Voltammetric procedure for trace metal analysis in polluted natural waters using homemade bare gold-disk microelectrodes

Voltammetric procedures for trace metals analysis in polluted natural waters using homemade bare gold-disk microelectrodes of 25- and 125-μm diameters have been determined. In filtered seawater samples, square wave anodic stripping voltammetry (SWASV) with a frequency of 25 Hz is applied for analysis, whereas in unfiltered contaminated river samples, differential pulse anodic stripping voltammetry (DPASV) gave more reliable results. The peak potentials of the determined trace metals are shifted to more positive values compared to mercury drop or mercury-coated electrodes, with Zn always displaying 2 peaks, and Pb and Cd inversing their positions. For a deposition step of 120 s at ?1.1 V, without stirring, the 25-μm gold-disk microelectrode has a linear response for Cd, Cu, Mn, Pb and Zn from 0.2 μg L^?1 (1 μg L^?1 for Mn) to 20 μg L^?1 (30 μg L^?1 for Zn, Pb and 80 μg L^?1 for Mn). Under the same analytical conditions, the 125-μm gold-disk microelectrode shows linear behaviour for Cd, Cu, Pb and Zn from 1 μg L^?1 (5 μg L^?1 for Cd) to 100 μg L^?1 (200 μg L^?1 for Pb). The sensitivity of the 25-μm electrode varied for different analytes from 0.23 (±0.5%, Mn) to 4.83 (±0.9%, Pb) nA L μmol^?1, and sensitivity of the 125-μm electrode varied from 1.48 (±0.7%, Zn) to 58.53 (±1.1%, Pb  nA L μmol^?1. These microelectrodes have been validated for natural sample analysis by use in an on-site system to monitor Cu, Pb and Zn labile concentrations in the Deûle River (France), polluted by industrial activities. First results obtained on sediment core issued from the same location have shown the ability of this type of microelectrode for in situ measurements of Pb and Mn concentrations in anoxic sediments.      

Determination of Heavy Metal Content in Wild-Edible Mushroom from Jordan

The heavy metal content was investigated for six mushroom species native to Jordan. Metal (Cu, Pb, Cd, Fe, Zn, Mn, Ni, and Co) content in soil substrate and their relation to metal concentrations in mushroom and underlying soil were determined by flame and graphite furnace atomic absorption spectrometry. Mushroom species and soil were collected from different places in Jordan. The highest Cu level was 51.84 µg g^?1 for the species Lepista nuda; whereas, the lowest Cu level was found to be 18.51 µg g^?1 in Calvatia utriformis. Among the wild mushrooms, the highest Pb level was found as 4.81 µg g^?1 in Bovista plumbea, whereas the lowest Pb concentration was 2.01 µg g^?1 in Calvatia utriformis. The highest Cd level was determined as 1.9 µg g^?1 for Lepista nuda, whereas the lowest Cd level was 0.58 µg g^?1 for the species of Polyporus frondosus. The highest Zn level was 58.77 µg g^?1 for the species of Lepista nuda and the lowest Zn concentration was found 35.98 µg g^?1 in Calvatia utriformis. The highest Fe level was found as 317 µg g^?1 in Lepista nuda, whereas the lowest Fe concentration was 211.7 µg g^?1 in Calvatia utriformis. The highest Mn content was 36.55 µg g^?1 for Russula delica, whereas the lowest Mn level was 24.5 µg g^?1 for the species Bovista plumbea. The highest Ni content was found as 12.65 µg g^?1 for Russula delica, whereas the lowest Ni level was 0.17 µg g^?1 for Bovista plumbea. The highest Co content in the tested mushrooms was found as 3.5 µg g^?1 for the species of Agaricus bisporus, whereas the lowest Co level was 0.85 µg g^?1 for Polyporus frondosus. The results indicated that, in general, heavy metal contents in all mushroom species were lower than the underlying soil substrates except for some mushroom species.     

