Leandro Castillo Martínez

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Papers by Leandro Castillo Martínez

Talanta, 1998

A method for the determination of silicon by inductively coupled plasma atomic emission spectrome... more A method for the determination of silicon by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The procedure is based on a discontinuous generation of volatile silicon tetrafluoride in concentrated sulphuric acid medium after injecting 125 μl of 0.1%, w/v sodium fluoride solution into 100 μl of the sample. The gaseous silicon tetrafluoride is fed directly into the ICP torch by a flow of 250 ml min−1 Ar carrier gas. The calibration curve was linear up to at least 100 μg ml−1 of Si(IV) and the absolute detection limit was 9.8 ng working with a solution volume of 100 μl. The relative standard deviation for six measurements of 10 μg ml−1 of Si(IV) was 2.32%. The method was applied to the determination of silicon in water and iron ores.

Analytical and Bioanalytical Chemistry, 2009

An experimental approach to evaluate the capabilities and limitations of polyacrylamide gel elect... more An experimental approach to evaluate the capabilities and limitations of polyacrylamide gel electrophoresis (PAGE) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for quantitative elemental speciation is presented. Two metalloproteins (superoxide dismutase, containing Cu and Zn, and thyroglobulin, containing I) with high binding affinity for metals, and metal-dissolved organic matter (DOM) complexes (from a compost leachate sample) which show different types of metal binding are studied. Iodine can be quantitatively detected in thyroglobulin after PAGE-LA-ICP-MS using either sodium dodecyl sulfate (SDS) PAGE or native PAGE. However, detection of Cu and Zn in superoxide dismutase after PAGE-LA-ICP-MS depends on the conditions of the PAGE method because possible metal losses can occur (either with SDS-PAGE or with native PAGE). The use of PAGE-LA-ICP-MS to study the contribution of DOM to the mobilization of metals from environmental samples is possible, but it depends also on the PAGE separation conditions owing to disequilibrium effects of metal-DOM complexes.