Determination Of Total Mercury Research Articles

Determination of Total Mercury in Fish Tissue Using a Low-Cost Cold Vapor Capacitively Coupled Plasma Microtorch Optical Emission Microspectrometer: Comparison with Direct Mercury Determination by Thermal Decomposition Atomic Absorption Spectrometry

A method for total Hg determination in fish tissue using cold vapor capacitively coupled plasma microtorch optical emission spectrometry was evaluated. The low-cost miniaturized analytical system includes a low power plasma microtorch (10 W) and low Ar consumption (150 ml min−1) and a QE65Pro microspectrometer as detector. Lyophilized fish tissues were microwave-assisted digested in HNO3–H2O2 mixture, brought in 5 % (v/v) HCl, then Hg vapor was chemically generated with 20 % SnCl2 solution stabilized in 15 % (v/v) HCl. The figures of merit of the proposed method were evaluated by analyzing certified reference materials and test samples and compared to those of the well-established thermal decomposition atomic absorption spectrometry method. The analytical characteristics (limits of detection and quantification, precision, and accuracy) comply with requirements for Hg determination in seafood set out in Decisions 2007/333/EC and 2002/657/EC. The limits of detection and quantification of the proposed method were 3 and 9 μg kg−1 Hg in dry mass, similar to those in thermal decomposition atomic absorption spectrometry. The precision was between 1.8 and 5.5 % for concentrations in the range 0.18–0.76 mg kg−1 Hg, while the accuracy was 99.7 ± 3.0 %. The significance tests revealed no difference between the results obtained by the two methods. The proposed miniaturized spectrometric equipment could be the subject of prototyping as low-cost instrumentation for designed applications in seafood control.

Determination of total mercury in nuts at ultratrace level

Total mercury, at μgkg−1 level, was determined in different types of nuts (cashew nut, Brazil nuts, almond, pistachio, peanut, walnut) using a direct mercury analyser after previous sample defatting and by cold vapour atomic fluorescence spectrometry. There is not enough sensitivity in the second approach to determine Hg in previously digested samples due to the strong matrix effect. Mercury levels in 25 edible nut samples from Brazil and Spain were found in the range from 0.6 to 2.7μgkg−1 by using the pyrolysis of sample after the extraction of the nut fat. The accuracy of the proposed method was confirmed by analysing certified reference materials of Coal Fly Ash-NIST SRM 1633b, Fucus-IAEA 140 and three unpolished Rice Flour NIES-10. The observed results were in good agreement with the certified values. The recoveries of different amounts of mercury added to nut samples ranged from 94 to 101%. RSD values corresponding to three measurements varied between 2.0 and 14% and the limit of detection and quantification of the method were 0.08 and 0.3μgkg−1, respectively.

Determination of total mercury in fish and sea products by direct thermal decomposition atomic absorption spectrometry

A Zeeman Mercury analyzer Model RA-915+ (Lumex, St. Petersburg, Russia), based on the direct thermal evaporation of Hg from solid samples was used for developing a method for the determination of Hg in fish and other seafood. The method does not require any chemical pretreatment of samples. This greatly simplifies the analytical procedure and minimises potential sources of contamination. The limit of detection (3s criteria) and limit of quantification (10s criteria) for the determination of Hg in wet fish samples with a mass of 250mg was found to be 0.6ngg−1 and 2.0ngg−1, respectively. Time taken for the analysis of one sample is about 3min. The accuracy of the method was confirmed by the analysis of certified reference materials of different types and by comparative analysis of fish samples using the accepted method of cold vapour generation. Excellent correspondence to the certified values was obtained. It was found that the mercury concentration in most fish species purchased from the Tshwane fish market were below the 0.5mgkg−1 (500ngg−1), wet weight, recommended by the FAO/WHO. It was also found that the direct thermal decomposition method for the determination of mercury is a more environmentally friendly alternative since it does not generate chemical waste.