Determination of reference interval values for inorganic elements in whole blood samples of humans and laboratory animals by X-ray fluorescence spectrometry

Inorganic elements are responsible for essential bodily functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma and urine is used as a monitor for a part or the whole organism; their values, then, are compared with reference interval values. In this study, the energy dispersive X-ray fluorescence spectrometry (EDXRF), applying the Fundamental Parameters method, for the determination of inorganic elements in whole blood samples from humans and laboratory animals, was used. Peripheral blood samples were collected and, before coagulation, 100 μL of sample were deposited onto Whatman No. 41 filter paper and dried, using infrared spotlight. The reference interval values for healthy Brazilian population of Na were found to be 1,788–1,826 μg g^?1, of Mg 63–75 μg g^?1, of P 602–676 μg g^?1, of S 1,519–1,718 μg g^?1, of Cl 2,743–2,867 μg g^?1, of K 1,508–1,630 μg g^?1, of Ca 214–228 μg g^?1, of Fe 170–184 μg g^?1, of Cu 4–6 μg g^?1 and of Zn 1–3 μg g^?1. The reference interval values for golden hamster (Mesocricetus auratus) of Na were found to be 1,714–1,819 μg g^?1, Mg 51–79 μg g^?1, P 970–1,080 μg g^?1, S 1,231–1,739 μg g^?1, Cl 2,775–2,865 μg g^?1, of K 1,968–2,248 μg g^?1, of Ca 209–257 μg g^?1, of Fe 145–267 μg g^?1, of Cu 4–6 μg g^?1 and of Zn 3–5 μg g^?1. A comparative study between EDXRF and instrumental neutron activation analysis data was carried out and the results for both techniques are statistically equal (α = 0.05). The results contribute for the establishment of reference interval values for Na, Mg, P, S, Cl, K, Ca, Cu and Zn in the healthy Brazilian population and the referred laboratory animal species.     

Determination of Cd and Pb in Honey by SF‐ICP‐MS: Validation Figures and Uncertainty of Results

Abstract

A method based on microwave‐assisted acid digestion of honey and quantification of Cd and Pb by Sector Field Inductively Coupled Plasma Mass Spectrometry was in‐house validated and the combined uncertainty was estimated according to the Eurachem/Citac Guide. Limits of detection and quantification were 0.07 and 0.20 ng g^?1 for Cd, and 0.70 and 2.10 ng g^?1 for Pb; recovery was 103.9% for Cd and 98.5% for Pb; repeatability was 10.7% for Cd and 18.5% for Pb; within‐laboratory reproducibility was 15.2% for Cd and 21.4% for Pb. Relative combined uncertainty in honey was 15% for Cd and 22% for Pb, with the main contribution coming from the within‐laboratory reproducibility. The method showed robustness when subjected to different working conditions and when applied to various Italian honeys. Cadmium content ranged 0.2–1.37 ng g^?1 and Pb 4.6–30.5 ng g^?1 in flower honeys, while the highest concentrations were presented by honeydew honeys.     

Chemical composition of marine sediments in the Pacific Ocean from Sinaloa to Jalisco, Mexico

Marine sediments from Mexico’s West coast in the Pacific Ocean from Sinaloa to Jalisco were analyzed by energy-dispersive X-ray fluorescence technique. Ten sediment samples were collected in May, 2010 between 55.5 and 1264 m water depth with a Reinneck type box nucleate sampler. Sediments were dried and fractioned by granulometry. Their physical and chemical properties were determined in laboratory by standard methods, pH, and conductivity. Concentration and distribution of K, Ca, Ti Mn, Fe, Cu, Zn, Ga, Pb, Br and Sr were analyzed. In order to determine the status of the elements, enrichment factors were calculated. Total, organic carbon and CaCO₃ were also determined. Scanning electron microscopy and X-ray diffraction show predominant groups of compounds. As quality-control method, Certified Reference Material was both processed and analyzed at even conditions. Enrichment factors for K, Ca, Ti, Mn Fe, Cu, Zn, Ga, Ni, and Sr show they are conservative elements having concentrations in the range of unpolluted sites giving a base data line for the sampling zone In spite of moderately enrichment factors <100 μm size and bulk fractions, first Pb concentration fraction was similar to those found in not influenced by anthropogenic activities sites nearby Mazatlan Harbor. Bulk fraction concentration (52–133 μg g^?1) and enrichment factor show the influence of anthropogenic sources with values between lowest effect level and a third part of 250 μg g^?1value, which is considered to have severe effect levels for aquatic life.     

