Analytical strategies to study metals in environmental matrices by inductively coupled plasma mass spectrometry

Abstract

This Doctoral Thesis presents validated analytical strategies to assess metallic contamination (metals and their chemical forms) in marine sediments and river waters by ICP-MS applying the principles of the Green Analytical Chemistry. Thus, several studies were performed in sediment samples of two Galician rias. The metallic bioaccessible fraction was accurately evaluated through the simultaneously extracted metals (SEM) and the acid volatile sulfides (AVS). The SEM-AVS ratio was calculated to evaluate the metallic contamination risk. The isotope dilution analysis allowed to improve the results in the determination of the bioaccessible fractions of cadmium and chromium, since is not affected by analyte losses and in addition is a low time-consuming procedure. The total content of these elements was determined by the direct analysis of the solid samples with laser ablation coupled to ICP-IDMS synthetizing a unique solid spike. River water samples were analyzed for the simultaneous determination of organometallic compounds of mercury, tin and lead using large volume injections in a programmable temperature vaporizer coupled to GC-ICP-MS. This new methodology provided detection limits well below the actual directive requirements. Also, it is addressed a statistical study of the standard addition method in classical calibration and the mass discrimination factor in isotope dilution.