In vitro study of thimerosal reactions in human whole blood and plasma surrogate samples

Because of its bactericidal and fungicidal properties, thimerosal is used as a preservative in drugs and vaccines and is thus deliberately injected into the human body. In aqueous environment, it decomposes into thiosalicylic acid and the ethylmercury cation. This organomercury fragment is a potent neurotoxin and is suspected to have similar toxicity and bioavailability like the methylmercury cation. In this work, human whole blood and physiological simulation solutions were incubated with thimerosal to investigate its behaviour and binding partners in the blood stream. Inductively coupled plasma with optical emission spectrometry (ICP-OES) was used for total mercury determination in different blood fractions, while liquid chromatography (LC) coupled to electrospray ionisation time-of-flight (ESI-TOF) and inductively coupled plasma-mass spectrometry (ICP-MS) provided information on the individual mercury species in plasma surrogate samples. Analogous behaviour of methylmercury and ethylmercury species in human blood was shown and an ethylmercury-glutathione adduct was identified.

Analytical performances of nanostructured gold supported on metal oxide sorbents for the determination of gaseous mercury.

Nanostructured gold supported TiO2, ZnO, and Al2O3 materials (1% w/w Au) were tested as sorbents for gaseous mercury (Hg) trapping and preconcentration. Their analytical performances were first compared with the one of traditional gold wool trap for the quantification of Hg standards injected into the argon flow followed by thermal desorption at 600°C and CVAFS detection. Good linearity and reproducibility were obtained, especially for Au/TiO2 material (R 2 = 0.995; slope: 1.39) in the volume range of 10 to 60 µL (132–778 pg Hg). This latter even showed a better performance compared to pure Au in the volume range of 10 to 100 µL (132–1329 pg Hg) when the carrier gas flow was increased from 60 to 100 mL min−1. The method detection limit (MDL) obtained with Au/TiO2 trap (0.10 pg Hg0 L−1) was suitable for total gaseous mercury (TGM) determination. Au/TiO2 was, therefore, used in trapping and determining TGM in collected air samples. TGM values in the samples ranged from 6 to 10 ng m−3. Similar results were obtained with the commercial gold-coated sand trap which showed an average TGM concentration of 7.8 ± 0.9 ng m−3.

A fast and reliable method for quantitative determination of total mercury in vegetables

A cloud-point extraction (CPE) process using the nonionic surfactant, polyethylene glycol tert octylphenyl ether (Triton X-114) was employed for determination of Hg(II) ions in aqueous solutions. The method is based on the ion-pairing reaction of Hg(II) with Pyronin B (PyrB+) in the presence of excess iodide at pH 6.0 and extraction of the complex formed. The chemical variables affecting CPE efficiency were studied, and the analytical characteristics of the method were obtained. The calibration curves were linear in the range of 1–40 μg L−1 with the detection limits of 0.35 and 0.30 μg L−1 at 556 and 521 nm. Selectivity was also tested. The coefficients of variation of the method are 2.4% and 5.2% for five replicate measurements of mercury at levels of 10 and 25 μg L−1, respectively. The results obtained for two certified reference samples were in a good agreement with the certified values. The method was applied to the determination of total mercury in vegetable samples.

Determination of total mercury in bauxite and bauxite residue by flow injection cold vapour atomic absorption spectrometry

A simple method for precise and accurate determination of total mercury in bauxite and bauxite residue was developed by using the flow injection mercury system. Samples of the solid materials were first microwave digested in acidic and oxidising conditions to convert all mercury to an aqueous ionic form. Following filtration and dilution, ionic mercury was reduced to elemental mercury with acidic SnCl2 to produce a cold mercury vapour. The mercury absorbance calibration graph was linear up to 20μg·kg−1 with R2>0.999. The detection limits were determined to be 23ng·kg−1 and 17ng·kg−1 for bauxite and bauxite residue respectively. The relative standard deviation for 1μg·L−1 mercury standard solution (n=27) was 1.5%. In the absence of a certified bauxite reference material, accuracy of the method was tested with the closest available zinc concentrate reference material. Spiking known amounts of mercury in bauxite and bauxite residue samples was also tested; 95–111% recovery was obtained for both samples. The method developed in this paper is recommended for measuring total mercury in bauxite and bauxite residue.