A biomonitoring study: <Superscript>210</Superscript>Po and heavy metals in mussels

In various samples of Mytilus galloprovincialis, ²¹⁰Po was determined by alpha-spectrometry while Mn, Fe, Ni, Cu, Zn, Cd, Sn, Hg and Pb by energy dispersive, polarised X-ray fluorescence spectrometry (EDPXRF). The mussels of different sizes were taken from 7 sites in the central Adriatic Sea along the Marche coastal region during the four seasons of the year. ²¹⁰Po activity concentration ranged between 57 and 343 Bq·kg⁻¹ dry weight. The concentration ranges of heavy metals (μg·g⁻¹ dry weight) were as follows: Mn: 72.9–83.1; Fe: 45.1–754; Ni: 1.3–7.6; Cu: 17.9–156; Zn: 60.9–189; Cd: 0.6–1.0; Sn: 0.6–3.9; Hg always <0.5; Pb: 2.0–9.0. The data obtained depend upon the site and the period of the sampling and they are also compared with those obtained by other authors for the same organism in the Mediterranean and other Italian seas.     

Development of a simple and fast ultrasound-assisted extraction method for trace element determination in tobacco samples using ICP-MS

The current study describes a simple and fast method for the determination of Ba, Cd, Co, Cr, Cu, Mn, Ni and Pb in tobacco samples. Commercial cigarettes obtained from local market stores were analysed by inductively coupled plasma mass spectrometry (ICP-MS) after ultrasound-assisted extraction in acidic medium, and the results were compared to those obtained following microwave-assisted digestion of the samples. The sonication time was evaluated from 0 to 60 min, and a 30 min extraction time was selected. The concentration of HNO₃ was also optimised at 0.7 mol L^?1. In order to verify the accuracy of the proposed method, a certified reference material was submitted to the same extraction protocol adopted for the samples, and good agreement with the certified values was obtained at a 95% confidence level, except for Co. The extraction of Pb was also semi-quantitative. A total of four tobacco samples were analysed, with concentrations ranging from 0.4 for Cr to 214.6 µg g^?1 for Mn. The proposed method was demonstrated to be fast, sensitive, precise and accurate for the determination of Ba, Cd, Cr, Cu, Mn an Ni and for the semi-quantitative analysis of Co and Pb in tobacco samples.     

First Systematic Voltammetric Measurements of Cd,Pb, and Cu in Hydrofluoric Acid-Dissolved Siliceous Spicules of Marine Sponges: Application to Antarctic Specimens

Ultrasensitive Square Wave Anodic Stripping Voltammetry is used for the first time for the systematic determination of Cd, Pb, and Cu in siliceous spicules of marine sponges; the procedure is performed directly in hydrofluoric acid solution, according to a procedure previously established in our laboratory, with the aim of demonstrating the feasibility of such measurements and to improve knowledge of heavy metal distribution in Porifera. The following Demospongiae species are considered: Sphaerotylus antarcticus, Haliclona sp., Kirkpatrickia coulmani, and Inflatella belli from the Ross Sea, Antarctica, and Petrosia ficiformis from the Mediterranean Sea, Italy. The method shows a good accuracy; the analytical variability is approximately ±10% for all the metals studied and for all the measurements performed, showing a good repeatability of the method in consideration of low metal concentrations (order of tenths of µg g^?1 dry weight, i.e., of hundreds of ng L^?1 in the HF solution). In particular, the concentrations of heavy metals in the body of the sponge vary in the range 0.038–0.93 µg g^?1 dry weight (d.w.) for Cd, 0.024–0.52 µg g^?1 d.w. for Pb, and 0.32–1.3 µg g^?1 d.w. for Cu. Similar ranges of concentration were recorded in the oscula of S. antarcticus and I. belli. Heavy metal concentration in the spicules can vary within and between specimens and, in particular, siliceous spicules of Antarctic sponges show higher concentrations of Cd and Pb and lower concentrations of Cu than those from the Mediterranean.     

