Methylmercury determination

Batti et al. [68] determined methylmercury in river sediments from industrial and mining areas. 

Bartlett et al. [55] used the method of Uthe et al. [70] for determining methylmercury. Sediment samples of 2-5g were extracted with toluene after treatment with copper sulphate and an acidic solution of potassium bromide. Methylmercury was then back extracted into aqueous sodium thiosulphate. This was then treated with acidic potassium bromide and copper sulphate following which the methylmercury was extracted into pesticide grade... 

Both the Farris et al. (1993) and the Gray (1995) PBPK models address the kinetics of methylmercury in rats. Both models provide useful insights into important physiological processes determining methylmercury distribution and changes in tissue concentrations. Also, both studies suggest further work to... 

Two methods for determining methylmercury chloride in fish, egg-white, meat and liver without interference by thiols are described on the following pages. 

Kampe and McMahon used the Westoo procedure to determine methylmercury in fish. Their procedure involved the partitioning of methylmercury chloride in benzene and gas chromatographic analysis with electron capture detection. Down to 0.02ppm of methylmercury chloride can be detected in a lOg sample. 

Uthe et al 2 have described a rapid semi-micro method for determining methylmercury in fish and crustacean and aquatic mammal tissue. The procedure involves extracting the methylmercury into toluene as methylmercury bromide, partitioning the bromide into aqueous ethanol as the thiosulphate - complex, re-extracting... 

Experimental conditions to determine methylmercury and inorganic Hg in water samples by slurry sampling cold vapour atomic absorption spectrometry were determined by simplex (APDC concentration, agitation time, silica amount and agitation time), after an experimental design underlined their importance. 

Bushee has determined methylmercury at 870 fig 1 in a different fish reference material and thimerosol in contact lens solutions with good agreement with values reported previously [41]. Detection limits... 

Shipp AM, Gentry PR, Lawrence G, Van Landingham CF, Covington T, Clewell HJ, Gribben K, Crump K. 2000. Determination of a site-specific reference dose for methylmercury for fish-eating populations. Toxicol Ind Health 16 335 38. 

Chassaigne H, and Lobinski R (1998) Characterization of horse kidney metallothionein isoforms by electrospray MS and reversed-phase HPLC-electrospray MS. Analyst 123 2125- 2130. Chemosphere (1999) Special issue - Sources of error in methylmercury determination during sample preparation, derivatisation and detection. Chemosphere 39 1037-1224. 

Wise SA, Schantz MM, Poster DL, Lopez de Alda MJ, and Sander LC (2000) Standard reference materials for the determination of trace organic constituents in environmental samples. In Barcelo D, ed. Sample Handling and Trace Analysis of Pollutants Techniques, Applications and Quality Assurance, pp 649-687. Elsevier Science Publishers, Amsterdam, The Netherlands. Yoshinaga Y, Morita M, and Okamoto K (1997) New human hair certified reference material for methylmercury and trace elements. Fresenius J Anal Chem 357 279-283. 

Lansens, P., M. Leermakers, and W. Baeyens. 1991. Determination of methylmercury in hsh by headspace-gas chromatography with microwave-induced-plasma detection. Water Air Soil Pollut. 56 103-115. 

Kimura and Miller [29] have described a procedure for the determination of organomercury (methylmercury, ethylmercury and phenylmercury compounds) and inorganic mercury in soil. In this method the sample is digested in a steam bath with sulphuric acid (0.9M) containing hydroxy ammonium sulphate, sodium chloride and, if high concentrations of organic matter are present, potassium dichromate solution. Then, 50% hydrogen... 

Total mercury is determined in soils containing phenylmercury acetate and or ethylmercury acetate using the method described by Polley and Miller [31]. Total mercury is determined in soils containing methylmercury chloride and methylmercury dicyanamide by the method described by Kimura and Miller [32], Kimura and Miller [30] present chemical data on the nature of residual mercurials in soil and in the atmosphere surrounding the treated soil to further elucidate the phenomena of degradation in soil. 

