Cold Vapor Atomic Absorption Spectrometry Research Articles

Validation of a new and cost-effective method for mercury vapor removal based on silver nanoparticles coating on micro glassy balls

Exposure to mercury vapor (Hg0) causes serious health problem in human body. In this study, a novel and applied method based on solid gas phase extraction (SGPE) with silver nanoparticles (AgNPs) coating on micro glassy balls (MGB) was used for Hg0 removal from artificial air. In bench scale set up, the mercury vapor in air composition was produced by mercury vapor generation system (HgGS) and restored in polyethylene air bag (5 Li). In optimized conditions, the mercury vapor in air bag, passed through AgNPs-MGB and absorbed on it. Then, the mercury was completely desorbed from AgNPs by increasing temperature up to 245 °C and online determined by cold vapor atomic absorption spectrometry (CV-AAS). By proposed procedure, the method recovery and capacity of AgNPs were obtained 98% and 91.8 mg g−1, respectively. A simple, fast and low cost synthesis of AgNPs causes, the SGPE introduce as a cost-effective method for mercury vapor removal from air. Validation of methodology was confirmed using ultra trace mercury analyzer (MC3000).

Novel extraction induced by microemulsion breaking: a model study for Hg extraction from Brazilian gasoline

This paper proposes a novel approach for the extraction of Hg from Brazilian gasoline samples: extraction induced by microemulsion breaking (EIMB). In this approach, a microemulsion is formed by mixing the sample with n-propanol and HCl. Afterwards, the microemulsion is destabilized by the addition of water and the two phases are separated: (i) the top phase, containing the residual gasoline and (ii) the bottom phase, containing the extracted analyte in a medium containing water, n-propanol and the ethanol originally present in the gasoline sample. The bottom phase is then collected and the Hg is measured by cold vapor atomic absorption spectrometry (CV-AAS). This model study used Brazilian gasoline samples spiked with Hg (organometallic compound) to optimize the process. Under the optimum extraction conditions, the microemulsion was prepared by mixing 8.7mL of sample with 1.2mL of n-propanol and 0.1mL of a 10molL−1 HCl solution. Emulsion breaking was induced by adding 300µL of deionized water and the bottom phase was collected for the measurement of Hg. Six samples of Brazilian gasoline were spiked with Hg in the organometallic form and recovery percentages in the range of 88–109% were observed.

<b>Impact of exposure to low levels of mercury on the health of dental workers

This work evaluated the impact of exposure to mercury on the health of workers comparing dentists and dental assistants exposed to mercury by handling amalgam in a public dental clinic with a reference group which, in private offices, did not make use of the metal in their professional routine. Data collection included mercury levels in urine and air samples determined by cold vapor atomic absorption spectrometry, questionnaires and direct observation. The difference between urine and air samples in both groups was statistically significant while mercury levels in air and urine showed positive associations. Mercury concentration in urine correlated with gender, practice time, and age of workers. Half of those exposed had complaints compatible with mercury contamination. Among the exposed, the most common complaints were cognitive and neurocognitive symptoms. Correlations between symptoms and exposure time and also number of amalgam fillings placed per week were positive. Amalgam handling resulted in environmental and biological contamination by mercury.

The Presence of Mercury in the Tissues of Mallards (Anas platyrhynchos L.) from W\u0142oc\u0142awek Reservoir in Poland

The study aimed at determining the degree of mercury contamination of mallards, game waterbirds migrating from the regions of the unknown degree of contamination and establishing whether the consumption of their meat comprises a hazard to human health in view of the binding norms concerning the mercury content in food products. The investigations were carried out on 30 mallards shot during the duck shooting season in which mercury concentrations in the muscles, liver, and kidneys were determined using the cold vapor atomic absorption spectrometry (CV-AAS) method. The mean Hg concentration in the investigated tissues in all birds studied amounted to 0.110, 0.154, and 0.122 mg kg−1 for the muscles, kidneys, and liver, respectively. The study indicated statistically significant (p ≤ 0.01) positive correlation between all of the organs examined. Animals were divided into two groups differing in both absolute values of Hg concentrations and those measured in individual tissues. In particular organs of birds representing the first group, the presence of highly significant correlation (p ≤ 0.01) was observed in all organs examined. In the second group, highly significant positive correlation between Hg concentrations in the liver and kidneys and highly significant negative dependence between the liver and muscles was noted. The examinations revealed that some birds must have come from regions of a high degree of mercury contamination.