Analysis of bioaccessible concentration of trace elements in plant based edible materials by INAA and ICPMS methods

The total metal concentration and bioaccessible concentration of Cr, Mn, Fe, Cu, Zn, Se in Momordica charantia, Asparagus racemosus, Terminalia arjuna and Syzyzium cumini were measured by instrumental neutron activation analysis and by inductively coupled plasma mass spectrometry analysis (ICP-MS). The bioaccessible concentrations were determined in the gastrointestinal digest obtained after treating dried powdered samples sequentially in gastric and intestinal fluid of porcine origin at physiological conditions. The bioaccessible concentration of Fe was in the range of 58–67 mg kg^?1, Mn was 10.2–14.6 mg kg^?1, Cu was 3.7–4.8 mg kg^?1 and Zn was 10.6–18.4 mg kg^?1, were within the safety limits set for vegetable food stuff set by Joint FAO/WHO. The bioaccessibility of Zn, an essential element, was high (40–50 %) in M. charantia and in S. cumini. In addition, the total metal contents and bioaccessible concentration of Ni, Se, Cd and Pb in these samples were measured by ICP-MS. The total Cd content in S. cumini (2.6 ± 0.2 mg kg^?1) and its bioaccessible concentration (0.6 mg kg^?1) were strikingly high as compared to the other samples. Though total Hg contents were determined by ICP-MS, but their bioaccessible concentrations were below the detection limit (0.036 mg kg^?1).     

Use of Surfactant as Mobile Phase Additive in LC for Simultaneous Determination of Metal-Pyrrolidine Dithiocarbamate Chelates

Reversed phase liquid chromatography using UV detection was developed for the simultaneous analysis of Hg(II), Pb(II), Cd(II), Ni(II), Fe(III) and V(V) ions after their complexation with pyrrolidine-dithiocarbamate (PDC). Optimum chromatographic conditions were a μ-Bondapak C₁₈ column and an isocratic mobile phase consisting of 40 mmol L^?1 SDS, 34 mmol L^?1 TBABr and 68% acetonitrile in 10 mmol L^?1 phosphate buffer pH 3.5. The separation of six PDC complexes was achieved within 8 min. Analytical performances and method validation were investigated. The detection limits ranged from 0.16 μg L^?1(Fe(III)) to 5.40 μg L^?1(Pb(II)). Recoveries obtained for all the studied samples including tap water, whole blood and vegetables were 72–98%. The results obtained from the proposed method were not significantly different compared to those obtained from atomic absorption spectrometry (P = 0.05).     

A Simple and Sensitive Method for the Detection of Trace Pb(II) and Cd(II) based on Nafion‐coated Antimony Film Electrode

Nafion‐coated antimony film electrode (NCAFE) was prepared in situ by simultaneously plated antimony with analytes, and applied to the determination of trace Pb(II) and Cd(II) in non‐deaerated solutions by differential pulse anodic stripping voltammetry (DPASV). Various experimental parameters, which influenced the response of the NCAFE to those metals, were thoroughly optimized and discussed. The results indicated that the sensitivity and resistance to surfactants at the NCAFE were remarkably improved with relative to the antimony film electrode (AFE). In the presence of 5 mg·L^?1 gelatin, the peak heights at the NCAFE showed 4‐fold enhancement for Pb and a 9‐fold enhancement for Cd over a bare AFE. Reproducibility of the sensor was satisfactory, and the relative standard deviations were 4.8% for 20 μg·L^?1 Pb and 3.2% for 25 μg·L^?1 Cd (n=15) with preconcentration time of 180 s. The determination limits (S/N=3) of this sensor were determined to be 0.15 μg·L^?1 for Pb and 0.30 μg·L^?1 for Cd with accumulation time of 300 s. The NCAFE was successfully applied to determining Pb(II) and Cd(II) in vegetable and water samples with satisfactory results.     

