Improvement of the semiautomated headspace analysis method for the determination of methylmercury in biological samples

An improvement in the extraction step in the method of Decadt et al. for determining methylmercury in biological tissues is described. The methylmercury is released from the tissue by use of sulphuric acid as the cleaving agent and immediately converted to the iodide form by iodoacetic acid. These reaction steps take place in a closed headspace vial. The methylmercury iodide is then headspace-injected into a gas-chromatograph and detected with a microwave-induced plasma detector. Quantitation is accomplished by standard addition. Analysis of one sample takes less than 15 min. The detection limit of the method is 20 ng methylmercury per gram biological tissue when 50 mg of tissue are taken

Determination of methylmercury in natural waters by headspace gas chromatography with microwave-induced plasma detection after preconcentration on a resin containing dithiocarbamate groups

A method for the determination of methylmercury at ng 1-1 levels in natural waters is described. Methylmercury present in a sample is first preconcentrated on a column of a resin containing dithiocarbamate groups and eluted quantitatively with acidic thiourea solution. Methylmercury in the effluent is then converted to the iodide by addition of sulphuric acid and iodoacetic acid and determined by headspace gas chromatography with microwave-induced plasma detection. The adsorption properties of the resin are discussed

Preconcentration, speciation, and determination of key elements in biological samples in Latin America

The concentrations of trace elements in biological samples are far below those achieved directly by most atomic or plasma-based techniques and the detection power needs to be improved by the use of a preconcentration step. In this connection, solid phase extraction (SPE) makes possible the concentration and purification of analytes from solution by their sorption onto a solid sorbent, also improving detection limits. The challenge to determine metallic species in biological samples resides mainly in the complexity of these types of matrices as well as the low concentrations of target elements. Analytical chemistry has provided many solutions to this end, thanks to the development of innovative, sensitive, and selective methods. In recent years, the analysis of key elements in human tissues has gained great interest owing to the role that these elements play in biochemical and physiological processes. Although trace elements constitute a minor part of living tissues, they are important for vital processe.Fil: Pacheco, Pablo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Gil, Raul Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Martinez, Luis Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Smichowski, Patricia Nora. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin