Mercury In Biological Materials Research Articles

Токсико-екологічний аналіз поводження з ртутьвмісними відходами в Україні

Relevance. The multifaceted intersectoral problem of human security in contact with mercury has gained global significance in the twentieth century, it is relevant today. Considerable attention is paid to the environmental and hygienic aspects of mercury hazards in the field related to the production and disposal of waste containing Hg. The Aim of the Research. Analyze the data of own research on mercury content in the environment in connection with the management of mercury-containing waste and justify a set of preventive environmental and hygienic, technological and organizational measures to improve safety, public health and improve the environment in the region and the country in general. Materials and Methods. Sampling, sample preparation and determination of mercury content in environmental facilities and bioassays were performed according to MI “Methodical instructions for the determination of mercury in biological material, air, drinking water, food products and the environment.” The concentration of mercury was measured by the method of AAS “cold steam” on the upgraded device “Yulia-2M”. The mercury content in soil and air at the spontaneous dump of mercury lamps in Odessa region, on the border of the sanitary protection zone and in the air of the working zone of the enterprise for utilization of mercury lamps was studied. For sample preparation, chemically pure nitric acid (56%) was used, to reduce mercury during the analysis of chemically pure tin (II) chloride. Results and Conclusions. Mercury lamps have been shown to be hazardous to the environment and human health without proper disposal. Mercury lamps should be collected and disposed of as hazardous waste not only in industrial facilities but also in the general public. The formation of spontaneous unauthorized landfills of mercury lamps is unacceptable. The problem of environmental monitoring needs to be addressed at the state level with the mandatory involvement of specialists in the field of hygiene, toxicology and analytical chemistry of heavy metals in cases of violations to assess the level of danger and make informed decisions on approaches to elimination of mercury sources. Key Words: mercury, mercury lamps, ecology.

Mercury speciation in environmental samples by cold vapour atomic absorption spectrometry with in situ preconcentration on a gold trap

A method has been developed for the determination of total and organic mercury in biological materials and sediments. A microwave assisted mineralization of the organic mercury, after its extraction from the matrix, is described. This procedure warrants complete transformation of Hg(II) and, consequently, the quantitative reduction to Hg(0). The conditions for mercury reduction were optimized by a central composite design. The preconcentration of the analyte has been achieved by amalgamation on a trap system, consisting in a pyrolytic graphite platform wound by a gold wire. Mercury was determined by cold vapour atomic absorption spectrometry. The method was validated by the analysis of two certified reference materials and applied to the determination of total and organic mercury species in mussel tissues and sediments. The method is simple and practical, and offers the advantage of not requiring special equipment to measure inorganic and organic mercury simultaneously.

Sequential quantification of methyl mercury in biological materials by selective reduction in the presence of mercury(II), using two gas–liquid separators

The present procedure is based on the sequential selective reduction of mercury(II) and methyl mercury using two gas–liquid separators in series. Cold vapor atomic absorption spectrometry was used for detection. Mercury(II) is reduced by a 0.01% m/v sodium tetrahydroborate solution and driven to the absorption cell in the first separator. The methyl mercury species is reduced by the same reductant but at a 0.3% m/v concentration, and in the presence of iron(III) chloride. Parameters such as argon flow rate, and the NaBH 4 and dithiophosphoric acid diacyl ester concentrations were optimized. At the optimized conditions, and using aqueous standards for calibration, the corresponding limits of detection (3σ b, n=10) were 400 and 600 ng l −1 for mercury(II) and methyl mercury, respectively. The sample throughput was 12 h −1. The procedure was used for the determination of methyl mercury in dogfish liver and dogfish muscle certified reference materials, and good concordance between found and certified values was observed.

Direct determination of methylmercury and inorganic mercury in biological materials by solid sampling-electrothermal vaporization-inductively coupled plasma-isotope dilution-mass spectrometry.

This paper reports on the use of solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry (SS-EIV-ICPMS) for the direct and simultaneous determination of methylmercury and inorganic mercury in biological materials. The main advantage of this fast and sensitive method is that no sample preparation is required. In this way, the sample throughput can be considerably increased, problems of contamination and analyte losses are kept to a minimum and, even more important, the original chemical form of the different analyte species in the solid samples is preserved. To achieve this goal, a solid sample is inserted into a graphite furnace of the boat-in-tube type and is subsequently submitted to an appropriate temperature program, leading to the separate vaporization of methylmercury and inorganic mercury, which are transported into the ICP by means of an argon carrier gas. The separation was accomplished within 75 s. For the quantification of the two peaks, species-unspecific isotope dilution was used. For this purpose, a stable flow of argon loaded with gaseous Hg isotopically enriched in 200Hg was generated using a permeation tube that was constructed in-house. Its emission rate was determined by collecting the mercury released during a given time interval on a gold-coated silica absorber, after which the amount collected was released by heating of the absorber and determined by cold vapor atomic absorption spectrometry (CVAAS) and cold vapor atomic fluorescence spectrometry (CVAFS). A reference material from the Canadian National Research Council (NRC) (TORT-2) was used to assess the accuracy of the method. For the application of the method to samples with diverse mercury contents, the spike/sample ratio can be optimized by varying the emission rate of the permeation tube simply by adapting its temperature. To prove the feasibility of this approach, two reference materials (BCR 463 and DORM-2) with a methylmercury content more than 10 times higher than that of TORT-2 were also analyzed. The detection limits obtained for 1 mg of sample (2 ng g(-1) and 6 ng g(-1) for methylmercury and inorganic mercury, respectively) were found to be sufficiently low for this kind of application and are competitive when compared to other techniques.