Quick and Direct Determination of Total Mercury in Soil Samples Using Portable Mercury Analyzer

The total mercury in soil was determined directly by Thermal decomposition-Cold vapor atomic absorption spectrometric method, which was used by portable mercury analyzer. The uniform samples without drying and digestion could be measured directly. The performance indicators of established method were satisfied in linear range, accuracy and precision. The limit of detection could approach to be as low as 1 μg/kg. Compared to the other methods to measure soil samples, the aforementioned method could achieve the similar results. The analyzer is portable and could measure the mercury in soil easily and quickly without using any reagents.

Preconcentration of Total Mercury from River Water by Anion Exchange Mechanism

A simple and cheap analytical technique was developed for the measurement of total mercury in river water samples using inductively coupled plasma-mass spectrometry (ICP-MS). It is based on the direct complexation of mercury ions using iodide and a cationic surfactant in water for its subsequent solid-phase extraction. Mercury ions are retained on the silica phase as ion pairs in the presence of iodide ions and dodecyltrimethylammonium bromide. Parameters having influential influence on the retention of Hg(II) were investigated: sample flowrate, eluent type, sample volume, iodide and surfactant concentrations. The retained mercury ions are stripped off from silica phase using 10 mL of 8 mol L(-1) HNO3 and quantified by ICP-MS. An enrichment factor of 50 was achieved with a maximum adsorption capacity of 718 μg Hg(II) g(-1). The limit of detection of Hg(II) was 8 pg mL(-1). The developed method was applied for the determination of total mercury in river and tap-water samples.

Determination of total mercury in biological tissue by isotope dilution ICPMS after UV photochemical vapor generation

A method is developed for the determination of trace mercury in biological samples using photo chemical vapor generation (PVG) and isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS) detection. Biological tissues were solubilized in formic acid. Subsequently, the sample solutions were exposed to an ultraviolet (UV) source for the reduction of mercury into vapor species prior to ICPMS measurements. The formic acid served not only as a tissue solubilizer in the sample preparation procedure, but also as a photochemical reductant for mercury in the PVG process. The problem arising from the opaque formic acid digested solution was efficiently solved by using ID method. The optimum conditions for sample treatment and PVG were investigated. A limit of detection (LOD) of 0.5 pg g(-1), based on an external calibration, provided 350-fold improvement over that obtained by utilizing conventional pneumatic nebulization sample introduction. Method validation was demonstrated by the determination of total mercury in several biological tissue certified reference materials (CRMs). The results were in good agreement with the certified values.

New method for mercury determination in microwave digested soil samples based on cold vapor capacitively coupled plasma microtorch optical emission spectrometry: Comparison with atomic fluorescence spectrometry

Abstract A new sensitive method for total mercury determination in digested soils using a miniaturized analytical system based on cold vapor capacitively coupled plasma microtorch optical emission spectrometry was developed and compared with cold vapor atomic fluorescence spectrometry as the standardized method. The soil samples were subjected to microwave digestion in aqua regia, than Hg cold vapor were chemically generated with SnCl2 and introduced via a 150 ml min− 1 Ar flow rate in the plasma microtorch operated at 10 W power level. The optical emission signal at 253.652 nm was measured with a commercially available microspectrometer. The method detection limit was 4.8 μg kg− 1 Hg, similar to that obtained in the standardized reference method. The precision of Hg determination over the concentration range of 0.27–55 mg kg− 1 was 0.8–7.7%. Analysis of six CRMs revealed a recovery of 97 ± 7% similar to 97 ± 9% found in the method based on cold vapor atomic fluorescence spectrometry. The Bland and Altman test carried out on 31 test soil samples showed no significant statistical difference between the results obtained by the proposed method and that taken as reference. The investigated analytical system can be prototyped as an alternative for the commercially existing atomic fluorescence spectrometry instrumentation. The benefits of the system are related to small size instrumentation and low analysis cost due to the low power and low Ar consumption for plasma generation.

