Neutron activation analysis mercury determination

Kosta and Byrne [42] used neutron activation analysis to determine down to 1 ng/g of mercury in 0.59 samples of flour. 

To date, a few methods have been proposed for direct determination of trace iodide in seawater. The first involved the use of neutron activation analysis (NAA) [86], where iodide in seawater was concentrated by strongly basic anion-exchange column, eluted by sodium nitrate, and precipitated as palladium iodide. The second involved the use of automated electrochemical procedures [90] iodide was electrochemically oxidised to iodine and was concentrated on a carbon wool electrode. After removal of interference ions, the iodine was eluted with ascorbic acid and was determined by a polished Ag3SI electrode. The third method involved the use of cathodic stripping square wave voltammetry [92] (See Sect. 2.16.3). Iodine reacts with mercury in a one-electron process, and the sensitivity is increased remarkably by the addition of Triton X. The three methods have detection limits of 0.7 (250 ml seawater), 0.1 (50 ml), and 0.02 pg/l (10 ml), respectively, and could be applied to almost all the samples. However, NAA is not generally employed. The second electrochemical method uses an automated system but is a special apparatus just for determination of iodide. The first and third methods are time-consuming. 

Stiller et al. [824] have described the determination of cobalt, copper, and mercury in Dead Sea water by neutron activation analysis followed by X-ray spectrometry and magnetic deflection of /i-ray interference. 

Procedures for the determination of 11 elements in coal—Sb, As, Br, Cd, Cs, Ga, Hg, Rb, Se, U, and Zn—by neutron activation analysis with radiochemical separation are summarized. Separation techniques include direct combustion, distillation, precipitation, ion exchange, and solvent extraction. The evaluation of the radiochemical neutron activation analysis for the determination of mercury in coal used by the Bureau of Mines in its mercury round-robin program is discussed. Neutron activation analysis has played an important role in recent programs to evaluate and test analysis methods and to develop standards for trace elements in coal carried out by the National Bureau of Standards and the Environmental Protection Agency. 

Mass balance measurements for 41 elements have been made around the Thomas A. Allen Steam Plant in Memphis, Tenn. For one of the three independent cyclone boilers at the plant, the concentration and flow rates of each element were determined for coal, slag tank effluent, fly ash in the precipitator inlet and outlet (collected isokinetically), and fly ash in the stack gases (collected isokinetically). Measurements by neutron activation analysis, spark source mass spectroscopy (with isotope dilution for some elements), and atomic adsorption spectroscopy yielded an approximate balance (closure to within 30% or less) for many elements. Exceptions were those elements such as mercury, which form volatile compounds. For most elements in the fly ash, the newly installed electrostatic precipitator was extremely efficient. 

Analysis of the samples for elemental constituents was performed using instrumented neutron activation analysis (NAA) and spark source mass spectrometry (SSMS) (2). In addition, the many mercury determinations were made by flameless atomic absorption (AA). 

Voltammetric methods have been used to determine mercury in soil composts. The amount of mercury leaching from composts was very low [158]. Neutron activation analysis has been used to determine mercury in soil [159]. 

Although most of the elements have been determined by XRF (21), some other methods were used. The fluorometric method for selenium uses diaminonaphthalene (32). The colorimetric method for molybdenum uses potassium thiocyanate (33). The uranium analyses were done by delayed neutron activation analysis (34). For the XRF analyses of the oil and water, a blank value implies that there were no x-rays above background for that element. Two elements conspicuously missing from Table IV are cadmium and mercury. Preliminary analyses for these two elements have not yielded reproducible results. Further work is needed before we can make definitive statements about cadmium and mercury. 

Many researchers have attempted to determine mercury levels in the blood, urine, tissues, and hair of humans and animals. Most methods have used atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), or neutron activation analysis (NAA). In addition, methods based on mass spectrometry (MS), spectrophotometry, and anodic stripping voltametry (ASV) have also been tested. Of the available methods, cold vapor (CV) AAS is the most widely used. In most methods, mercury in the sample is reduced to the elemental state. Some methods require predigestion of the sample prior to reduction. At all phases of sample preparation and analysis, the possibility of contamination from mercury found naturally in the environment must be considered. Rigorous standards to prevent mercury contamination must be followed. Table 6-1 presents details of selected methods used to determine mercury in biological samples. Methods have been developed for the analysis of mercury in breath samples. These are based on AAS with either flameless (NIOSH 1994) or cold vapor release of the sample to the detection chamber (Rathje et al. 1974). Flameless AAS is the NIOSH-recommended method of determining levels of mercury in expired air (NIOSH 1994). No other current methods for analyzing breath were located. 

Itawi RK, Subramaniau S, Turec. 1990. Determination of selenium, cadmium and mercury in an aquatic environment of Bombay by sub-stoichiometric neutron-activation analysis. J Radioanal Nucl Chem 138(l) 63-66. 

Zhuang G, Wang Y, Zhi M, et al. 1989. Determination of arsenic, cadmium, mercury, copper and zinc in biological samples by radiochemical neutron-activation analysis. J Radioanal Nucl Chem 129(2) 459-464. 

Other Metal-Peptide and -Protein Interactions.—The determination of protein-bound trace elements in biological material by neutron activation analysis has been described Zn, Hg, Cu, and Se were accurately detected in human liver samples, provided that most of the element concerned was protein bound. An interaction of mercury with a protein or a protein-DNA complex has been invoked to explain the partitioning of the metal in euchromatin over heterochromatin (from mouse liver nuclei) by a 10 1 ratio. " Bovine retinas, isolated rod outer segments and emul-phogene extracts of rod outer segments have been shown to contain appreciable amounts of Zn ", Ca and the zinc levels being light sensitive. 

