Simultaneous Determination Of Trace Metals Research Articles

Validation of microwave-assisted digestion and Inductive coupled plasma -mass spectrometer for the determination of trace metals in the soil around Darvill sludgeland and their environmental complications

ABSTRACT This study presents the optimization, validation, and application of microwave-assisted digestion and inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous determination of trace metals (B, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, Zn, and As) in soils from sludgeland. This analytical method was validated according to the requirements of ISO standards for new methods, which include parameters such as linearity, sensitivity and range, accuracy, precision, selectivity, the limit of detection (LOD), the limit of quantification (LOQ), and recoveries. The method demonstrated good linearity with a correlation coefficient greater than 0.999 for all 12 metals of interest. The limit of detection (LOD) was found to be between 0.001 and 0.006 µg/L and the Limit of Quantification (LOQ) was between 5 and 200 µg/L. The method was then applied to soil samples from 28 sites where sludge is disposed to assess the presence of trace metals and their concentrations were compared with background concentrations of metals in South Africa. The Cr with the value ranging from 83.5 mg/kg to 480 mg/kg exceeded the limits in all sites while Zn, Co, Ni, As exceeded in some sites. Geo accumulation was then used to categorize the contamination level of soil by trace metals and observed to be strongly contaminated by Zn with values between 1.2 and 3.5 while moderately contaminated by Pb, Ni, Cu, and As with values between 1.3 and 2.7 which poses their environmental risk.

Analysis of Cu, Co, V and Zn in coastal waters of the East China Sea by inductively coupled plasma mass spectrometry (ICP-MS)

In this study, a simple method for the simultaneous determination of trace metals (Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry (ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L−1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.

Calconcarboxylic acid dynamically modified nanometer-sized zirconia for on-line flow injection-inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples

A novel adsorbent was synthesized by grafting calconcarboxylic acid (CAA) dynamically to nanometer-sized zirconia (ZrO2) and was characterized with a transmission electron microscope, nitrogen adsorption instrument and infrared spectroscopy. By using CAA modified nanometer-sized ZrO2 as micro-column packing material, a new method of flow injection (FI) on-line preconcentration coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) was developed for simultaneous determination of trace metals (Cd, Co, Cu, Ni and Pb) in environmental water samples. The experimental parameters including pH, sample flow rate and volume, elution volume and flow rate and coexisting ions on the extraction of the target analytes were investigated, and the optimal experimental conditions were established. Under the optimized operating conditions, the limits of detection (LODs) of this method for Cd, Co, Cu, Ni and Pb were 0.16, 0.04, 0.28, 0.22, and 0.95 ng mL−1, with the relative standard deviations (RSDs) of 2.2, 3.0, 4.5, 4.1 and 7.7% (n = 7, c = 10 ng mL−1), respectively. An enrichment factor of 10 and sampling frequency of 12 h−1 were obtained by using a loading time of 200 s and elution time of 30 s. The proposed method was validated by analysis of the target metals in Certified Reference Materials of GSBZ50009-88 environmental water and real-world natural water samples.

Using arc-excitation atomic emission spectrometry in studying the microelement composition of bottom sediments

A procedure is developed for the simultaneous determination of trace metals in river, sea, and lake bottom sediments by atomic emission spectrometry. A present-day scenario using a new system of spectrum record and universal buffer mixtures ensures sufficiently reliable results of analysis of samples of complex composition.

Simultaneous determination of mercury, lead and cadmium ions in water using near-infrared spectroscopy with preconcentration by thiol-functionalized magnesium phyllosilicate clay

Analysis of metal ions in environment is of great importance for evaluating the risk of heavy metal to public health and ecological safety. A method for simultaneous determination of metal ions in water samples was developed by using adsorption preconcentration and near-infrared diffuse reflectance spectroscopy (NIRDRS). A high capacity adsorbent of thiol-functionalized magnesium phyllosilicate, named Mg-MTMS, was prepared by co-condensation for preconcentration of Hg 2+, Pb 2+ and Cd 2+ in aqueous solutions. After adsorbing the analytes onto the adsorbent, NIRDRS was measured and PLS models were established for fast and simultaneous quantitative prediction. Because the interaction of the ions with the functional group of the adsorbent can be reflected in the spectra, the models built with the samples prepared by river water were proven to be efficient enough for precise prediction. The determination coefficients ( R 2) of the validation samples for the three ions were found as high as 0.9197, 0.9599 and 0.9861, respectively. Furthermore, because the high adsorption efficiency of Mg-MTMS, the detected concentrations are as low as milligrams per liter for the three ions, and the concentration can be further reduced. Therefore, the feasibility of quantitative analysis metal ions in river water by NIRDRS is proven and this may provide a new way for fast simultaneous determination of trace metals in environmental waters.