Mercury in Coal – Determination of Total Mercury in Steam Coals by Cold Vapor Atomic Absorption Spectrometry (Cv-Aas)

Streszczenie Rtęć należy do najgroźniejszych globalnych zanieczyszczeń środowiska, nie jest biodegradowalna, a każdą z jej form należy uznać za toksyczną. Głównym źródłem antropogenicznej emisji rtęci i jej związków jest spalanie paliw stałych, dlatego bardzo ważne jest monitorowanie w nich poziomu jej stężenia. W artykule przedstawiono procedurę oznaczania rtęci całkowitej w próbkach węgli energetycznych dos­tarczonych do analiz przez Tauron Wytwarzanie S.A. Zbadano 17 próbek węgli kamiennych pochodzących z 13 polskich kopalń, zlokalizowanych głównie na terenie Górnośląskiego Zagłębia Węglowego (GZW). Węgle kamienne wzbogacono metodami klasycznymi w separatorach cieczy ciężkiej, osadzarkach, cyklonach cieczy ciężkiej, separatorach zwojowych osadzarkach, cyklonach cieczy ciężkiej, separatorach zwojowych oraz za pomocą flotacji. Próbki analityczne węgli kamiennych przygotowano według polskiej normy PN-90/G-04502, obejmującej ich suszenie, rozdrabnianie, mieszanie, pomniejszanie i podział. Oznaczanie rtęci całkowitej przeprowadzono na próbkach analitycznych o uziarnieniu 0,2 mm. Węgle kamienne poddawano termalnemu rozkładowi w temperaturze 850°C w suchym, oczyszczonym na filtrze z węgla aktywnego powietrzu (0,5 l/min). Zawarta w węglach kamiennych rtęć dzięki katalizatorowi CuO ulegała atomizacji do par Hg0, które analizowano analizatorem rtęci MA-2000 Nippon Instruments Corporation (zakres pomiarowy 0-1000 ng, granica detekcji 0,002 ng), metodą atomowej spektrometrii absorpcyjnej z techniką zimnych par (CV-AAS). Najważniejszymi zaletami urządzenia jest możliwość pominięcia etapu mineralizacji próbki oraz sprzężenie MA-2000 z automatycznym podajnikiem próbek SC-3, co redukuje czas pojedynczego pomiaru do 7 minut. Kalibrację aparatury wykonano stosując metodę krzywej wzorcowej, przyjmując za typ regresji wielomian trzeciego stopnia. Poprawność procedury pomiarowej sprawdzono używając standardowych materiałów odniesienia SRM-2693 i SRM-2692c. Wyniki badań wskazują na zawartość rtęci całkowitej w węglach kamiennych na poziomie 70,3-276,4 ppb. Metoda oznaczania rtęci całkowitej charakteryzuje się dobrą precyzją, względne odchylenie standardowe RSD wynosi 2-10%.

Voltammetric method for ultra-trace determination of total mercury and toxic metals in vegetables. Comparison with spectroscopy

Abstract A new procedure for the determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) traces in food matrices by square wave anodic stripping voltammetry and standard addition method is proposed. A rapid, inexpensive and multi-analyte analytical method suitable for food safety control is provided. Comestible vegetables were chosen as samples. A two-step, sequential determination was defined, employing two working electrodes: a gold electrode (GE) for mercury(II) and copper(II), and subsequently a hanging mercury drop electrode (HMDE) for copper(II), lead(II), cadmium(II) and zinc(II). No sample pre-treatment was needed. Spinach leaves, tomato leaves and apple leaves were employed as standard reference materials to optimize and defined the analytical procedure. The new method shows good selectivity, sensitivity, detectability and accuracy. A critical comparison with spectroscopic measurements is discussed. Spinach, lettuce and tomato samples sold on the market were analysed as real samples. Lead(II) and cadmium(II) concentration exceeded the relevant legal limits.

