Identifier: TDX:768
Authors: Gimeno Ferreres, Rosa Ana
Abstract:
The aim of this thesis has been the development of analytical methods for the determination of some groups of organic contaminants in coastal water and sediment samples.These methods were based on the coupling of high-performance liquid chromatography to different detection techniques, such as fluorescence detection or mass-spectrometry, as well as the on-line and off-line coupling to different extraction techniques.As detectors, the developed methods used UV-visible detector, since it is commonly used. However, due to the low concentration levels to be achieved when real environmental samples are analysed, more sensitive detectors, such as fluorescence detector or mass spectrometry, are preferred. So these detectors have been used for the determination of some of the families of compounds studied in this thesis. As regards to coupling mass spectrometry to high-performance liquid chromatography, the atmospheric-pressure chemical ionization interface has been chosen because of the ionization characteristics of the studied compounds.Referring to the extraction techniques, solid-phase extraction has been chosen for the analysis of aqueous samples. This technique has been coupled on-line and off-line to the high-performance liquid chromatography. Taking into account the characteristics of the compounds, different polymeric sorbents have been used. In this way, PLRP-s, a styrene-divinylbenzene copolymer, has been used for the determination of polycyclic aromatic compounds. But due to the development of the highly-crosslinked polymeric sorbents, which present a greater retention of the most polar compounds, and taking into account the good results obtained for the extraction of other organic contaminants for other kinds of aqueous samples, these kind of sorbents was also used in some of the studies. Between them, LiChrolut EN and Isolute ENV+ were chosen.For the analysis of sediment samples, the extraction of the analytes was carried out using an organic solvent that is kept in contact with the sample. To be concrete, this technique, which is simpler than others, has been used for the extraction of different compounds using acetonitrile or dichloromethane as solvents. To improve the extraction of some of the studied compounds, in some cases ultrasonic extraction has been chosen.In addition to the development of analytical methods based on coupling of different techniques to the high-performance liquid chromatography, it is also important to mention the use of two second-order calibration algorithms, the 3-PLS (three-way Partial Least Squares) and the GRAM (Generalized Rank Annihilation Method), in some of the studies, as a mathematical tool to solve some of the problems arisen in the determination of the studied compounds, such as quantification from overlapped peaks, which allows the decrease in the analysis time, or quantification in very complex samples, such as marine sediment samples, which usually present matrix effect, by using only one calibration sample, which allows quantification without carrying out a new calibration for every new sample.In all the presented studies, the developed methods have been applied to the analysis of real samples taken from the ports of Tarragona, although some samples of the wastewater treatment plant of this city have also been analysed in order to evaluate its effect into the contamination in the coastal environment. Moreover, some samples taken from the river Ebre have also been analysed. It is also important to highline the method developed for the determination of some antifouling pesticides, since this method allowed the monitorization of the presence of the studied compounds in samples from different ports of the coast of Tarragona during a period of five months.
Repositori URV