On the distribution of trace element concentrations in multiple bone elements in 10 Danish medieval and post-medieval individuals.

The differences in trace element concentrations among 19 different bone elements procured from 10 archaeologically derived human skeletons have been investigated. The 10 individuals are dated archaeologically and some by radiocarbon dating to the medieval and post-medieval period, an interval from ca. AD 1150 to ca. AD 1810. This study is relevant for two reasons. First, most archaeometric studies analyze only one bone sample from each individual; so to what degree are the bones in the human body equal in trace element chemistry? Second, differences in turnover time of the bone elements makes the cortical tissues record the trace element concentrations in equilibrium with the blood stream over a longer time earlier in life than the trabecular. Therefore, any differences in trace element concentrations between the bone elements can yield what can be termed a chemical life history of the individual, revealing changes in diet, provenance, or medication throughout life. Thorough decontamination and strict exclusion of non-viable data has secured a dataset of high quality. The measurements were carried out using Inductively Coupled Plasma Mass Spectrometry (for Fe, Mn, Al, Ca, Mg, Na, Ba, Sr, Zn, Pb and As) and Cold Vapor Atomic Absorption Spectroscopy (for Hg) on ca. 20 mg samples. Twelve major and trace elements have been measured on 19 bone elements from 10 different individuals interred at five cemeteries widely distributed in medieval and renaissance Denmark. The ranges of the concentrations of elements were: Na (2240-5660 µgg-1 ), Mg (440-2490 µgg-1 ), Al (9-2030 µgg-1 ), Ca (22-36 wt. %), Mn (5-11450 µgg-1 ), Fe (32-41850 µgg-1 ), Zn (69-2610 µgg-1 ), As (0.4-120 µgg-1 ), Sr (101-815 µgg-1 ), Ba (8-880 µgg-1 ), Hg (7-78730 ngg-1 ), and Pb (0.8-426 µgg-1 ). It is found that excess As is mainly of diagenetic origin. The results support that Ba and Sr concentrations are effective provenance or dietary indicators. Migrating behavior or changes in diet have been observed in four individuals; non-migratory or non-changing diet in six out of the 10 individuals studied. From the two most mobile (most changing diet) individuals in the study, it is deduced that the fastest turnover is seen in the trabecular tissues of the long bones and the hands and the feet, and that these bone elements have higher turnover rates than centrally placed trabecular bone tissue, such as from the ilium or the spine. Comparing Sr and published bone turnover times, it is concluded that the differences seen in Sr concentrations are not caused by diagenesis, but by changes of diet or provenance. Finally, it is concluded that there can be two viable interpretations of the Pb concentrations, which can either be seen as an indicator for social class or a temporal development of increased Pb exposure over the centuries.

Polythionine-decorated magnetic nanoparticles as a robust and highly effective sorbent for mercury determination in environmental water samples

ABSTRACTExtraction, pre-concentration and determination of trace amounts of mercury ions from water samples were investigated by magnetic solid phase extraction (MSPE) method using Fe3O4 nanoparticles decorated with polythionine as an adsorbent. A simple chemical synthesis by catalytic reaction of thionine in the presence of FeCl3 and hydrogen peroxide was used for preparation of the magnetic sorbent. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometer analysis and Fourier transform infrared spectroscopy were used to characterise the adsorbent. Mercury ions were determined by cold vapour atomic absorption spectrometry. The parameters for MSPE procedure, such as pH of the extraction solution, adsorption time, weight adsorbent, elution conditions (type, concentration and volume of the eluent), volume of the sample solution and effects of coexisting ions were investigated. The obtained optimal conditions were: sample pH of 4; sorbent amount of 4 mg; sorption time of 20 min; elution solvent of HNO3 (0.3 mol L−1)/thiourea (2% w/v) with volume of 2 mL, and breakthrough volume of 400 mL. A good linearity in the concentration range of 0.025–40 µg L−1 (R2 > 0.999) with the pre-concentration factor of 198 was obtained. The limits of detection and quantification were achieved as 0.008 and 0.025 µg L−1, respectively. Furthermore, sea and river water samples were analysed and good recoveries (97.1–99.6%) were obtained.

