Diseño de un volcador de contenedores de plástico para el sector hortofrutícola

Treball final de Màster Universitari en Disseny i Fabricació (Pla de 2013). Codi: SIX500. Curs acadèmic: 2017/2018El objetivo es el diseño de un volcador de contenedores de plástico para la descarga de producto alimentario, abasteciendo así las entradas a la línea de tratamiento y transformación en las centrales del sector hortofrutícola. Esta máquina está concebida para el vaciado automático de contendedores llenos de producto alimentario recolectado en el campo. El objetivo del volcador es la descarga del producto de forma continua en la línea de tratamiento y confección en las centrales, buscando un abastecimiento constante para una máxima eficiencia de la línea. Es necesario un sistema de volcado eficiente que a su vez trate al producto de forma delicada y conveniente, manteniendo así una buena calidad del producto sin interferir la productividad

Column classification and selection for the determination of antibiotics by micellar liquid chromatography

Seven commercially available: Zorbax C18, Kromasil C18, C8, cyano, phenyl, monolithic and amino stationary phases columns, have been characterized and classified into broadly similar types to simplify column choice. The results were evaluated employing cluster analysis, which shows several interesting groups based on distances (Minkowski and Euclidean) in agreement with the manufacturer’s claims: chain density of the stationary phase used, and the presence or not a silica base. Finally, results showed that C18 columns offer the best chromatographic characteristics for separation and quantification of antibiotics in micellar liquid chromatography

Micellar liquid cromatography in bioanalytical chemistry

En la cromatografia líquida micel·lar (MLC), la fase mòbil és composta per un surfactant i un alcohol. Els paràmetres que s'han d'optimitzar en la MLC són el tipus de columna, el pH, la naturalesa del surfactant i el modificador, i les seves concentracions. L'optimització es realitza utilitzant una estratègia interpretativa en la qual la millor fase mòbil se selecciona per a estudis de validació. Els mètodes optimitzats en MLC proporcionen separacions ràpides, eficaces, i permeten la determinació d'una gran varietat de substàncies en una matriu complexa. La MLC és una tècnica útil per a identificar medicaments en fluids biològics, que sovint es poden injectar directament al sistema cromatogràfic fins i tot en presència d'uns altres composts, incloent- hi proteïnes, sense cap altre pretractament que la filtració. En descriure les moltes aplicacions de la MLC, aquesta revisió inclou exemples agafats de la literatura, i també resultats recents de la mateixa recerca dels autors. Descriu l'aproximació teòrica, l'estratègia d'optimització i les aplicacions de la MLC en la determinació de grups diferents de substàncies de medicaments. Els compostos i les matrius en discussió són els següents: antidepressius en farmacèutics, agents de blocatge de canal de calci en sèrum, anserina i carnosina en mostres de carns, tiramina i triptamina en vins, i sulfonamides en llet.In micellar liquid chromatography (MLC), the mobile phase is composed of a surfactant and an alcohol. The parameters that must be optimized in MLC are the type of column, the pH, the nature of the surfactant and modifier, and their concentrations. Optimization is performed using an interpretive strategy in which the best mobile phase is selected for validation studies. Optimized methods in MLC provide fast, efficient separations, thereby allowing the determination of a great variety of substances in a complex matrix. MLC is a useful technique for the identification of drugs in biological fluids, which often can be injected directly into the chromatographic system even in the presence of other compounds, including proteins, without any pretreatment other than filtration. In describing the many applications of MLC, this review draws upon examples taken from the literature as well as recent results of the authors' own research. It describes the theoretical approach, optimization strategy, and applications of MLC in the determination of different groups of drug substances. The compounds and matrices under discussion are: antidepressants in pharmaceuticals, calcium-channel blocking agents in serum, anserine and carnosine in meat samples, tyramine and tryptamine in wines, and sulfonamides in milk

Multibiomarker biomonitoring approach using three bivalve species in the Ebro Delta (Catalonia, Spain)

Bivalves have proved to be useful bioindicators for environmental pollution. In the present study, mussels (Mytilus galloprovincialis), cockles (Cerastoderma edule), and razor shells (Solen marginatus) were collected in the Ebro Delta, an extensive area devoted to rice farming and affected by pesticide pollution, from April to July, the heaviest rice field treatment period. Possible effects of pollution were assessed through biochemical markers (carboxylesterase (CE), antioxidant and neurotoxicity-related enzymes, and lipid peroxidation levels). Data on environmental variables, bivalve reproductive condition, and presence of organic pollutants, marine phycotoxins, pathogens, or histopathological conditions in bivalve’s tissues were also evaluated. Although the bioaccumulated pesticides did not explain the patterns observed for biochemical responses, the obtained results point to an effect of environmental pesticide pollution on enzymatic markers, with a prominent contribution of CE to such changes. Mussels and razor shells provided a more sensitive biochemical response to pollution than cockles. Environmental variables, bivalve reproductive condition, and marine phycotoxins did not seem to have a relevant effect on the biomarkers assessed.info:eu-repo/semantics/acceptedVersio

