Analysis of mercury

Baker RF, Blanchfield PJ, Paterson MJ, Flett RJ, Wesson L. 2004. Evaluation of non-lethal methods for the analysis of mercury in fish tissue. Trans Am Fish Soc 133 568-576. 

In many applications, such as the analysis of mercury in open ocean seawater, where the mercury concentrations can be as small as 10 ng/1 [468,472-476], a preconcentration stage is generally necessary. A preliminary concentration step may separate mercury from interfering substances, and the lowered detection limits attained are most desirable when sample quantity is limited. Concentration of mercury prior to measurement has been commonly achieved either by amalgamation on a noble-metal metal [460,467, 469,472], or by dithizone extraction [462,472,475] or extraction with sodium diethyldithiocarbamate [475]. Preconcentration and separation of mercury has also been accomplished using a cold trap at the temperature of liquid nitrogen. 

Analysis of mercury is difficult and specialized sampling and instrumental techniques are generally required to carry out an accurate analysis. Although atomic absorption is applicable, it requires specialized heating of the sample such as using a graphite furnace and other specialized sample handling [15-17],... 

Here, it is assumed that the permeability of a lattice is completely determined by the properties of bonds, for example, in a lattice of pores it is determined by the effective sizes of windows rw only, whereas the sizes of all sites (cavities) more than rw do not influence permeability. Let us illustrate the ideology of this approach using an example of the analysis of mercury intmsion in MP. For simplification, it is assumed that the whole volume of porous space is concentrated in the cavities (sites), and the windows (bonds) are only 2D cross sections with effective sizes of rWr... 

This second case study concerns the analysis of mercury in gaseous streams, particularly natural gas. Initially, analyses were to be carried out in the laboratory, but the final... 

There are many techniques used for the analysis of mercury in natural gas the most commonly used approach is the Jerome Analyzer (Arizona Instrument. Phoenix. Arizona. USA). This collects mercury onto a gold adsorber over a period of time by amalgamation. The 431 -X Mercury Vapour Analyzer is shown in Fig. 3.9. 

Fig. 3.10 The Sir Galahad System designed for the analysis of mercury vapour in gaseous streams.

The Sir Galahad instrument takes advantage of the inherent sensitivity of the Merhn fluorescence detector. This detector was originally developed for the analysis of mercury in environmental samples and its principles have been described by Godden and Stockwell [14], Stockwell et al. [IS] have described specific apphcations of the device. It offers a more hnear dynamic range, sensitivity, simplicity of design and the benefits of fiiU automation. 

Godden and Stockwell [11] have described a specific fluorescence detection system to provide fully supported analytical systems for routine analysis of mercury at low levels. The fluorescence approach provides a wide linear dynamic range and extremely low detection limits. P.S. Analytical s Merlin Plus System provides a fuUy automated system which will produce results at a rate of around 40 per hour. This is due to the optimization of the optical design of the detector, coupled to the inherent features of the fluorescence technique. 

This slide shows an example taken from an European standard for the analysis of mercury in water. For drinking water the standard states a reproducibility variation coefficient of 30% on a mercury concentration level of 0.8 pg/l. Provided that we can prove that we can perform as described in the standard our expanded measurement uncertainty (95% confidence) is estimated to 60%. 

Modified Electrodes A carbon paste electrode modified with zinc diethyldithiocarbamate was used for selective accumulation and stripping analysis of mercury(II) [477]. 

Figure 6.6. Cause-and-effect diagram for the analysis of mercury in fish showing the introduction of factors associated with the digestion process.

Analysis of Mercurial Matters.—Already a short description of the method of analysis pursued in determining the richness of mercurial ores has been given, and although the system of analysis to which reference will now be made is analogous te that described, still, since it is more applicable to mercurial compounds in general, it deserves a short space here. It is known as Millon s method, and is conducted as follows —... 

