http://www.recercat.cat:80/handle/2072/171808 Tue, 21 May 2013 14:09:41 GMT 2013-05-21T14:09:41Z http://www.recercat.cat:80/bitstream/id/26011/UB.png http://www.recercat.cat:80/handle/2072/171808 http://www.recercat.cat:80/handle/2072/183843 Comparative study of the LC-MS/MS and UPLC-MS/MS for the multi-residue analysis of quinolones, penicillins and cephalosporins in cow milk, and validation according to the regulation 2002/657/EC Junza martínez, Alexandra; Amatya, R.; Barrón Bueno, Dolores; Barbosa Torralbo, José The aim of this study was to develop and validate an analytical method to simultaneously determine European Union-regulated beta-lactams (penicillins and cephalosporins) and quinolones in cow milk. The procedure involves a new solid phase extraction (SPE) to clean-up and pre-concentrate the three series of antibiotics before analysis by liquid chromatography¿tandem mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography¿tandem mass spectrometry (UPLC-MS/MS). LC-MS/MS and UPLC-MS/MS techniques were also compared. The method was validated according to the Directive 2002/657/EC and subsequently applied to 56 samples of raw cow milk supplied by the Laboratori Interprofessional Lleter de Catalunya (ALLIC) (Laboratori Interprofessional Lleter de Catalunya, Control Laboratory Interprofessional of Milk of Catalunya). http://www.recercat.cat:80/handle/2072/183843 http://www.recercat.cat:80/handle/2072/179525 Cryptosporidium sp. in public swimming pools in Barcelona Gómez, María Soledad; Gracenea Zugarramurdi, Mercedes; Ángel Ripoll, Laia; Beneyto, Vicenç The presence of Cryptosporidium oocysts in swimming pools in Barcelona was studied. The possible influence of the different parameters related to water conditions, pool structure and users has also been analyzed. Cryptosporidium oocysts were detected in 54% of the swimming pools analyzed and in 85% of the sport centers checked. Oocysts concentrations ranged from 0 to 30 oocysts/L. Among parameters related to water conditions, there was no relationship between oocyst presence and water pH, but the influence of temperature was statistically significant (p"MENOR QUE"0.05) (¿2=0.024). Among parameters related to pool structure, the filter backwash water samples revealed a higher percentage of parasitation (58.8%) than the prefilter ones (42.9%). With the medium volume pools (100-500 m3), the percentage was higher (80%). Covered and uncovered pools presented similar prevalences for Cryptosporidium oocysts. Looking at two of the user related parameters, swimming pools with more users and children's swimming pools showed http://www.recercat.cat:80/handle/2072/179525 http://www.recercat.cat:80/handle/2072/172079 Metal complexation by electroanalytical techniques: hard- and soft-modelling approaches Ariño Blasco, Cristina; Díaz Cruz, José Manuel; Esteban i Cortada, Miquel En la investigació de la complexació de metalls mitjançant eines electroanalítiques són emprades dues aproximacions generals. La primera, anomenada de modelatge dur (hardmodelling), es basa en la formulació d'un model fisicoquímic conjunt per als processos electròdic i de complexació i en la resolució analítica o numèrica del model. Posteriorment, l'ajust dels paràmetres del model a les dades experimentals donarà la informació desitjada sobre el procés de complexació. La segona aproximació, anomenada de modelatge tou (soft-modelling), es basa en la identificació d'un model de complexació a partir de l'anàlisi numèrica i estadística de les dades, sense cap assumpció prèvia d'un model. Aquesta aproximació, que ha estat extensivament emprada amb dades espectroscòpiques, ho ha estat poquíssim amb dades electroquímiques. En aquest article tractem de la formulació d'un model (hard-modelling) per a la complexació de metalls en sistemes amb mescles de lligands, incloent-hi lligands macromoleculars, i de l'aplicació d http://www.recercat.cat:80/handle/2072/172079