Ultrasound-assisted dispersive micro solid-phase extraction with nano-TiO2 as adsorbent for the determination of mercury species

The combination of ultrasound-assisted dispersive micro solid-phase extraction (USA DMSPE), with the use of TiO2 nanoparticles (NPs) as adsorbent, with cold vapor atomic absorption spectrometry (CV AAS) is proposed for preconcentration and determination of mercury species (Hgtotal, Hg2+ and CH3Hg+) in biological, geological and water samples. The experimental parameters including the amount of TiO2 NPs, pH of sample solution, ultrasonication and centrifugation time, TiO2 slurry solution preparation before injection to CV AAS were investigated. Effective preconcentration of trace mercury with 10mg of TiO2 was achieved in pH 7.5. After extraction, adsorbent with analytes was mixed with 500μL of 1molL−1 HNO3 to prepare slurry solution. The concentration limit of detection was 0.004ngmL−1 for Hg2+. The achieved preconcentration factor was 35. The relative standard deviations (RSDs, %) for mercury species in real samples were 4–20%. The accuracy of this method was evaluated by analyses of certified reference materials: DOLT-2 (Dogfish Liver), IAEA-085 (Human hair), SRM 2709 (San Joaquin Soil), SRM 2711 (Montana Soil) and SRM 2704 (Buffalo River Sediment). The measured mercury species contents in reference materials were in satisfactory agreement with the added amounts (according to the t-test for a 95% confidence level). The presented method has been successfully applied for the determination of mercury species in real water samples (lake and river water).

On the use of certified reference materials for assuring the quality of results for the determination of mercury in environmental samples

This work focused on the development and validation of methodologies for the accurate determination of mercury in environmental samples and its further application for the preparation and certification of new reference materials (RMs). Two certified RMs ERM-CC580 (inorganic matrix) and ERM-CE464 (organic matrix) were used for the evaluation of digestion conditions assuring the quantitative recovery of mercury. These conditions were then used for the digestion of new candidates for the environmental RMs: bottom sediment (M_2 BotSed), herring tissue (M_3 HerTis), cormorant tissue (M_4 CormTis), and codfish muscle (M_5 CodTis). Cold vapor atomic absorption spectrometry (CV AAS) and inductively coupled plasma mass spectrometry (ICP MS) were used for the measurement of mercury concentration in all RMs. In order to validate and assure the accuracy of results, isotope dilution mass spectrometry (IDMS) was applied as a primary method of measurement, assuring the traceability of obtained values to the SI units: the mole, the kilogram, and the second. Results obtained by IDMS using n(200Hg)/n(202Hg) ratio, with estimated combined uncertainty, were as follows: (916 ± 41)/[4.5 %] ng g−1 (M_2 BotSed), (236 ± 14)/[5.9 %] ng g−1 (M_3 HerTis), (2252 ± 54)/[2.4 %] ng g−1 (M_4 CormTis), and (303 ± 15)/[4.9 %] ng g−1 (M_CodTis), respectively. Different types of detection techniques and quantification (external calibration, standard addition, isotope dilution) were applied in order to improve the quality of the analytical results. The good agreement (within less than 2.5 %) between obtained results and those derived from the Inter-laboratory Comparison, executed by the Institute of Nuclear Chemistry and Technology (Warsaw, Poland) on the same sample matrices, further validated the analytical procedures developed in this study, as well as the concentration of mercury in all four new RMs. Although the developed protocol enabling the metrological certification of the reference value was exemplified by the determination of mercury in environmental samples, it could be considered as valid for any certification procedure required whenever new certified RMs are introduced.

