ABSTRACT

Antibiotics are widely used in veterinary medicine, producing huge benefits, but also environmental risks due to the occurrence of “uncontrolled” residues that can trigger bacterial resistance, allergic reactions and other important inconvenients. 
In this thesis several systems for determining immunochemical residues of different types of antibiotics have been developed, both through traditional ELISA plate format and through microarrays using CDs as analytical platforms.
First, ELISA plate immunoassays for sulfonamides and tetracyclines have been developed: two generic immunoassays for the determination of six sulfonamides with high sensitivity (IC50 values between 1.32 and 12.82 ng mL-1) and specific immunoassays for the determination of SSZ and SMX with IC50 values of 0,51 and 0.16 ng mL-1, respectively. It also has been developed a specific immunoassay for the determination of CTC, with IC50 value of 36.40 ng mL-1. These ELISAs have been successfully applied to the quantification of sulfonamide residues in food (honey), sewage waters and human plasma.
Another section presents the results of research on the development of microinmunoensayos using the technology of compact discs. This platform has large analytical area to deposit thousands of probe biomolecules and the ability to integrate both numerically and biochemical information (identifying each point of each array and storing test results on the same physical platform in which the analysis is developed); moreover, its large scale manufacturing allows high quality products at low prices. In addition, analytical results are read and quantified by a commercial CD player integrated into a conventional personal computer.
Two generic micro-CD immunoassays for the determination of five sulphonamides, with IC50 values between 0.22 and 1.98 ng mL-1 as well as specific microinmunoensayos for SMX, able to determine a value of IC50 1.09 ng mL-1, and CTC, with an IC50 value of 6.33 ng mL-1 have been developed. The microinmunoensayos have been successfully applied to the quantification of sulfonamide residues in food samples (fish) and environmental (sewage water).
Therefore, it has been demonstrated that the use of low reflectivity disks (L-CD) and a CD player is a very suitable methodology for the determination of substances in high density format, with a sensitivity level of nanograms per liter, comparable to that obtained on ELISA plate using the same immunoreactives.