The goals of this Thesis are within the scopes of several research projects carried out in the last years and included within the research lines of the group in which this Thesis has been
performed.
The main goal has been the development of novel, sensitive and selective analytical methods for the determination of several drugs belonging to the antibiotic family called 5-nitroimidazoles (5-NDZs). These compounds are prescribed in human medicine but their use in veterinary medicine is forbidden in the European Union. However, their use is allowed in other countries, so the control of their residues in food is a requirement in order to guarantee that current legislation is enforced. For such a reason, in this Thesis, several methods have been developed for the determination of 5-NDZ residues, including their metabolites, and which are suitable for their application in drug monitoring in biological fluids, food safety and residue determination in environmental field. Miniaturized techniques such as capillary electrophoresis (CE), capillary electrochromatography (CEC), and capillary liquid chromatography (CLC), as well as a high efficiency technique such as ultra-high performance liquid chromatography (UHPLC), have been selected for accomplishing this purpose. These techniques have been coupled to different detection techniques such as ultraviolet-visible (UV-Vis) spectrophotometry and tandem mass spectrometry (MS/MS). Furthermore, both on-line preconcentration (in the case of CE) and off-line preconcentration methods have been proposed, allowing sensitivity enhancement. Moreover, they result in new, more efficiency and environmental-friendly sample treatments for the analysis of 5-NDZ residues, according to the current trends in Green Chemistry.
The following specific goals of this Thesis must be remarked:
- Determination of 5-NDZs by CE-UV in environmental water samples and food products of animal origin, considering both off-line and on-line preconcentration techniques for overcoming the lack of sensitivity attributed to CE-UV.
- Demonstration of the potential of CE-MS/MS hyphenation for the control of
5-NDZ residues in biological fluids, considering the identification capacity of the
selected detection. - Proposal of an efficiency procedure for packing capillaries for their further
application in CEC and consequently, evaluation of the potential of this technique
coupled to UV detection for the determination of 5-NDZs. - Evaluation of CEC-MS hyphenation for the therapeutic monitoring of these drugs
(research carried out in the group of Dr. Salvatore Fanali during a predoctoral stay
in the ‘Istituto di Metodologie Chimiche (IMC) of Consiglio Nazionale delle Ricerche di
Montelibretti’, Rome, Italy). - Use of CLC for the determination of 5-NDZs in food products as alternative to
traditional HPLC. - Investigation of the advantages of UHPLC coupled to both UV and MS/MS
detection, for the quick quantification of 5-NDZ residues in products of animal
origin intended to human consumption. - Proposal of new, simple, quick, selected and environmental-friendly simple treated
for the determination of 5-NDZs, including their metabolites, as alternative to the
methods that have been previously reported. Evaluation of these simple
treatments in different matrices with the aim of demonstrating their suitability in
terms of selectivity and sensitivity.