Determination of Total Mercury in Biological Materials by Cold Vapor Atomic Absorption Spectrometry after Microwave Digestion

The use of several acid mixtures for digestion of marine biological materials with microwave-assisted heating was investigated. The mixtures of HNO3–H2SO4–H2O2and of HNO3–H2SO4–HCl were most effective after microwave digestion, resulting in complete decomposition of samples. Recoveries of added mercury to marine biological tissues were satisfactory, ranging from 91 to 108%. This indicated that no matrix interference or loss of volatile mercury occurred during the analysis. The mercury content of standard reference materials after microwave digestion corresponded closely to the certified values.

On-line preconcentration and determination of mercury by flow injection inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) flow injection method for the determination of trace levels of mercury in biological materials is described based on complexation of the metal ion with 1,5-bis(di-2-pyridyl)methylene thiocarbonohydrazide (DPTH) and its subsequent on-line extraction into isobutyl methyl ketone (IBMK). The organic phase (containing the complex) is mixed on-line with SnCl2 in dimethylformamide. The optimum experimental conditions are evaluated for the continuous extraction of HgII, the direct generation of mercury vapour from the organic phase and the final determination of this element by ICP-AES. The detection limit for mercury is 0.002 µg ml–1 and the calibration is linear from 0.01 to 5 µg ml–1. The precision of the method (evaluated as the relative standard deviation obtained after analysing ten series of ten replicates) was ± 3.3% at the 0.25 µg ml–1 level of HgII. The effect of various inorganic ions and some organic masking substances on the determination of mercury by the proposed method is examined under the optimum working conditions. The tolerance limits found show that mercury can be determined in the presence of a variety of ions including most of those that commonly occur with mercury in natural samples.

Microwave dissolution for the determination of mercury in biological samples

Microwave dissolution in closed teflon vessels is described for the determination of ng g −1 contents of mercury in biological materials, prior to two-stage gold amalgamation and cold-vapour atomic absorption spectrometry. Six samples can be decomposed simultaneously within 20 min, with a preset heating programme. The detection limit is 0.84 ng g −1 for a 100-mg sample. Results for six certified reference materials agreed with the certified values.

Determination of mercury in biological materials by CV-AAS after wet digestion

The paper describes the determination of ultratrace concentrations of mercury in biological materials. Samples were digested in nitric acid under pressure in a polytetrafluoroethylene bomb. Mercury was determined in the digest solution by cold vapour atomic absorption spectrometry using stannous chloride reduction and two-stage gold amalgamation. The detection limit is 0.12 ng. Analysis of several certified reference materials yielded results in excellent agreement with the certified values. The results for blood serum of several subjects ranged from 0.2 to 0.8μg 1−1.

Determination of trace amounts of organic and inorganic mercury in biological materials by graphite furnace atomic absorption spectrometry and organic mercury speciation by gas chromatography.

A procedure for determination of both organic and inorganic mercury in biological materials by graphite furnace atomic absorption spectrometry (GFAAS) is described. Organic mercury is extracted as a chloride derivative by benzene and reextracted by a thiosulfate solution. Inorganic mercury is converted into a methyl chloride derivative by methanolic tetramethyltin prior to extraction. A 20-..mu..L aliquot of the thiosulfate solution is injected into the graphite furnace. The calibration is linear up to 12 ng of Hg/20 ..mu..L injected. The limit of detection of mercury is 0.04 ng of Hg/20 ..mu..L injected. The organic mercury thiosulfate extract was treated with CuCl/sub 2/, reextracted in the benzene layer, and analyzed by gas chromatography (GLC) for speciation.

Direct determination of inorganic mercury in biological materials after alkali digestion and amalgamation.

A reliable method is described for the determination of inorganic mercury in biological materials in the presence of organic mercury. This is principally based on the fact that hydrogen peroxide oxidatively liberates inorganic mercury from organic substances in strong alkali and reduces it to the metallic state without decomposing organic mercurials concomitantly present. The metallic mercury, vaporised with a nitrogen stream, is trapped by gold amalgamation and then released for electrothermal atomisation atomic-absorption spectrometry. The detection limit is 1 ng of inorganic mercury and the co-efficient of variation for 40 ng of inorganic mercury is 2.8%.

