed method was validated by using the standard reference material of a river water, SLRS-4, and the applicability was further demonstrated to the on-line collection/concentration of trace elements, such as Ag, Be, Cd, Co, Cu, Ni, Pb, U, V, and REEs in water samples.     

Determination of major and minor elements in silicates by inductively coupled plasma emission spectrometry

A simple rapid method for the determination of major and minor elements in silicates is reported. Powdered sample (50 mg) is treated with hydrochloric and hydrofluoric acids in a small sealed Teflon vessel. After addition of boric acid, silicon, aluminium, iron, titanium, manganese, calcium, magnesium, sodium, and potassium are determined by inductively coupled plasma emission spectrometry. The method is satisfactory for a variety of standard silicate materials.