As identified in Table 1, the most common methods used to determine mercury levels in blood, urine, and hair of humans and animals include atomic absorption spectrometry (A AS), neutron activation analysis (NAA), x-ray fluorescence (XRF), and gas chromatography (GC). 

The Trace Metals Project conducted a study to identify the type of container which would provide minimum losses of arsenic and mercury by precipitation, volatilization, adsorption, or diffusion. Solutions of organomercury and organoarsenic compounds added to petroleum feedstock were used. Because of the relative ease with which mercury and arsenic can be determined at sub-parts-per-million levels in a hydrocarbon matrix by instrumental neutron activation analysis (INAA), this technique was used for the analytical measurements. The solutions were stored in five different types of glass and/or plastic containers and sampled periodically over eight months (12). The results of the study are summarized in Tables 2.III and 2.IV. 

Earlier methods used to determine mercury in biological tissue and fluids were mainly colorimetric, using dithizone as the com-plexing agent. However, during the past two to three decades, AAS methods - predominantly the cold vapor principle with atomic absorption or atomic fluorescence detection - have become widely used due to their simplicity, sensitivity, and relatively low price. Neutron activation analysis (NAA), either in the instrumental or radiochemical mode, is still frequently used where nuclear reactors are available. Inductively coupled plasma mass spectrometry (ICP-MS) has become a valuable tool in mercury speciation. Gas and liquid chromatography, coupled with various detectors have also gained much importance for separa-tion/detection of mercury compounds (Table 17.1). 

A78. Nadkarni, R.A. and B.C. Haidar Substoichiometric determination of mercury by neutron activation analysis J. Radioanal. Chem. 10 (1972) 181-186. 

Versieck, J. Vanballenberghe, L. and De Kesel, A. (1990). Determination of mercury in human serum by neutron activation analysis. Biol. Trace Element Res. 26-27,683. 

Bayat, I., Raufi, N.D. and Nejat, M.(1985) Determination of mercury and other toxic elements in fish and foodstuffs using destructive neutron activation analysis. In Health-related monitoring of trace element pollutants using nuclear techniques. A technical document issued by the international atomic energy agency, Vienna. IAEA-TECDOC-330 141-146. 

Filby, R.H., Davis, A.I., Shah, K.R. and Haller, W.A. (1970) Determination of mercury in biological and environmental materials by instrumental neutron activation analysis. Microchim. Acta, 1970, 1130-1136. 

Greenberg, R.R. (1980) Simultaneous determination of mercury and cadmium in biological materials by radiochemical neutron activation analysis. Anal. Chem., 52, 676-679. 

Henke, G., Westerboer, S., and Potheine, H. (1968) Determination of mercury in blood, urine, and renal biopsy material by neutron-activation analysis. Arch. Tox., 23, 293-298. 

Kim. C.K. and Silverman. J. (1965) Determination of mercury in wheat and tobacco leaf by neutron activation analysis using mercury-197 and a simple exchange separation. Anal. Chem. 37.1616-1617. 

Pillay, K.K., Thomas, C.C., Sondel, J.A. and Hyche, C.M. (1971) Determination of mercury in biological and environmental samples by neutron activation analysis. Anal. Chem., 43, 1419-1425. 

Rottschafer, J.M., Jones, J.D., and Mark, H.B. (1971) A simple, rapid method for determining trace mercury in fish via neutron activation analysis. Environ. Sci. Technol., 5. 336-338. 

Determination of silver can be carried out by polarography in 0.1 M KNO3 electrolyte. A dropping mercury electrode is placed into the solution to be analyzed and by changing the charge on the electrode the Ag in solution will form an amalgam with the mercury at different potentials. Polarographic waves are produced from which the concentration of the silver can be obtained. Neutron activation analysis (NAA) is based on the formation of radioactive isotopes when a sample is irradiated by neutrons. NAA is not extensively used in routine analysis because costs are prohibitive, but there is a limited use in the field of biomedical research [37],... 

Westoo reported results obtained by gas chromatography with electron capture and with mass spectrometric detection on a range of samples of fish, (Table 17) Total mercury was also determined on these samples by neutron activation analysis. Results obtained by the three methods agree with 10% of the average value. 

That fallout of trace elements from atmospheric pollution is widespread and far from confined to urban and industrial areas, is also borne out by data published by the UK Atomic Energy Authority, who determined, by neutron activation analysis, about 30 trace elements in airborne dust, rainwater and dry deposition, sampled at regular intervals in north-west England [188]. The highest concentrations measured in air were for chlorine, sodium, calcium, aluminium, iron, lead and zinc, and there were also measurable levels of antimony, arsenic and mercury, usually in the winter months, when there was a general increase in trace-element concentration. Further data were published on the atmospheric content and total deposition of a wide range of trace elements at seven non-urban sites (one in Shetland) in the UK in the years 1972 and 1973 [189]. Data have also been published for the North Sea and the Firth of Clyde [190]. 

At NBS, the neutron activation method with combustion separation step applied to the determination of mercury and selenium in coal has been modified and extended to analysis for arsenic, zinc, and cadmium by Orvini et al. (14). 

Pritchard, J.G. and Saied, S.O. (1986) Studies on the determination of mercury in human beard shavings by neutron-activation and gamma-ray analysis. Analyst, 111, 29-35. 

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