Showing papers on "Organomercury Compounds published in 2000"

The speciation of mercury and organomercury compounds by using high-performance liquid chromatography

Abstract: No previous reviews on speciation analysis by high-performance liquid chromatography (HPLC) have dealt solely with the analysis of mercury. The analytical methods are classified on the basis of the sample matrix analysed and deal with: standards and water, marine organisms, biomedical samples and sediments. The relevant technical information, column type, mobile phase, method of detection and detection limit, is presented in tabular form for each of the sample types. The majority of methods use reversed phase chromatography, usually with a buffer, organic modifier and some form of counter ion or complexing agent. Other aspects addressed in this review include sample preparation and instrumental methods of analysis. The review covers publications from 1986 to 1999.

Analysis of amino acids and organometallic compounds by particle beam–hollow cathode glow discharge atomic emission spectrometry

Abstract: An evaluation of the particle beam–hollow cathode glow discharge atomic emission spectroscopy (PB-HC-AES) system as an element-specific detector for liquid chromatography is described for aromatic amino acids and organomercury and organolead compounds. A high-efficiency thermoconcentric nebulizer is used to introduce analyte particles into a heated hollow cathode glow discharge source for subsequent vaporization, atomization and excitation. Emission responses for hydrogen and nitrogen of amino acids in flow injection mode using 200 µL injection volumes indicate detection limits of 0.13 and 3.6 ppm elemental H and N, respectively, with RSD <10% for triplicate injections over a concentration range of 10−3–10−2 M. Analysis of the response of hydrogen and nitrogen emission signal intensities to differences in amino acid stoichiometries indicates the potential of the PB-HC-AES system for the determination of empirical formulas based on HI/NI intensity ratios. Detection limits for metals and non-metals in organomercury compounds as determined through flow injection of 200 µL sample volumes fall in the sub-ppm range. Liquid chromatographic separations of both amino acids and organolead compounds demonstrate the feasibility of the PB-HC-AES system as a detector for liquid chromatography. Retention times for 20 µL injections of the selected component mixtures as determined by CI emission for amino acids and PbI emission for organolead compounds correlate well with the corresponding UV absorbance results.

Transmetallation Reaction of 1-Phenylthio- or 1-Tolylthio-2-(2,4,6-tri-t-butylphenyl)-2-phosphaethenyllithium with Copper(II) and Mercury(II)

Abstract: Transmetallation of bulky 1-arylthio-2-(2,4,6-tri-t-butylphenyl)-2-phosphaethenyllithiums with copper(II) and mercury(II) afforded the corresponding 1,4-diphospha-1,3-butadiene derivatives as homocoupled products and organomercury compounds, respectively, which were analyzed by X-ray crystallography.

Phenylmercury Chloride: Its Single-Crystal X-Ray Structure and Some Aspects of its Biological Chemistry

Abstract: A single crystal of phenylmercury chloride (PhHgCl) was obtained by serendipity from a solution of diphenylmercury (HgPh2) and dihydrolipoic acid in tetrahydrofuran / carbon tetrachloride. The crystal structure of PhHgCl is pseudotetragonal. It is best described in the orthorhombic space group Cmma with a = 6.856(1), b = 6.882(1), c = 14.309(2) Å (at 193 K), and Z = 4. The Cl-Hg-C moiety of the PhHgCl molecule is exactly linear. The bond lengths at the Hg atom are Hg-Cl 2.345(2) and Hg-C 2.044(9) Å. In the crystal, the molecules are arranged in double layers parallel to the a,b plane. In a model medium for the gastric juice (0.1 M DCl in D2O / [D8]dioxan, 37 °C), HgPh2 reacts to form PhHgCl. HgCl2, which would result from complete dearylation, cannot be isolated from the reaction mixture. However, it appears that a small equilibrium concentration of HgCl2 may be present, because on addition of 1,4,7-trithiacyclononane (ttcn) and diethyl ether, the dichloride can be trapped as solid [Hg(ttcn)2][HgCl4]. We estimate that after oral uptake of HgPh2 20 -90% are transformed into PhHgCl in the stomach after 30 min

A theoretical study on intramolecular weak interaction of organomercury compounds

Abstract: Twelve organomercury compounds have been studied by means of molecular mechanics MMX force field, semi-empirical PM3 method and ab initio calculations. The distance of Hg and Cl (non-bonded with Hg) in molecules cis -ClHgCHCHCl and o -ClC 6 H 4 HgCl is shorter than the sum of van der Waals radii of Hg and Cl, indicating that there is a weak intramolecular interaction between them.