Membrane solid phase microextraction with alumina hollow fiber on line coupled with ICP-OES for the determination of trace copper, manganese and nickel in environmental water samples

A novel alumina hollow fiber was synthesized by sol–gel template method and was characterized by scanning electron microscopy, N2 adsorption technique and X-ray diffraction. With the use of prepared alumina hollow fiber as extraction membrane, a new method of flow injection (FI)-membrane solid phase microextraction (MSPME) on-line coupled to inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for simultaneous determination of trace metals (Cu, Mn and Ni) in environmental water samples. The adsorption capacities of the alumina hollow fiber for Cu, Mn and Ni were found to be 6.6, 8.7 and 13.3mgg−1, respectively. With a preconcentration factor of 10, the limits of detection (LODs) for Cu, Mn and Ni were found to be 0.88, 0.61 and 0.38ngmL−1, respectively, and the relative standard deviations (RSDs) were ranging from 6.2 to 7.9% (n=7, c=10ngmL−1). To validate the accuracy, the proposed method was applied to the analysis of certified reference material GSBZ50009-88 environmental water and the determined values are in good agreement with the certified values. The developed method was also employed for the analysis of Yangtze River water and East Lake water, and the recoveries for the spiked samples were in the range of 87.4–110.2%.

Liquid Electrode Plasma Atomic Emission Spectrometry Combined with Multi-Element Concentration Using Liquid Organic Ion Associate Extraction for Simultaneous Determination of Trace Metals in Water

液体電極プラズマ発光分析法（LEP-AES）は小型化可能な元素分析法であり，ガス供給や大型電源が不要なため，現場分析に適する．本研究では，LEP-AESと微小体積に短時間で高濃縮できる有機イオン会合体抽出法による濃縮を組み合わせ，微量金属（Cu，Mn，Pd，Zn，Cd，Pb）の一括濃縮/同時定量法を開発した．試料水40 mLにキレート試薬を加え，重金属を錯体とし，水相から生成させた有機イオン会合体中に抽出した．この会合体の体積はμLレベルである．これをメタノールに溶解し，硝酸溶液を加え400 μLとした．40 μLを分取してLEP-AESで測定した．濃縮倍率は100倍である．以上の濃縮/定量法より，短時間で高感度な現場元素分析が可能となり，検出限界は数μg L－1～数百μg L－1となった．いくつかの元素は濃縮倍率以上に感度が上昇した．また，廃液の認証標準物質に適用したところ，測定値は認証値の許容範囲内であった．

Micro-column preconcentration/separation using thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO 2 as packing materials on-line coupled to inductively coupled plasma optical emission spectrometry for the determination of trace heavy metals in environmental water samples

A novel adsorbent of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO 2 was prepared and was used as a packing material for flow injection (FI) micro-column (20 mm × 4.0 mm i.d.) separation/preconcentration on-line coupled to inductively coupled plasma optical emission spectrometry (ICP-OES) simultaneous determination of trace metals (V, Cu, Pb, Cr) in environmental water samples. The experimental conditions for modified mesoporous TiO 2 packed micro-column separation/preconcentration of the target metals were optimized and the interference of commonly coexisting ions was examined. The adsorption capacities of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO 2 for V, Cu, Pb and Cr were found to be 14.0, 11.7, 17.7 and 14.5 mg g − 1 , respectively. The detection limits of the method were 0.09, 0.23, 0.50 and 0.15 µg L − 1 for V, Cu, Pb and Cr, respectively, with a preconcentration factor of 20. The precision of this method were 1.7% (V), 3.9% (Cu), 4.6% (Pb) and 2.9% (Cr) ( n = 7, C = 5 µg L − 1 ), respectively. The developed method was applied to the determination of trace heavy metals in real samples and the recoveries for spiked samples were found to be in the range of 88.7–107.1%. For validation, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values.