Mineralogy and geochemistry of different morphological pyrite in Late Permian coals, South China

The mineralogical and morphological characteristics, concentration of major and trace elements, and sulfur isotopic composition of three pyrite and two coal samples in the Upper Permian high-sulfur coals from Xingren, Zhijin, and Hefeng mining area, South China, were investigated, by using optical microscopy, field emission-scanning electron microscopy in conjunction with an energy-dispersive X-ray spectrometer (FE SEM-EDS), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), cold vapor atomic absorption spectrometry (CVAAS), and isotopic ratio mass spectrometer. The pyrite in Xingren and Zhijin coals mainly occurs as nodular, lens-shaped, thin-layer, and massive forms, and it occurs mainly as fine vein fillings in the Hefeng coals. Microscopically, pyrite in the coals from Xingren, Zhijin, and Hefeng mainly occurs as framboidal, cell-filling, and vein-filling forms, respectively. There is a distinct difference in X-ray powder diffractogram and diffraction data of the three pyrite samples. There is a maximum diffraction peak (2.709 A) in pyrite in the coals from Xingren and (2.707 A) in pyrite in the coals from Zhijin; however, the maximum diffraction peak is 3.343 A in pyrite in the coals from Hefeng. The average unit cell length (a0) is 5.4169 A for the Xingren pyrite, 5.4159 A for the Zhijin pyrite, and 5.4170 A for the Hefeng pyrite. The ratio of S/Fe is 2.16 for the Xingren pyrite, 2.09 for the Zhijin pyrite, and 2.01 for the Hefeng pyrite. Copper (701 μg/g), Ni (369 μg/g), and Co (29.6 μg/g) concentrated in the Hefeng pyrite. The concentration of As is 126, 19.6, and 19.1 μg/g in the Hefeng, Zhijin, and Xingren pyrite, respectively. Mercury is 11.7 μg/g in the Xingren pyrite, 2.79 μg/g in the Zhijin pyrite, and 0.512 μg/g in the Hefeng pyrite. There is a clear tendency that elements Cu, Ni, Co, Cr, Se, Mo, and As are significantly enriched in the Hefeng pyrite. Mercury is greatly enriched in the Xingren pyrite, and Zn is enriched in Zhijin pyrite. Rare earth elements and yttrium (REY) are not abundant (8.276 μg/g) in the Hefeng pyrite and are characterized by maximum positive anomaly of Eu (Eu/Eu* = 6.54). The δ34S value is −26.9 ‰ in the Xingren pyrite, +3.8 ‰ in the Zhijin pyrite, and +3.7 ‰ in the Hefeng pyrite. The trace elements in the Hefeng pyrite and coal are As (126 and 6.1 μg/g), Hg (0.512 and 0.158 μg/g), Zn (276 and 56.7 μg/g), Se (16.5 and 1.07 μg/g), Mo (45.5 and 9.93 μg/g), Cu (701 and 37.8 μg/g), Ni (369 and 16.9 μg/g), Co (29.6 and 8.63 μg/g), Sb (2.64 and 0.742 μg/g), Cd (3.49 and 0.366 μg/g), and Pb (62.8 and 33.5 μg/g), demonstrating that these potentially toxic trace elements were mainly concentrated in pyrites. The strongly positive Eu anomaly (Eu/Eu* = 6.54) in the netted pyrite vein filled in the cleats of the Hefeng coal may be the product of epigenetic hydrothermal fluid.