Figure 21-1 also illustrates an atomic fluorescence experiment. Atoms in the flame are irradiated by a laser to promote them to an excited electronic state from which they can fluoresce to return to the ground state. Figure 21-4 shows atomic fluorescence from 2 ppb of lead in tap water. Atomic fluorescence is potentially a thousand times more sensitive than atomic absorption, but equipment for atomic fluorescence is not common. An important example of atomic fluorescence is in the analysis of mercury (Box 21-1). 

In 1953, Billings et al. (17) studied the water vapor reaction with a lssHg source. The experiments were carried out in a flow system with nitrogen as carrier gas. The mercury oxide formed was found to be enriched in mHg, relative to its natural abundance. Similarly, with a -"-Hg lam)), an enriclnnent in 2,2Hg was observed (18). The isotopic analysis of mercury product in these studies was made by interferometry. 

S. Pirvutoiu, I. Surugiu, E.S. Dey, A. Ciucu, V. Magearu and B. Daniels-son, Flow injection analysis of mercury (II) based on enzyme inhibition and thermometric detection, Analyst, 126 (2001) 1612-1616. 

Jitaru, P. and F.C. Adams. 2004. Speciation analysis of mercury by solid-phase microextraction and multicapillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight-mass spectrometry. J. Chromatogr. A 1055 197-207. 

OSPAR. 1997. JAMP guidelines for the sampling and analysis of mercury in air and precipitation. London. 

W. Holak, Analysis of mercury-containing drugs by HPLC with atomic absorption detection, J. Liquid Chromatogr., 5 73 (1985). 

C. Gerbersmann, M. Heisterkamp, F. C. Adams, J. A. C. Broekaert, Two methods for the speciation analysis of mercury in t>sh involving microwave-assisted digestion and gas chromatography-atomic emission spectrometry, Anal. Chim. Acta, 350 (1997), 273 D285. 

D. C. Wigfield, S. A. Eatock, The matrix effect in the cold-vapor atomic absorption analysis of mercury in various biological tissues, J. Anal. Toxicol., 11 (1987), 137-139. 

L. N. Liang, G. B. Jiang, J. G. Liu, J. T. Hu, Speciation analysis of mercury in seafood by using high-performance liquid chromatography on-line coupled with cold-vapor atomic fluorescence spectrometry via a post column microwave digestion, Anal. Chim. Acta, Ml (2003), 131-137. 

The first systematic structure analysis of mercury oxosalts, salts containing oxygen atoms that are not part of an acid residue, was recently published. Structural description in terms of oxocentered [OHg4] tetrahedra with nonequivalent Hg bonds linked by both vertices and edges efficiently illustrated the unique structures and interrelationships of these compounds. 

Leg rand M, Lam R, Passes CJ, et al. Analysis of mercury in sequential micrometer segments of single hair strands offish-eaters 2007 41 (2) 593-8. 

A cold-trap pre-concentration procedure, which is incorporated into a standard jlameless atomic absorption analysis of mercury in environmental samples, has been used for both shipboard and laboratory analyses of mercury in seawater, The coefficient of variation for seawater containing 25 ng Hg/l, is 15%, and a detection limit of approximately 0,2 ng Hg is attainable. In surface seawaters of coastal and open regions of the northwest Atlantic Ocean mercury concentrations appear to decrease with increasing distance from terrestrial sources. In the open ocean samples they are less than 10 ng/l. and rather uniformly distributed. The amounts of mercury in inshore samples can approach 50 ng/l, A significant mercury fraction characterized by a stable association with organic material may be present in coastal waters. 

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. 

Lasora BK, Cittemam. 1991. Segmental analysis of mercury in hair in 80 women of Nome, Alaska. 

Marquez M, Silva M, Perez-Bendito D. 1988. Semi-automatic analysis of mercury in pharmaceuticals by catalytic titration. J Pharm Biomed Anal 6(3) 307-312. 

Yan D, Zhang J, Schwedt G. 1989. [Ion-chromatographic trace analysis of mercury, cadmium, and zinc by post-column derivatization with a water-soluble porphyrin.] Fresenius Z Anal Chem 334(6) 507-510. 

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