Studies on mercury pollution: microdetermination of mercury in biological materials by cold vapour atomic absorption spectrometry.

A simple, rapid, precise and accurate method for the determination of mercury in biological material is described. Biological samples were digested with nitric acid and acidified potassium permanganate and determined by cold vapour analyser. The proposed method was successfully employed for the determination of mercury in samples of fish, hair and blood.

Determination of trace concentrations of mercury in biological materials after digestion under pressure in nitric acid catalysed by vanadium pentoxide.

The determination of trace amounts of mercury in biological materials is described. Vanadium pentoxide-catalysed digestion in nitric acid under pressure in a PTFE autoclave was used for destruction of the samples. Satisfactory destruction was achieved in the absence of sulphuric acid. Mercury was determined in the digest solution by atomic-absorption spectrophotometry using a cold vapour circulating in a closed system The detection limit was optimally 1 ng g–1. No losses of mercury occurred. The accuracy of the determination was confirmed by the close agreement of certified and determined concentrations of mercury in reference materials.

Determination of arsenic and mercury in biological materials by neutron activation analysis.

Determination of arsenic and mercury in biological materials by neutron activation analysis.

Development and application of the cold-vapour techniques for the determination of mercury in biological materials--a review.

The development of the cold-vapour technique for the determination of mercury is reviewed, from the early methods by which mercury in a sample was converted into a vapour for absorption measurements, to the recent developments utilizing reduction of mercury to the elemental state with tin(II) chloride and its measurement with an atomic-absorption spectrophotometer. Application of the technique to the analysis of a number of materials is discussed, especially its increasing role in the estimation of environmental exposure. Interferences, including broad-band absorption, are considered, together with methods for compensation or elimination.

Trace determination of mercury in biological materials by flameless atomic absorption spectrometry

A new rapid wet-ashing procedure for biological material is described. The samples are boiled for 5–10 min in a mixture of nitric and hydrobromic acid under reflux. Mercury is then determined by the flameless cold-vapour, atomic absorption technique and complete release is shown to occur even when the fat present is not fully decomposed. The results are discussed with regard to the normal bromine and iodine content of marine samples. The enhancement obtained with bromine can easily be compensated by digesting the standards. Iodine, however, reduces the peak heights and the content of this element must be judged separately for samples other than fish, which can always be safely analysed without interference.

Method for determination of mercury in biological materials by neutron activation analysis.

Method for determination of mercury in biological materials by neutron activation analysis.

Determination of Submicro Quantities of Mercury in Biological Materials

Abstract A rapid digestion method for biological materials containing mercury is described. The results indicate that four mercuric compounds are recovered in 96 to 101% yield.

Determination of Mercury in Biological Materials

Abstract Mercury in biological samples is determined by digestion in nitric acid, sulfuric acid, and permanganate, followed by reduction and aeration for measurement by atomic absorption at room temperature. The average recovery is 95.8% with a standard deviation of 13.3%. The standard deviation, calculated from the difference between duplicates of 23 samples, is 0.063 μg mercury, which represents 9.4% of the average value of the samples. The method is simple and requires approximately 4 hr for completion. Mercury can be confirmed by adsorption on gold foil after maximum absorbance has been obtained during aeration.

A simple neutron activation method for mercury in biological material

A simple radiochemical neutron activation method based on 65 hr 197Hg is described. After decomposition of the irradiated samples with a HNO 3/H 2SO 4 mixture, mercury is isolated by sulphide precipitation at pH 8–9. The chemical yield is higher than 98 per cent. A number of elements accompany mercury in the separation, but in most biological samples, none of their radioisotopes interfere seriously in the determination if the mercury content is higher than 0·0.1 ppm.

Automated determination of traces of mercury in biological materials by substoichiometric radioisotope dilution

Solid samples (1–2 g) are burned in oxygen in a flask containing radiomercury in dilute hydrochloric acid, in which the non-active mercury to be determined is immediately absorbed. All mercury is subsequently extracted by dithizone in carbon tetrachloride and then re-extracted into dilute hydrochloric acid. This aqueous phase is further analysed automatically (AutoAnalyzer, 20 samples hr ) as previously described. Liquids (up to 100 ml) are analysed in the same way but instead of being burned in oxygen are first oxidized with potassium permanganate in acid medium. Quantities between 2 and 0.00004 ppm Hg were determined in various materials. Results for international biological standards agreed well with values obtained by activation analysis: kale 0.159 ppm Hg (relative standard deviation 2%) and IAEA cereals 0.0435 ppm Hg (± 5%). The new method is far more simple and rapid than activation analysis and just as sensitive; it is therefore more suitable for routine work. About 100 samples can be analysed per day.