Quantification and monitoring of inorganic contaminants relevant for environmental and health risk assessment

This thesis is the compilation of published and unpublished works on the development and improvement of analytical methodologies for the quantification of inorganic compounds. It aims to provide a new contribution to the field of the environmental analytical chemistry, developing new methods for fast, accurate and low-cost quantification of metals and inorganic anions in diverse matrices. The presented strategies are based on the direct determination of the analyze with inductively coupled plasma – mass spectrometry, or on analyte derivatization to volatile species and coupling with gas chromatography or atomic spectroscopy for detection. Some clarifying aspects on the mechanisms of common derivatization techniques (chemical vapour generation and alkylation) are also presented. The work is divided into three sections: Sections 1 and 2 have in common chemical derivatization to improve analyte detection, while in Section 3 is presented the direct analysis of real sample without any chemical modification of the analytes. In Section 1, I discuss some fundamental aspects of photochemical vapor generation as an alternative analytical technique for the quantification of metals and organometallic compounds. The application of PVG to the detection of mercury and selenium is presented. Section 2 focuses on the application of chemical derivatization for the gas chromatography – mass spectrometry analysis of cyanide and thiocyanate. Technical details and fundamental aspects of derivatization chemistry and calibration strategy are presented. Finally, in Section 3 I present the use of the inductively coupled plasma – mass spectrometry coupled with liquid chromatography for the monitoring and speciation of heavy metals (thallium and copper) in water and living organisms.