Kinetic and equilibrium studies for the adsorption process of cadmium(II) and copper(II) onto Pseudomonas aeruginosa using square wave anodic stripping voltammetry method

A novel method for the simultaneous determination of cadmium(II) and copper(II) during the adsorption process onto Pseudomonas aeruginosa was developed. The concentration of the free metal ions was successfully detected by square wave anodic stripping voltammetry (SWASV) on the mercaptoethane sulfonate (MES) modified gold electrode, while the P. aeruginosa was efficiently avoided approaching to the electrode surface by the MES monolayer. And the anodic stripping peaks of Cd 2+ and Cu 2+ appear at −0.13 and 0.34 V respectively, at the concentration range of 5–50 μM, the peak currents of SWASV present linear relationships with the concentrations of cadmium and copper respectively. As the determination of Cd 2+ and Cu 2+ was in real time and without pretreatment, the kinetic characteristics of the adsorption process were studied and all the corresponding regression parameters were obtained by fitting the electrochemical experimental data to the pseudo-second-order kinetic model. Moreover, Langmuir and Freundlich models well described the biosorption isotherms. And there were some differences in the amount of metal ion adsorbed at equilibrium ( q e ) and other kinetics parameters when the two ions coexisted were compared with the unaccompanied condition, which were also discussed in this paper. The proposed electrode system provides excellent platform for the simultaneous determination of trace metals in complex biosorption process.

Development of an isotope dilution laser ablation ICP-MS method for multi-element determination in crude and fuel oil samples

An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method with direct introduction of the isotope-diluted sample into the plasma by laser ablation was developed for accurate, sensitive, fast, and simultaneous determination of trace metals in different oil samples. Metallo-organic solutions of isotope spikes (50V, 53Cr, 65Cu, 57Fe, 62Ni, 68Zn, 113Cd, 117Sn, and 206Pb) were prepared from corresponding aqueous stock solutions by using liquid–liquid extraction of complexed metal ions in isobutyl methyl ketone. The isotope-diluted sample was absorbed by a cellulose material, which was fixed in a special PTFE holder for ablation, using a laser system with high ablation rates. Under these conditions, no time-dependent spike/analyte fractionation was observed for the metallo-organic spike/oil mixtures and the measured isotope ratios of the isotope-diluted samples remained constant over the whole ablation time, which is a necessary precondition for accurate results with the isotope dilution technique. The accuracy of LA-ICP-IDMS determinations was demonstrated by analyzing the fuel oil reference material BCR 1634c, certified for vanadium and nickel, a commercially available oil based standard (SCP-21) for nine metals, and by comparing LA-ICP-IDMS results with those obtained by ICP-IDMS using microwave-assisted sample digestion. Detection limits in the range of 0.02 µg g−1 (V) to 0.2 µg g−1 (Fe) were obtained for LA-ICP-IDMS by total analysis times per sample of only 10 min. Three crude oil samples of different origin with vanadium, nickel, and iron concentrations in the range of 2–60 µg g−1 were also analyzed, indicating iron heterogeneities by the relatively high standard deviation.

Voltammetric methods for the simultaneous determination of trace metals in foods, plant tissues and soils

AbstractAn analytical procedure for the sequential determination of copper(II), chromium(VI), thallium(I), lead(II), tin(II), antimony(III) and zinc(II) by anodic stripping voltammetry (ASV) in three interdependent matrices involved in foods and food chain as meals, cereal plants and soils is described. The digestion of each matrix was carried out using a mixture of concentrated acids: HClHNO3H2SO4 for meals and cereal plants, and HClHNO3 for soils. Dibasic ammonium citrate (0.1 mol L−1; at either pH 6.2 or 8.3) was used as the supporting electrolyte. The voltammetric measurements were carried out using, as working electrode, a stationary hanging mercury drop electrode (HMDE) and a platinum electrode and an Ag|AgCl|KClsat. electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by the analyses of the standard reference materials: Wholemeal BCR‐CRM 189, Wheat Flour NIST‐SRM 1567a, Tomato Leaves NIST‐SRM 1573a and Montana Soil Moderately Elevated Traces NIST‐SRM 2711. For all the elements in the certified matrix, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3–5%. The accuracy, expressed as relative error (e) was of the order of 3–7%, while the detection limits were in the range 0.011–0103 µg g−1. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial meal samples and cereal plants and soil samples taken from sites used for agriculture. A critical comparison with spectroscopic measurements is also discussed. Copyright © 2006 Society of Chemical Industry