GPX1 Pro198Leu polymorphism and GSTM1 deletion do not affect selenium and mercury status in mildly exposed Amazonian women in an urban population

Mercury is potent toxicant element, but its toxicity can be reduced by forming a complex with selenium for safe excretion. Considering the impact of mercury exposure in the Amazon region and the possible interaction between these two elements, we aimed to assess the effects of Pro198Leu polymorphism to GPX1 and GSTM1 deletion, on mercury levels in a population from Porto Velho, an urban locality in the Brazilian Amazon region. Two hundred women from the capital city of Rondônia state were recruited for this study with 149 deemed suitable to participate. We assessed dietary intake using 24-hour recall. Selenium levels in plasma and erythrocytes were measured using hydride generation quartz tube atomic absorption spectroscopy and total hair mercury using cold vapor atomic absorption spectrometry. Oxidative stress parameters (GPx activity, oxygen radical absorbency capacity [ORAC] and malondialdehyde [MDA]) were also analyzed. All participants were genotyped for Pro198Leu polymorphism and GSTM1 deletion. We observed that this population presented high prevalence of selenium deficiency, and also low levels of mercury, likely due to food habits that did not include selenium-rich food sources or significant consumption of fish (mercury biomagnifiers) regularly. Univariate statistical analysis showed that Pro198Leu and GSTM1 genotypes did not affect selenium and mercury levels in this population. Pro198Leu polymorphism and GSTM1 deletion had no effect on mercury levels in mildly exposed people, suggesting these genetic variants impact mercury levels only in highly exposed populations.

Chemometric approach to evaluate element distribution in muscle, liver and fish bone of roach (Rutilus rutilus), silver bream (Blicca bjoerkna) and crucian carp (Carassius carassius) from Swarzędzkie Lake (Poland) using ICP-MS and FIAS-CVAAS techniques

ABSTRACTThe content of elements in fish tissues and organs from Swarzędzkie Lake was investigated in order to evaluate the possible risk associated with their consumption by animals as well as humans. Samples of muscle, liver and fish bone of three fish species; roach (Rutilus rutilus), silver bream (Blicca bjoerkna) and crucian carp (Carassius carassius) were collected from seine catches undertaken as part of the biomanipulation of Swarzędzkie Lake. Element concentration (Al, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) was determined by inductively coupled plasma mass spectrometry (ICP-MS), with the exception of Hg where the flow injection analysis system cold vapour atomic absorption spectrometry (FIAS-CVAAS) was applied. The study indicated a large variation in the occurrence of the investigated elements in different parts of the fish body. The highest content of Al and Zn was stated in all fish organs for each fish species. The majority of the applied statistical and chemometric methods (e.g., PCA, CA) refer to roach since we had a large number of data for this species. The obtained results were assessed in terms of their accuracy and precision using certified reference material of Fish Muscle ERM BB422.

Silver ion modulated CdS quantum dots for highly selective detection of trace Hg2+

In the present work, water-soluble cysteamine capped-CdS quantum dots (Cys-CdS QDs) modulated with Ag+ were employed as fluorescence sensors for the determination of Hg2+ ion. The synthesized Cys-CdS QDs exhibit relatively weak fluorescence emission, however, the emission was enhanced exclusively in the presence of Ag+ compared to other metal ions. Moreover, the fluorescence intensity of the Ag+ modulated Cys-CdS QDs (Ag+@Cys-CdS QDs) was significantly quenched in the presence of trace amounts of Hg2+ due to high-affinity metallophilic interactions between Hg2+ and Ag+. Based on this specific interaction, good selectivity towards the detection of Hg2+ over other metal ions was achieved. To gain the best sensing performance, parameters affecting the Hg2+ detection sensitivity were studied and optimized in detail. Under the optimized conditions, the fluorescence intensity of Ag+@Cys-CdS QDs decreased linearly with Hg2+ concentration in the range of 0.1–3.5μM, with a limit of detection of around 0.09μM. The applicability of this sensor was demonstrated by the determination of Hg2+ in drinking water samples, corresponding well with results of cold-vapor atomic absorption spectrometry.

