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Treball Final de Grau en Química. Codi: QU0943. Curs: 2015/2016 In this work, a gas chromatography coupled to mass spectrometry (GC-EI-Q(MS)) has been used for markers identification for a metabolomics approach. It has been carried out in order to create a statistical model to perform a correct classification between different quality olive oils (extra, virgin and lampante). A dynamic headspace purge and trap (DHS-P&T) was used to the extraction of volatile organic compounds (VOCs) responsible for olive oil flavours and they were eluted from the SPE cartridges with a mixture of hexane:diethyl ether (50/50, v/v). The methodology is based on the application of P&T extraction followed by gas chromatography coupled to mass spectrometry in full-spectrum acquision mode. The data acquired by this equipment was pre-treated by a new program called PARAFAC. After that these acquired data was normalized and the differentiation between the different groups of olive oil has been carried out with a multivariate analysis using Ez-Info. This methodology was applied to process 47 olive oil samples (11 extra, 19 virgin, 17 lampante) in order to create and check the classification model. The different models were performed with 37 samples. Finally, the whole developed method was correctly validated by the other 10 samples which were kept for the validation. Four of the seven evaluated model achieved around a 60% of correct classification. And with one of the studied models was obtained a classification of 90%. So with that result, it can be said that with this methodology and with these markers the PANEL TEST could be substituted.

Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic 2014-2015 Determining the quality of olive oil has always been a conflict, as to date, the only way that was available for classification was through tasting by a panel of experts. This differentiation, performed by a quite subjective method, could be complex, and sometimes leads to large discrepancies in the organoleptic qualities of the same oil depending on the taster to try it. Such discrepancies may result in misclassification of the oil, resulting in economic harm to producers, to determine a quality below the real to a particular product. The progress each day over chromatographic techniques coupled to mass spectrometry allows to reach detect differences in concentrations of trace compounds even in the range of parts per trillion. Through these techniques it can be quantified with high accuracy at these levels, something impossible for a tasting panel or other physicochemical techniques. In the same way, in highlighting differences between large groups of samples, technical progress with high resolving power, and the development of new information technologies has facilitated the emergence of complex statistical analyzes that allow, based a previous model, a sample assignment within a given group with a minimum data treatment. In this field, metabolomics is the most efficient methodology, as it allows, through statistical analysis of individual samples, create patterns of behavior of different groups and thus classify blind samples in each group with minimal error. In this work, a metabolomics approach has been carried out in order to create a statistical model to perform a classification between different quality olive oils. Hybrid quadrupole timeof- flight mass spectrometer (QTOF MS) coupled to gas chromatography (GC) has been used for untargeted metabolite fingerprinting. Differentiation from Extra Virgin olive oil, Virgin olive oil and Lampante olive oil has been carried out using XCMS application and multivariate analysis to GC-(Q)TOF MS data acquired. Finally an alternative technique, more selective and economical also based on purge and trap, but taking profit of the benefits of the direct thermal desorption in the injection system of a GC, coupled to a single quadrupole (MS) has been developed.

Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic 2014-2015 Throughout the last decades the huge demand on fish supply has led the world fish stocks to be over exploited. Aquaculture has appeared to be the solution for this situation, becoming the essential way of supplying the demand of fish products. However, the traditional aquaculture feed has been composed mainly of fish raw materials. At this moment, one of the main goals of aquaculture is to reduce the utilisation of marine origin ingredients in aquafeeding and to substitute them by vegetable origin material. Those novel diet compositions could introduce new and unexpected undesirables in feed composition, and therefore, arrive to fish organism. The investigation was devoted to polycyclic aromatic hydrocarbons (PAHs) and pesticides because of their widespread presence and also motivated by recent European Commission regulations for PAHs and pesticides in foodstuffs. So, the objective of this investigation was to assess the transference of any polycyclic aromatic hydrocarbon or pesticide present in some diets to fish tissue. For accomplishing this objective, high resolution screening techniques were used: gas chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry with atmospheric pressure chemical ionisation (GC-(APCI)-QTOF MS) and, ultra high pressure liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry with electrospray source of ionisation (UHPLC-(ESI)-QTOF MS). Four PAHs (fluoranthene, naphthalene, phenanthrene and pyrene) and three pesticides (ethoxyquin, ethoxyquin dimer and pirimiphos-methyl) were present in both feed and fish tissue in all examined diets. This work has been partly carried out under the EU Seventh Framework Programme by ARRAINA Project 288925: Advanced Research Initiatives for Nutrition and Aquaculture.