Simultaneous on-line preconcentration and determination of trace metals in environmental samples using a modified nanometer-sized alumina packed micro-column by flow injection combined with ICP-OES

A novel organic reagent 3-(8-quinolinylazo)-4-hydroxybenzoic acid (QAHBA) was synthesized for chemically modified nanometer-sized alumina, and it was characterized with infrared spectrum and 1H NMR spectra. By using modified nanometer-sized alumina as micro-column packing material, a new method of flow injection (FI) on-line preconcentration coupled to ICP-OES was developed for simultaneous determination of trace metals (Ag, Pd, Au, Ga, In and Nb) in geological and environmental samples. The effects of pH, sample flow rate, sample volume, elution and interfering ions on the recovery of the analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the modified nanometer-sized alumina for Ag, Pd, Au, Ga, In and Nb were found to be 5.1, 7.6, 17.7, 15.6, 8.1 and 12.3 mg g −1, respectively. With 4 min preconcentration time and 24 s elution time, the enrichment factor was 10 and the sample frequency was 10 h −1. The detection limits of this method for Ag, Pd, Au, Ga, In and Nb were 0.12, 0.44, 0.27, 0.19, 0.54 and 0.18 μg l −1, respectively, while the R.S.D.s were 1.6, 2.3, 4.5, 1.6, 1.9 and 1.7% ( n = 7, c = 50 ng ml −1), respectively. The proposed method has been applied to the determination of these trace metals in geological-certified reference materials and natural water samples with satisfactory results.

Simultaneous on-line preconcentration and determination of trace metals in environmental samples by flow injection combined with inductively coupled plasma mass spectrometry using a nanometer-sized alumina packed micro-column

A flow injection (FI) on-line preconcentration procedure by using a nanometer-sized alumina packed micro-column coupled to inductively coupled plasma mass spectrometry (ICP-MS) was described for simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in the environmental samples. The effects of pH value, sample flow rate, preconcentration time, and interfering ions on the preconcentration of analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the nanometer-sized alumina for V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were found to be 11.7, 13.6, 15.7, 9.5, 12.2, 13.3, 17.1, 17.7 and 17.5 mg g −1, respectively. With 60 s preconcentration time and 60 s elution time, an enrichment factor of 5 and the sampling frequency of 15 h −1 were obtained. The proposed method has been applied to the determination of trace metals in environmental certified reference materials and natural water samples with satisfactory results.

Overlapping voltammetric peaks?an analytical procedure for simultaneous determination of trace metals. Application to food and environmental matrices

Voltammetric methods are very suitable, versatile and rapid techniques for simultaneous determination of metals in complex matrices. The present work, determination of Cu(II), Sn(II), Sb(III), Tl(I), and Pb(II) by square-wave anodic-stripping voltammetry and Cr(VI) by square-wave adsorptive-stripping voltammetry, is an interesting example of the possibility of simultaneous determination of each single element in food and environmental samples, even in the presence of reciprocal interference. Dibasic ammonium citrate, pH 6.3 or 8.2, was employed as supporting electrolyte. The voltammetric measurements were carried out using a stationary hanging mercury drop electrode as working electrode and a platinum electrode and an Ag|AgCl|KCl(sat) electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by analysis of standard reference materials--wholemeal BCR-CRM 189, wheat flour NIST-SRM 1567a, rice flour NIST-SRM 1568a, estuarine sediment BCR-CRM 277, river sediment BCR-CRM 320, and Montana soil with moderately elevated traces NIST-SRM 2711. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were generally below 6% whereas limits of detection for each element were below 0.069 microg g(-1). In the presence of reciprocal interference the standard addition method considerably improved the resolution of the voltammetric technique, even for very high element concentration ratios. After being set up on the standard reference materials the analytical procedure was transferred and applied to commercial samples of meal and soil samples taken from sites devoted to agricultural practice. A critical comparison with graphite furnace atomic-absorption spectroscopy is also discussed.