Electromembrane extraction and anodic stripping voltammetric determination of mercury(II) using a glassy carbon electrode modified with gold nanoparticles

This study presents a method for the selective determination of Hg(II) using electromembrane extraction (EME), followed by square wave anodic stripping voltammetry (SWASV), using a gold nanoparticle-modified glassy carbon electrode, (AuNP/GCE). By applying an electrical potential of typically 60 V for 12 min through a thin supported liquid membrane (1-octanol), Hg(II) ions are extracted from a donor phase (i.e., the sample solution) to an acidic acceptor solution (15 μL) placed in the lumen of a hollow fiber. The influences of experimental parameters during EME were optimized using face-centered central composite design. The calibration plot, established at a working voltage of 0.55 V (vs. Ag/AgCl), extends from 0.2 to 10 μg.L−1 of Hg(II). The limit of detection, at a signal to noise ratio of 3, is 0.01 μg.L−1 and the relative standard deviations (for 5 replicate determinations at 3 concentration levels) are between 7.5 and 8.7 %. The method was successfully applied to the determination of Hg(II) in spiked real water samples to give recoveries ranging from 89 to 97 %. The results were validated by cold vapor atomic absorption spectroscopy.

Evaluation of vulnerability of Suillus variegatus and Suillus granulatus mushrooms to sequester mercury in fruiting bodies

ABSTRACTThis work determined the mercury (Hg) contents and bioconcentration potential of two Suillus mushrooms, and the probable dietary intake of this element from a mushroom meal. The determination of total Hg content of fungal and soil samples was performed using cold-vapour atomic absorption spectroscopy by a direct sample thermal decomposition coupled with gold wool trap of Hg and its further desorption and quantitative measurement at a wavelength of 253.7 nm. The median values of Hg contents (mg kg−1 dry biomass) in 213 specimens of S. variegatus from 12 background areas varied widely from 0.087 to 0.51 for caps and from 0.041 to 0.24 for stipes. In 52 specimens of S. granulatus, the Hg contents ranged from 0.30 to 0.41 for caps and from 0.058 to 0.14 for stipes. Both species could be classified as moderate accumulators of Hg and the median bioconcentration factor values ranged from 7.0 to 14 (caps) and 2.1 to 13 (stipes) for S. variegatus and 9.5 (caps) and 1.3 (stipes) for S. granulatus. The estimated intake rates of Hg with the consumption of 300-g caps were from 0.0026 to 0.015 per capita or from 0.000037 to 0.00022 mg kg−1 body mass and this do not indicate any cause for concern associated with eating a meal once or more in a week during the mushrooming season.

Removal of mercury(II) ions in aqueous solution using the peel biomass of Pachira aquatica Aubl: kinetics and adsorption equilibrium studies.

Mercury is a highly toxic substance that is a health hazard to humans. This study aims to investigate powders obtained from the peel of the fruit of Pachira aquatica Aubl, in its in natura and/or acidified form, as an adsorbent for the removal of mercury ions in aqueous solution. The materials were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The infrared spectra showed bands corresponding to the axial deformation of carbonyls from carboxylic acids, the most important functional group responsible for fixing the metal species to the adsorbent material. The thermograms displayed mass losses related to the decomposition of three major components, i.e., hemicellulose, cellulose, and lignin. The adsorption process was evaluated using cold-vapor atomic fluorescence spectrometry (CV AFS) and cold-vapor atomic absorption spectrometry (CV AAS). Three isotherm models were employed. The adsorption isotherm model, Langmuir-Freundlich, best represented the adsorption process, and the maximum adsorption capacity was predicted to be 0.71 and 0.58 mg g(-1) at 25 °C in nature and acidified, respectively. Adsorption efficiencies were further tested on real aqueous wastewater samples, and removal of Hg(II) was recorded as 69.6 % for biomass acidified and 76.3 % for biomass in nature. Results obtained from sorption experiments on real aqueous wastewater samples revealed that recovery of the target metal ions was very satisfactory. The pseudo-second-order model showed the best correlation to the experimental data. The current findings showed that the investigated materials are potential adsorbents for mercury(II) ion removal in aqueous solution, with acidified P. aquatica Aubl being the most efficient adsorbent.

Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis

A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m−3 and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%.

