Tesi di Dottorato

Permanent URI for this communityTesi di Dottorato

Browse

Subject: search.filters.subject.Cromatografia

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Development and optimization by experimental design of solid phase microextraction gas chromatography triple quadrupole mass spectrometry methods in aqueous matrices
    (2012-11-30) Monteleone, Marcello; Tagarelli, Antonio; Gabriele, Bartolo; Bartolino, Roberto
    Il presente lavoro di tesi relativo all‘attività di ricerca svolta durante il triennio di dottorato ha riguardato la messa a punto di metodi analitici per la determinazione di analiti in due distinte aree di interesse. La prima di ambito clinico ed ha riguardato la quantificazione in urina di metaboliti riconosciuti come marker in diagnostica clinica. In particolare ci si occupati della sarcosina come biomarker del tumore alla prostata, e di tre acidi: acido omovanillico (HVA), acido vanilmandelico (VMA) ed acido 5-idrossindoloacetico (5-HIAA) come marker urinari del neuroblastoma. Il secondo ambito di lavoro ha riguardato la quantificazione di inquinanti in matrici acquose, vale a dire carbammati ed acidi perfluoroalchilici. In particolare gli analiti, previa derivatizzazione con alchilcloroformiati (eccetto i carbammati), sono stati estratti dalle matrici acquose (acqua e urina) tramite la tecnica della microestrazione in fase solida (SPME) e successivamente analizzati mediante un gascromatografo con analizzatore di massa a triplo quadrupolo (GC-QqQ-MS). Le variabili significative della microestrazione in fase solida in ciascun metodo sono state ottimizzate tramite l‘approccio multivariato dell‘ ― Experimental Design‖. L‘utilizzo della tecnica SPME ha consentito di poter estrarre gli analiti direttamente dal campione da analizzare minimizzando i tempi di preparazione dello stesso e riducendo l‘uso di solventi organici, ottenendo metodi poco costosi e basso impatto ambientale. L‘utilizzo dello spettrometro di massa triplo quadrupolo, ha consentito di raggiungere livelli di sensibilità molto elevati e, nel contempo, di identificare gli analiti con maggiore sicurezza. In tutti i metodi sviluppati, sono stati ottenuti ottimi risultati in termini di linearità accuratezza e precisione. Anche i valori dei limiti di rilevabilità (LOD) e dei limiti di quantificazione (LOQ) ottenuti in ciascun metodo possono essere considerati soddisfacenti.
  • No Thumbnail Available
    Item
    Food control quality by isotope dilution liquid chromatography-tandem mass spectrometry
    (2014-06-13) Benabdelkamel, Hicham; Tagarelli, Antonio; Gabriele, Bartolo
    The late part of the 20th century the advancement of knowledge regarding nutrition and disease prevention provided an opportunity for individuals to affect their own health. This expanding body of information helped people to understand how the environment and their own behaviour affected their body. People now had powerful tools to help maintaining and protecting their health. The understanding of how our diet affects our well being has dramatically changed the lifestyles and attitudes of people, who began to make menu and purchasing decisions based on how foods would affect their heath. A shift toward healthier lifestyles and healthier diets began. Food processors and marketers had to refocus their efforts from promoting foods for pleasure to promoting foods that fit in to a healthy diet. Primarily, the focus was on reducing fat and cholesterol in the diet and supplementing vitamins and minerals. Research began to demonstrate the presence of various phytochemicals in wine and juice make it from fruits and vegetables( such as stilbenes, falvoniods, polyphenols…) and specially in olive oil as ( polyphenol in dialdehyed form: oleochanthal, hydroxyoleocanthal..) These compounds have come to be known as nutraceuticals. The list of nutraceuticals present in wine, fruit drink and olive oil that are believed to have positive biological properties has been expanding. Food processors and developers have become very interested in exploiting these nutraceuticals for the production of foods that are not only part of a healthy diet but also improve the consumer’s health in another specific way. These foods have become known as “functional foods” means quality marker. The aim of this thesis has been to develop a analytical methods to determine the concentration of a group of these nutraceuticals in food , such as, quantitative determination of resveratrol in wine, pterostilbene in blueberry juice and dialdehyde form in olive oil using a sensitive high-performance liquid chromatographic separation method coupling with tandem-mass and isotope dilution to order to optimal the conditions for the analysis method, such as extraction procedure, matrices, column, quality controls, wavelength, mobile phases, run time, optimal separation (gradient, retention times), temperature, capillary voltage, cone voltages, vacuum and labelled internal standards, resulting in the best sensitivity and selectivity,The goodness and satisfactory of the method was performed according to, containing linear measuring range, quantification, lower limit of quantification (LLOQ), lower limit of detection (LLOD), quality controls, precision(RSD %), accuracy, recovery, stability and matrix effects. In conclusion, the described high-performance liquid chromatographic separation method with tandem-mass spectrometry detection and isotope dilution showed a satisfactory overall analytical performance well suited for applications in food quality control.