Electrothermal Vaporization — Inductively Coupled Plasma–Mass Spectrometry (ETV-ICP-MS): A Valuable Tool for Direct Multielement Determination in Solid Samples

Solid Sampling-Electrothermal Vaporization-Inductively Coupled Plasma-Mass Spectrometry (SS-ETV-ICP-MS) is an attractive technique for the direct simultaneous determination of trace metals in solid samples. During recent years, some important developments dealing with ETV-ICP coupling and with analyte transport efficiencies have been reported, and so SS-ETV-ICP-MS has received a renewed interest by the atomic spectroscopy community. Thus, the present review highlights the inherent capabilities of SS-ETV-ICP-MS for the simultaneous determination of trace metals. In addition, technical aspects of ETV-ICP coupling as well as more recent applications are reported. It is concluded that this technique is a powerful tool for sorting out some of the current analytical challenges, and future advances are to be expected in order to widen the field of application.

Simultaneous determination of trace metals by solid phase absorptiometry: application to flow analysis of some rare earths

Solid phase absorptiometry was applied to the simultaneous flow analysis of trace metals in combination with a micro black flow-through cell packed with ion exchanger beads and a multi-channel photodetector connected with optical fibers. A 4.0 cm3 sample solution containing five rare earth metal ions (Dy, Ho, Tm, Er and Nd) was introduced into a flow system and these metal ions were concentrated on a cation exchanger (Muromac 50W-X4) in a flow-through cell. The absorbance increases originating from the f-f or d-f transition bands of these metal ions were directly and continuously measured at 910 nm for Dy, at 530 nm for Ho, at 683 nm for Tm, 522 nm for Er and at 790 nm for Nd, respectively. A multi-variable analysis method was combined with the flow analysis because the absorption spectra of the five rare earth metal ions partly overlapped one another. Although no coloring reagents were used, the proposed method was about ¶200 times more sensitive than the corresponding solution method. The reproducibility of this method was less than ± 5%. The detection limits were 0.03, 0.40, 0.30, 0.35 and 0.23 mg dm–3 for Dy, Ho, Tm, Er and Nd, respectively. Five rare earth metal ions could be precisely determined in practical samples such as yttrium concentrate.

Voltammetric Trace Analysis of Uranium and Other Metals in Meta Rhyolite Rock Samples

Direct current polarography (DCP), differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASV) have been successfully used for the simultaneous determination of trace metals in meta rhyolite rock samples. The polarograms/voltammograms of sample solutions were recorded in 0.1 M KCl, 0.1 M ammonium tartrate and 0.1 M KSCN supporting electrolyte separately. The results indicated the presence of Zn2+, Fe3+, Mn2+, Cu2+ and UO22+ metal ions. Uranium gave a well-defined polarographic wave/peak with E1/2/EP -0.26/-0.26 V vs. SCE in 0.1 M KSCN. The method of standard addition was for the quantitative analysis of trace metals, which revealed the following results: Zn2+ (22.22), Fe3+ (147.10), Mn2+ (5.50), Cu2+ (28.58) and UO22+ (0.059) mg g-1 of the sample. The observed voltammetric results were compared with those obtained using AAS. Statistical treatment of the observed voltammetric data revealed high accuracy and good precision of the determination.

Studies of the Simultaneous Determination of Trace Metals by High-Performance Liquid Chromatography/DNA Ligands with New Functions for Analyzing DNA

Studies of the Simultaneous Determination of Trace Metals by High-Performance Liquid Chromatography/DNA Ligands with New Functions for Analyzing DNA

Simultaneous determination of trace metals in human hair by dynamic ion-exchange chromatography

The simultaneous determination of six metal ions (Cu 2+, Zn 2+, Ni 2+, Mn 2+, Co 2+, Pb 2+) by using dynamic ion-exchange chromatography is proposed. The method was applied to the analysis of human hair after HNO 3HClO 4 digestion, with detection limits of ca. 1 μg g −1 for all the metals examined, using Co as an internal standard. The quantitative data were confirmed by analysing the same hair samples by atomic absorption spectrometry and x-ray fluorescence spectrometry.

Chemically modified electrode for the simultaneous determination of trace metals and speciation analysis

A modified carbon paste electrode was used for the simultaneous determination of Zn, Cd, Pb, Cu and Hg. Trace metal preconcentration was effected by selective retention on Amberlite IRC 718 chelating resin as an electrode modifier, with subsequent measurement by differential-pulse voltammetry. Peak potentials for he reoxidation of these metals occur at −1.05, −0.80, −0.48, −0.24 and 0.06 V, respectively, allowing determinations at the μg 1−1 level. Several metal ratios were studied in order to determine the influence of each metal on the determination of the others. The influence of other substances was also studied to determine the potential of the method for speciation analysis studies.