Mercury species determination by task specific ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction combined with cold vapour generation atomic absorption spectrometry

Task specific ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction (TSIL USA DLLME) combined with cold vapour atomic absorption spectrometry (CV AAS) for determination of mercury species in water and biological samples was developed. The proposed procedure was free of volatile organic solvents, and there was no need to use any dispersive solvents and complexing agents, in contrast to standard DLLME. Analytical signals were obtained without the back-extraction of the mercury species from the TSIL phase into an aqueous phase prior to their determination by CV AAS. The reducing agent Sn2+ could reduce Hg2+ and CH3Hg+ for determination of total mercury. Some essential parameters of the microextraction and cold vapour generation, such as the pH of sample solution, volume of the ionic liquid, ultrasonication time, cooling time, centrifugation time, matrix interferences and salt effect have been studied. Under optimal conditions, high extraction efficiency was achieved for the extraction of 1.0ngmL−1 of Hg2+ and 5ngmL−1 CH3Hg+ in 10.0mL of water solution employing 30μL of methyltrioctylammonium thiosalicylate as the extraction solvent. The enrichment factor for the method was 310 for Hg2+ and 200 for CH3Hg+. The detection limits were 0.03ngmL−1 for Hg2+ and 0.4ngmL−1 for CH3Hg+ respectively. The accuracy of the proposed method was evaluated by analysis of the Certified Reference Materials (NRCC DOLT-2, NIST 1643e). The method was applied to analysis of the tap, river, lake and sea water samples. The recoveries for reference materials and spiked samples were in the range of 95-103%.

Comparison of two different analytical procedures for determination of total mercury in wet deposition samples

Comparison studies have been performed on determination of total mercury in wet deposition by two analytical methods. The studies were carried out in the period of March to November 2009 at the sampling point located near intensive traffic in Southern Poland (Zabrze). The difference between these two methods consisted in preparation of samples for analysis and in the type of measuring device. In both cases, the method of cold vapour atomic absorption spectrometry (CV-AAS) after reduction of SnCl2 was used by means of a mercury analyzer model MA-2 produced by Nippon Instruments Corp. or of a mercury analyzer RA-915+ produced by LUMEX. Good agreement of the results have been obtained (relative error of the determination between the methods varied from 18% to 40%). Both analytical methods can be considered equivalent and used as a reference to each other. Quantity assessment of mercury wet deposition in southern Poland is lower than in 90 s, but still much higher in comparison with other countries in Europe and worldwide (ca. 30 μg·m –2 ·year –1 .

Determination of Total Mercury in Fish from Amur and Ussuri River of China by Microwave Digestion-ICP/MS Method

Determination of Total Mercury in Fish from Amur and Ussuri River of China by Microwave Digestion-ICP/MS Method

Mercury accumulation in adolescents scalp hair and fish consumption: a case study comparing populations having natural or anthropogenic sources

The consumption of fish is usually considered the main route of contamination of mercury in humans. In a climate change scenario implying ocean acidification, mercury methylation is expected to increase leading to bioaccumulation increments in the food chain, affecting mainly coastal populations.In this study, mercury accumulation and fish consumption was evaluated considering mercury concentrations in human scalp hair in relation to fish consumption habits in adolescents (16 to 21 years old) from two coastal areas: Angra do Heroismo and Aveiro (respectively a city in the Azores islands, and a mainland portuguese coastal city), presenting similar mercury levels in the surrounding coastal environments (0.1-0.3 μg g -1 in surface fine sediments) in spite of the mercury source (being from natural causes in the first site and anthropogenic in the second).Total mercury (THg) determination was performed by atomic absorption spectrometry with the Advanced Mercury Analyzer (AMA-254, LECO), and the analytical quality of the procedure was checked using reference materials TORT-2.The surveyed young populations showed similar fish consumption habits (0 to 6 meals in a week schedule) and revealed mercury concentrations in scalp hair ranging from 0.79 to 1.82μg g -1 . In spite of being young population consumers, results show a pattern of increased mercury concentration with increasing fish consumption habits.