Determination of traces of As,Cd, Cr,Hg, Mn,Ni, Sb,Se, Sn and Pb in human hair by triple quadrupole ICP-MS

With the wide range of metallic contaminants discharged in the environment, studying the human health requires a growing number of elements to be monitored in biological samples. Hair analysis has been suggested as a suitable tool for biomonitoring environmental and occupational exposure to toxic elements. This study describes a method for the determination of 10 trace elements in hair samples using ICP-QQQ-MS. Combining the power of the MS/MS high-energy Helium mode with the MS/MS O₂ mass-shift mode, the method offers great analytical performances with detection limits reaching 0.0014 µg g^?1 for As, 0.0016 µg g^?1 for Cd, 0.012 µg g^?1 for Cr, 0.0035 µg g^?1 for Hg, 0.0055 µg g^?1 for Mn, 0.10 µg g^?1 for Ni, 0.0012 µg g^?1 for Sb, 0.0083 µg g^?1 for Sn, 0.011 µg g^?1 for Se and Pb. The accuracy of the method was tested on a human hair ERM® certified reference material. Percent recoveries varied from 91.3% and 106.9% being always in the acceptance range of 90–110%. For all analysed elements, RSD% of repeatability ranged between 0.6% and 9.0% and those of intermediate precision did not exceed the limit of 20% being always lower than 10% (except for As). The proposed method was applied for the determination of trace elements in hair samples from 20 unexposed subjects. The geometric mean levels were as follows: Cr 0.28 µg g^?1, Mn 0.30 µg g^?1, Sn 1.04µg g^?1, Sb 0.07 µg g^?1, Hg 0.42 µg g^?1, As 0.02 µg g^?1, Cd 0.03 µg g^?1, Ni 0.51 µg g^?1, Se 0.45 µg g^?1 and Pb 1.83 µg g^?1. Element concentrations were in the same range with the reported data. The reported results may be useful for environmental exposure assessment or comparisons studies when establishing reference values of trace elements in exposed population.     

Multi-wall carbon nanotubes chemically modified silica microcolumn preconcentration/separation combined with inductively coupled plasma optical emission spectrometry for the determination of trace elements in environmental waters

A novel adsorbent of multi-wall carbon nanotubes (MWCNTs) chemically modified silica (MWCNTs-silica) was synthesised and employed as the adsorbent material for solid-phase extraction (SPE) of trace Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V) in environmental water samples followed by inductively coupled plasma optical emission spectrometry detection. This material inherits the advantages of nanomaterial MWCNTs and conventional silica with dual functional groups (–NH₂ and –COOH), and avoid the problem of nanomaterial in SPE, such as high pressure. The factors affecting the separation and preconcentration of target elements such as pH, sample flow rate and volume, eluent concentration and volume were investigated. Under the optimised conditions, the detection limits for Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V) were 0.27, 0.11, 0.45, 0.91, 0.55 and 0.67 μg L^?1 with the relative standard deviations of 3.1, 5.9, 4.1, 4.0, 7.3 and 8.6% (c = 10 μg L^?1, n = 7), respectively. The adsorption capacity of MWCNTs-silica was 26.6, 70.0, 13.8, 58.0, 20.0 and 20.0 mg g^?1 for Zn(II), Cu(II), Cd(II), Cr(III), V(V) and As(V), respectively, and the prepared adsorbent could be reused more than 100 times. In order to validate the developed method, two certified reference materials of GSBZ50009-88 and GSBZ 50029-94 environmental waters were analysed and the determined values were in good agreement with the certified values. The developed method has been applied to the determination of trace elements in environmental water samples with satisfactory results.     