Cappon and Crispin-Smith [59] have described a method for the extraction, clean-up and gas chromatographic determination of alkyl and aryl mercury compounds in sediments. The organomercury compounds are converted to their chloroderivatives and solvent extracted. Inorganic mercury is then isolated as methylmercury upon reaction with tetramethyltin. The initial extract is subjected to a thiosulphate clean-up and the organomercury species are isolated as their bromoderivatives. Total mercury recovery was in the range 75-90% and down to lpg kg-1 of specific compounds can be determined. 

A method [62] has been described for the determination of down to 2.5pg kg-1 alkylmercury compounds and inorganic mercury in river sediments. This method uses steam distillation to separate methylmercury in the distillate and inorganic mercury in the residue. The methylmercury is then determined by flameless atomic absorption spectrophotometry and the inorganic mercury by the same technique after wet digestion with nitric acid and potassium permanganate [63]. The well known adsorptive properties of clays for alkylmercury compounds does not cause a problem in the above method. The presence of humic acid in the sediment did not depress the recovery of alkylmercury compounds by more than 20%. In the presence of metallic sulphides in the sediment sample the recovery of alkylmercury compounds decreased when more than lmg of sulphur was present in the distillate. The addition of 4M hydrochloric acid, instead of 2M hydrochloric acid before distillation completely, eliminated this effect giving a recovery of 90-100%. 

This excellent method was sufficiently sensitive to determine 0.02mg kg-1 methylmercury and 9mg kg inorganic mercury in river sediment samples. 

Workers at the Department of the Environment, UK [47], have described a procedure for the determination of methylmercury compounds in soils and sediments which involves extraction with a carbon tetrachloride solution of dithizone, reduction to elemental mercury then analysis by atomic absorption spectrometry. 

Robert and Robenstein [66] carried out indirect determination of Hg119 NMR spectra of methylmercury complexes, e.g. CH Hg11 thiol ligands in sediment samples. 3... 

Fig. 13.8 Analysis of sterilized and unsterilized sediments from Hale Point, for methylmercury. Total mercury is 7.24 jg g 1. Results up to day 25 are the mean of eight determinations results beyond day 25 are the mean of four determinations. Error bars represent range limits for each analysis series. The samples were stored at room temperature (18°C), untreated o sterilized samples Source Reproduced with permission from McMillan Magazines [55]... 

The addition of anticoagulents and/or preservatives, a practice that may be tolerated for total element determination, should be avoided for two reasons. First, the compounds used are usually complexing agents. They therefore could bind various trace elements. Second, they could destroy some species. For example, the addition of potassium dichromate to urine in the presence of nitric acid could destroy methylmercury If the use of such compounds is unavoidable, then there should be experimental evidence to show that the speciation of the element imder study has not been adversely affected. 

S. Rio Segade and J. F. Tyson, Determination of methylmercury and inorganic mercury in water samples by slurry sampling cold vapor atomic absorption spectrometry in a flow injection system after preconcentration on silica C18 modified, Talanta, 71(4), 2007, 1696-1702. 

E. Ramalhosa, S. Rio Segade, E. Pereira, C. Vale and A. Duarte, Simple methodology for methylmercury and inorganic mercury determinations by high-performance liquid chromatography-cold vapour atomic fluorescence spectrometry. Anal. Chim. Acta, 448(1-2), 2001, 135-143. 

R. Puk and J. H. Weber, Determination of mercury (II), mono-methylmercury cation, dimethylmercury and diethylmercury by hydride generation, cryogenic trappling and atomic absorption spectrometric detection. Anal. Chim. Acta, 292(1-2), 1994, 175-183. 

A new procedure for determination of inhibitors (pesticides and methylmercury) based on extraction of the inhibitor by the enzyme... 

S. Han, M. Zhu, Z. Yuan and X. Li, A methylene blue-mediated enzyme electrode for the determination of trace mercury (II), mercury (I), methylmercury, and mercury-glutathione complex, Biosens. Bioelectr., 16 (2001) 9-16. 

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