Trace determination of total mercury in rice by conventional inductively coupled plasma mass spectrometry

Mercury is a potent neurotoxin with which food and beverages may be contaminated from a number of sources, both natural and anthropogenic. The determination of mercury at concentrations close to instrumental detection limits suffers from problems related to memory effects and loss, both during sample preparation and within sample introduction systems. L-cysteine (1%) was added to rice samples, standards, and rinse solutions in order to keep the mercury in solution and decrease the memory effect. Gold (1 μg L−1) was added online as an internal standard to improve accuracy and precision, while further decreasing the memory effect. A comparison of methods involving microwave digestion or acid extraction showed that both were capable of detecting single-digit μg kg−1 concentrations of mercury in rice. The microwave digestion ICP-MS procedure was further validated by a comparison of results with those obtained with a solid-sampling mercury analyser, based on CV-AAS, for which no significant differences were found. Both instrumental techniques were also validated by recoveries of spikes at various stages of the procedures and by the analysis of rice flour CRMs (NIST SRM 1568a and NIST SRM 1568, containing 5.8 μg kg−1 Hg and 6.0 μg kg−1, respectively). Recoveries between 80 and 120% were obtained and the concentrations measured in the CRM 1568a were not significantly different from the certified value.

Intake of predatory fish in Amazonia is a driver of toxicological risk for susceptible exposure groups

High fish intake has marked the scenario of riparian communities in Amazon basin during the last three decades. Although efforts have been done by some national and international scientific groups to control mercury exposure in Brazilian Amazon, the problem persists. The return of artisan gold mining, the new hydroelectric power plants (with its reservoirs) and the expansion of the agribusiness are some of the economic activities that may contribute to the increment of mercury load in the Amazon ecosystem with direct influence in the food chain. These changes in Amazon scenario increase complexity of environmental issue and mercury may become a threat for susceptible exposure groups. This study evaluated mercury exposure scenarios for susceptible groups around the hydroelectric plant to calculate toxicological risk before damming. During the period of 2009 to 2011, about 771 children under 16 years age and 276 female in reproductive age (from 16 to 40 years old) were assessed. Besides, regular fish samples (n=1580) were collected for total mercury determination. The mercury concentration in fish ranged from 0.01 to 6.06 mg/kg. For the current scenario the toxicological risk ranged from 3.5 to 24 for mercury for the susceptible groups. Regarding the critical scenario after 3 years flooding, the area is expected to double the risk for the same group, especially for the communities downstream, which may represent a critical situation.

A simple extraction procedure for determination of total mercury in crude oil

The determination of mercury in crude oil and petroleum products is particularly difficult due to the volatile nature of both mercury and the matrix, which may lead to significant loss of the analyte. A simple extraction method for total mercury has been developed to determine total mercury in crude oil using cold vapor atomic fluorescence spectrometry. The homogenized crude oil sample was diluted to 5, 10, and 20 % (w/w) in toluene. The diluted crude oil samples were spiked with 10 and 40 μg/kg (w/w). The samples were extracted using an oxidant/acid solution, BrCl/HCl. The mercury was extracted into the aqueous phase; the ionic mercury was then reduced to volatile elemental mercury (Hg(0)) by stannous chloride (SnCl2). The mercury vapor was detected by Merlin cold vapor atomic fluorescence spectrometry at a 253.7-nm wavelength. The average recoveries for mercury in spiked diluted crude oil (10 and 40 μg/kg, w/w) were between 96 and 103 %, respectively, in 5 and 10 % spiked diluted crude oil. Whereas, low recoveries (<50 %) were recorded in 20 % diluted spiked crude oil. The method detection limit was calculated as t (0.01)(n - 1) × SD where t is the student's value for 99 % confidence level and standard deviation estimate with n - 1 degrees of freedom. The method detection limit was found to be 0.38 μg/kg based on 5 g of diluted crude oil sample. The method is sensitive enough to determine low levels of mercury in crude oil.