Molybdenum(VI) Oxide-Modified Silica Gel as a Novel Sorbent for the Simultaneous Solid-Phase Extraction of Eight Metals with Determination by Flame Atomic Absorption Spectrometry

A silica-based inorganic sorbent was synthesized by the thermal decomposition of ammonium heptamolybdate on silica and applied for the preconcentration and simultaneous determination of Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb in river water samples using a column system with flame atomic absorption spectrometry. Attenuated total reflection-Fourier transformation infrared spectroscopy, scanning electron microscopy, and electron dispersive spectroscopy were used for sorbent characterization. The effects of pH, sample volume, eluent type, eluent concentration, eluent volume, sample flow rate, and matrix ions (Al, Bi, Ca, Mg, and Zn) on the recovery of the metals in model solutions were investigated. The adsorption capacities (µmol g^?1) of SiO₂-MoO₃ were 88.96 (Cd), 169.69 (Co), 153.85 (Cr), 188.88 (Cu), 179.05 (Fe), 163.81 (Mn), 136.31 (Ni), and 38.61 (Pb). The detection limits of the method were 9.09, 10.82, 10.77, 49.57, 31.64, 6.40, 8.86, 19.15?µg L^?1 for Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb, respectively, with a preconcentration factor of 25. The developed method was used for the determination of the target metals in real samples and the recoveries for spiked samples were found to be from 91.2% to 102.9%.     

Single Laboratory Validation of a Method for the Determination of Total Inorganic Arsenic by Hydride Generation Atomic Absorption Spectrometry

The purpose of this study consists in reporting of single laboratory validation of a method for the determination of total inorganic arsenic by hydride generation atomic absorption spectrometry from natural and residual water samples. Applicability, fitness for purpose, selectivity, and sensitivity were discussed. A calibration study was realized, linear working range (0.4–4 μg·L^?1), detection (0.11 μg·L^?1), and quantification (0.38 μg·L^?1) limits being determined. It was also proven that the method is accurate and precise. Following the bottom-up approach measurement, uncertainty was estimated (method validation data were used).     

A SPE-LC-MS/MS Method for the Detection of Low Concentrations of Pharmaceuticals in Industrial Waste Streams

A SPE-LC-MS/MS method was developed and validated for the determination of three active pharmaceutical ingredients [API A (3-([2-(diaminomethyleneamino)thiazol-4-yl]methylthio)-N′-sulfamoyl propanimid amide, API B 5-[(2 R)-2-[2-(2-ethoxyphenoxy)ethylamino]propyl]-2-methoxybenzenesulfonamide hydrochloride, API C 1-azabicyclo[2.2.2]octan-8-yl (1S)-1-phenyl-3,4-dihydro-1H-isoquinoline-2-carboxylate] in the wastewater of a chemical synthesis production facility. The SPE-LC-MS/MS method was validated in actual influent and effluent samples. Linearity, LOD, LOQ, repeatability, intermediate precision, and recovery were determined. An LOQ of 400 μg · L^?1, 1.0 μg · L^?1, and 6 μg · L^?1, repeatability of 2.5% CV, 14.8% CV, and 11.9% CV, intermediate precision of 7.8% CV, 11.0% CV, and 8.7% CV and SPE recovery of 114%, 103%, and 91% was determined for API A, B, and C, respectively, in influent. An LOQ of 400 μg · L^?1, 0.8 μg · L^?1, and 6 μg · L^?1, repeatability of 2.0% CV, 11.0% CV, and 10.9% CV, intermediate precision of 1.7% CV, 6.8% CV, and 10.2% CV and SPE recovery of 116%, 96%, and 115% was established for API A, B, and C, respectively, in effluent. Coefficients of correlation for each analyte were >0.9301 confirming the linearity of the method. The LC-MS/MS method was used for an on-going monitoring program for these pharmaceuticals in wastewater. The method development techniques, validation procedures, and results from real wastewater samples are presented in this paper.     

Screening of foods and related products for toxic elements with a portable X-ray tube analyzer

Capabilities of a portable X-ray tube-based analyzer were evaluated for screening foods, thin films, and ceramic glazes for toxic elements. A beverage spiked with Cr, Cu, and As and cocoa powder spiked with As and Pb could easily be distinguished from unadulterated products when analyzed through their original container walls. With calibration, results for thin films and ceramic glazes yielded accurate Pb results. Limits of detection (LODs) were 0.2–15 and 15 μg cm^?2, respectively, for Pb and Cd in thin films and about 2 μg cm^?2 for Pb in glazes. With analysis times of 0.5–1 min, sensitivities and LODs were superior to those obtained with radioisotopic X-ray fluorescence analysis.     