Magnetic dispersive micro solid-phase extraction for trace mercury pre-concentration and determination in water, hemodialysis solution and fish samples

A new preconcentration method, magnetic dispersive micro solid phase extraction (MDMSPE) developed for separation and determination of mercury. In this technique, an appropriate mixture of extraction solvent, disperser solvent and nanomagnetite (Fe3O4)/chelating agent 1-(2-ethoxyphenyl)-3-(4-ethoxyphenyl) triazene functionalized multi-walled carbon nanotubes with silica shell, as an adsorbent injected rapidly into an aqueous solution containing mercury. After the proper contact time, the nano-adsorbent separated from the aqueous phase by applying magnetic field outside of the vial and transferred to another vial with the elution solvent. The residual solution determined by cold vapour atomic absorption spectroscopy. The main factors affected the preconcentration of mercury investigated and optimized, such as extraction and disperser solvent type, adsorbed amount, sample pH value, effluent concentration, extraction time, the volume of chelating agents and temperature. The adsorption equilibrium data obeyed the Langmuir isotherm models and the kinetic data were well suited to the pseudo-second-order model. Thermodynamic studies revealed the endothermic nature of the procedure. Under the optimum experimental conditions, the detection limit for Hg(II) found to be 1.5±0.27ngmL−1 and its limit of quantification (LOQ) was 5.0±0.32ngmL−1 (n=5). The linear range of the calibration curve was 9±0.51–1000±0.03ngmL−1with a correlation coefficient of 0.9994.

Preconcentration of mercury on polyaniline expands the horizon for energy dispersive X‐ray fluorescence determination

Hg(II) was sorbed on polyaniline from aqueous solutions, followed by determination using energy dispersive X‐ray fluorescence spectrometry. Distribution coefficient of Hg(II) on polyaniline was about 4 × 103 in water, whereas distribution coefficient was 1.2 × 104 at 0.1 M HCl and decreased drastically with increase in HCl concentration. Rapid kinetics of sorption was evinced by the 80% uptake within the initial 1 min and quantitative sorption within 5 min of equilibration. The sorption was found to follow Langmuir isotherm model, and the Langmuir capacity was calculated as 19.7 mg g−1. The ability of polyaniline to form stable and homogeneous pellets facilitated the energy dispersive X‐ray fluorescence determination without recourse to elution. Detection limit of Hg was found to be 22 ng, considering 100 mg pellet of polyaniline. The apparent detection limit was 6 pg, as the preconcentration factor of Hg(II) on polyaniline was 4 × 103. The developed method is at par with the established method for mercury determination, namely, cold vapor atomic absorption spectrometry. Accuracy of the method was established by the analysis of the International Atomic Energy Agency reference materials, namely, hair and lichen, for Hg(II). Copyright © 2016 John Wiley & Sons, Ltd.

Metallic elements (Ca, Hg, Fe, K, Mg, Mn, Na, Zn) in the fruiting bodies of Boletus badius

The aim of this study was to investigate and compare the levels of eight metallic elements in the fruiting bodies of Bay Bolete (Boletus badius; current name Imleria badia) collected from ten sites in Poland to understand better the value of this popular mushroom as an organic food. Bay Bolete fruiting bodies were collected from the forest area near the towns and villages of Kętrzyn, Poniatowa, Bydgoszcz, Pelplin, Włocławek, Żuromin, Chełmno, Ełk and Wilków communities, as well as in the Augustów Primeval Forest. Elements such as Ca, Fe, K, Mg, Mn, Na and Zn were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), and mercury by cold vapor atomic absorption spectrometry (CV-AAS). This made it possible to assess the nutritional value of the mushroom, as well as possible toxicological risks associated with its consumption. The results were subjected to statistical analysis (Kruskal–Wallis test, cluster analysis, principal component analysis).

Ultrasound assisted extraction for the determination of mercury in sediment samples employing cold vapour atomic absorption spectrometry

An extraction procedure involving ultrasound assisted radiation was proposed for the determination of mercury in river sediment samples using cold vapour atomic absorption spectrometry (CV AAS).