Simultaneous separation and determination of quinolones in pharmaceuticals by micellar liquid chromatography

A rapid and simple liquid chromatographic procedure using micellar mobile phases is reported for the separation and determination of four quinolones (pipemidic acid, levofloxacin, norfloxacin and moxifloxacin) in pharmaceuticals. This purpose was achieved without any previous pretreatment step in a C18 column using a micellar mobile phase of 0.15 M sodium dodecyl sulphate, 2.5% propanol and 0.5% triethylamine at pH 3, with retention times below 12 min. For detection, the diode-array UV-Vis set at 276 nm was used. The limits of detection and quantification were between 8-51 and 28-171 ng/mL, respectively. This method was validated in terms of intra-day and inter-day precision and accuracy, and robustness. Calibration curves over the concentration range of 0.1-50 μg/mL were linear (r2 > 0.9997) and. Good claim percentages (96–106 %) were obtained in the analysis of pharmaceutical formulations. The results show that the procedure is suitable for the routine analysis of drugs

A fast magnetic bead-based colorimetric immunoassay for the detection of tetrodotoxins in shellfish

Tetrodotoxin (TTX) is a potent neurotoxin responsible for many food poisoning incidents and some fatalities. Although mainly associated with the consumption of pufferfish, in recent years, TTX has been found in shellfish, particularly in Europe. In this work, a magnetic bead (MB)-based colorimetric immunoassay was applied to the detection of TTX in Pacific oysters (Crassostrea gigas), razor clams (Solen marginatus) and mussels (Mytilus galloprovincialis). Effective LODs (eLODs) for TTX of 1 μg/kg in oysters and razor clams and 3.3 μg/kg in mussels, significantly below the EFSA guidance threshold (44 μg/kg), were obtained. The strategy was applied to the analysis of naturally-contaminated Pacific oysters (Crassostrea gigas) and mussels (Mytilus edulis) from the Netherlands, and TTX was detected in all samples. The approach, which takes less than 1.5 h, proved to be useful as a rapid and simple method to detect TTX, support shellfish safety and protect consumers.info:eu-repo/semantics/acceptedVersio

Occurrence of tetrodotoxin in bivalves and gastropods from harvesting areas and other natural spaces in Spain

Tetrodotoxin (TTX) is a potent neurotoxin that is receiving increasing interest in the European Union because it has been found in different fishery products (fish, bivalves and gastropods) captured in European waters. Since available information is scarce, further analytical data regarding the incidence of this toxin in European fishery products is needed in order to perform an appropriate risk assessment devoted to protecting consumers’ health. Hence, samples of bivalves and gastropods were collected at different points of the Spanish coast and analyzed by high-performance hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) to evaluate the presence of TTX. None of the analyzed samples showed TTX above an internal threshold of 10 µg/kg or even showed a peak under it. Our results on TTX occurrence obtained in bivalve molluscs and gastropods did not show, at least in the studied areas, a risk for public health. However, taking into account previous positive results obtained by other research groups, and since we did not detect TTX in our samples, a more completed study increasing sampling frequency is needed to ensure proper risk evaluation towards the food safety of these products.info:eu-repo/semantics/publishedVersio

Fast analysis of relevant contaminants mixture in commercial shellfish

One of the major challenges currently faced is to develop systematic ways of addressing chemical mixtures in environmental assessment. With this purpose, a simple, rapid, and sensitive method for the detection and quantification of a mixture of relevant contaminants in molluscs has been developed. The method is based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) and Ultra-High Performance Liquid Chromatography-High Resolution Mass Spectrometry (UHPLC-HRMS). It includes a mixture of 23 compounds formed by pesticides, endocrine disruptors and pharmaceuticals (metolachlor, simazine, desethylatrazine, atrazine, thiabendazole, diazinon, malathion, bentazone, MCPA, propanil, acetamiprid, imidacloprid, caffeine, bisphenol A, triclosan, triclocarban, methylparaben, ethylparaben, propylparaben, 1H-benzotriazole, sulfamethoxazole, venlafaxine and carbamazepine). The method was developed and validated in 4 different types of shellfish of high commercial interest such as mussel (Mytilus galloprovincialis), oyster (Crassostrea gigas), cockle (Cerastoderma edule) and razor shell (Solen marginatus). The mean percentage of recoveries obtained for all the compounds in each mollusc type (intra-specie) ranged from 96% to 107% showing the good performance of the method developed. The relative standard deviation was under 10% for the intra-day and 17% inter-day analyses. Method detection limits and method quantification limits were below 10 ng/g dry weight for all the species and compounds targeted. Finally, the method was applied to aquaculture samples, oysters and cockles, from Ebro Delta (Spain), after some episodes of mortality occurred in 2017. A high level of bisphenol A was detected in C. edule which may explain the mortality suffered by this organism. C. gigas presented low levels of metolachlor, bentazone, acetamiprid, and methylparaben.info:eu-repo/semantics/acceptedVersio