Synthesis of a New Cu(II)-Ion Imprinted Polymer for Solid Phase Extraction and Preconcentration of Cu(II)

A new Cu(II)-ion imprinted polymer (IIP) has been synthesized by copolymerizing salicylic acid and formaldehyde as a monomer and crosslinker, respectively in the presence of Cu(II)-4-(2-pyridylazo) resorcinol complex. The imprinted Cu(II) ions were completely removed by leaching the IIP with 0.05 M EDTA. The maximum adsorption capacity for Cu(II) ions was 310 μg g^?1 at pH 6. The IIP was repeatedly used in adsorption–desorption experiments for seven times with recoveries ~95%. The relative selectivity factor (α _r) values of Cu(II)/Zn(II), Cu(II)/Cd(II), Cu(II)/Ni(II) and Cu(II)/Co(II) are 3.17, 2.90, 2.47 and 3.37, respectively. The detection limit corresponding to three times the standard deviation of the blank was found to be 3.0 μg L^?1. The developed IIP has also been tested for preconcentration and recovery of Cu(II) ions from water samples.     

Preparation, characterization, and application of a new thiol-functionalized ionic liquid for highly selective extraction of Cd(II)

A highly selective thiol-functionalized ionic liquid (thiol-FIL) was synthesized and characterized by FT-IR and ESI mass spectroscopy. The capability of thiol-FIL to extract Cd(II), Ni(II), Cr(III) and Pb(II) was evaluated. It is found that thiol-FIL possesses high selectivity for Cd(II), and this has led to a method for determination of Cd(II) by flame atomic absorption spectrometry that is free of interferences by up to a 1,000-fold excess of Na(I), Mg(II), Ca(II), Mn(II), Fe(III), Al(III), Cu(II), Zn(II), Ni(II), Cr(III), Co(II), As(III), Pb(II), and Hg(II). With extraction equilibrium time of 1 min, a good linearity (r = 0.9998) and a detection limit of 0.39 μg?L^?1 were obtained. The precision (RSD) for 11 replicate measurements of 10 μg?L^?1 Cd was 1.6%. The method was validated using certified reference materials. The recoveries of cadmium in spiked real samples ranged from 97% to 102%.     

Synthesis and characterisation of novel chelating resin for selective preconcentration and trace determination of Pb(II) ions in aqueous samples by innovative microsample injection system coupled flame atomic absorption spectrometry

Expanded polystyrene (EPS) foam waste (white pollutant) was utilised for the synthesis of novel chelating resin i.e. EPS-N = N-α-Benzoin oxime (EPS-N = N-Box). The synthesised resin was characterised by FT-IR spectroscopy, elemental analysis, and thermogravimetric analysis. A selective method for the preconcentration of Pb(II) ions on EPS-N = N-Box resin packed in mini-column was developed. The sorbed Pb(II) ions were eluted with 5.0 mL of 2.0 mol L^?1 HCl and determined by microsample injection system coupled flame atomic absorption spectrometry (MIS-FAAS). The average recovery of Pb(II) ions was achieved 95.5% at optimum parameters such as pH 7, resin amount 400 mg, flow rates 1.0 mL min^?1 (of eluent) and3.0 mL min^?1 (of sample solution). The total saturation capacity of the resin, limit of detection (LOD) and limit of quantification (LOQ) of Pb(II) ions were found to be 30 mg g^?1, 0.033 μg L^?1 and 0.107 μg L^?1, respectively with preconcentration factor of 300. The accuracy, selectivity and validation of the method was checked by analysis of sea water (BCR-403), wastewater (BCR-715) and Tibet soil (NCS DC-78302) as certified reference materials (CRMs). The proposed method was applied successfully for the trace determination of Pb(II) ions in aqueous samples.