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Preparation of a carbon paste electrode with DPB as a binder and NaTPB as a precipitation reagent, for the determination of the pharmaceutical maprotiline : diploma thesis
No full textElektrode na bazi ugljikove paste su uvelike korištene u elektroanalizi zbog mnogih prednosti poput širokog raspona električnog potencijala, mogućnosti izrade i uporabe elektroda s mnoštvom različitih kombinacija sastavnih elemenata, svoje kemijske inertnosti i prihvatljive cijene. U ovom radu pripremljen je niz elektroda s ugljikovom pastom uz dibutilftalat kao tekućinu za lijepljenje te ionsko-asocijacijskim kompleksom – maprotilinov tetrafenilboratom prethodno istaloženim u laboratoriju, za određivanje farmaceutika maprotilin hidroklorida, u koncentracijskom području od 3,16·10 -6 do 3,16·10 -3 M pri pH=4,5. Pripravljeno je i ispitano 16 elektroda s različitim omjerima grafita, veziva, ionsko-asocijacijskog kompleksa i dodataka za poboljšanje odziva; ionske soli i grafen. Najbolje odzivne karakteristike je pokazala elektroda 12, koja se sastoji od 49,16% grafita, 49,16% dibutilftalata, 1,48% ionsko-asocijacijskog kompleksa i 0,20% natrijevog tetrafenilborata. Na taj način izrađena elektroda je pokazala promjenu potencijala po koncentracijskoj dekadi od 52,14 mV u linearnom dinamičkom rasponu od 3,16·10 -6 do 3,16·10 -3 M.Carbon-based electrodes have been widely used in electroanalysis due to many advantages such as wide range of electric potential, the ability to make and use electrodes with many different combinations of components, their chemical inertness and reasonable price. A series of graphite-based ion-selective electrodes were prepared with dibutyl phthalate as a binder with a dissolved ion-association complex – maprotiline tetraphenylborate for the determination of maprotiline hydrochloride, pharmaceutical, in the concentration range from 3,16·10 -6 to 3,16·10 -3 M at pH = 4,5. 16 electrodes with different ratios of graphite, binder, ion-association complex and additives to improve the response: ionic salt and graphen were prepared and tested. The best response characteristics were shown by electrode 12, which consists of 49,16% graphite, 49,16% dibutyl phthalate, 1,48% ionic- association complex and 0,20% sodium tetraphenylborate. The electrode made in this way showed a change in potential per concentration decade of 52,14 mV in the linear dynamic range from 3,16·10 -6 to 3,16·10 -3 M
Difference in the chemical profile of alga Halopteris scoparia with regard to the growth location : diploma thesis
No full textAlge su višestanični autotrofni fotosintetski organizmi. Osnovna podjela je na mikro i makroalge. Osim navedene podjele, alge se dijele prema dominirajućem pigmentu na: zelene (Chlorophyta), crvene (Rhodophyta) i smeđe (Phaeophyta). Smeđe alge sadrže karotenoid fukoksantin koji prekriva zelenu boju klorofila i daje im karakterističnu boju. Pričvršćene su na podlogu (bentos) npr. kamenja, stijene ili pak druge alge. Halopteris scoparia (Linnaeus) Sauvageau, 1904 je smeđa alga. Raste u širokom temperaturnom rasponu na području diljem Europe, Baltika (sjeverna granica distribucije) te Nigerije (južna granica distribucije). H. scoparia svoju primjenu pronalazi u prehrambenoj, farmaceutskoj i kozmetičkoj industriji i ekologiji. Analizom provedenom na svježim i suhim uzorcima H. scoparia sa dvije lokacije uočena je razlika u kemijskom profilu isparljivih spojeva s obzirom na lokaciju rasta. Isparljivi spojevi izolirani su metodom hidrodestilacije i analizirani plinskom kromatografijom sa spektrometrijom masa. Usporedbom dobivenih podataka kemijskog profila uočena je razlika u sadržaju alifatskih nezasićenih i zasićenih spojeva, derivata benzena, terpena i derivata klorofila. Uzorci H. scoparia s područja obale otoka Čiovo bogatiji su alifatskim nezasićenim spojevima (42,06%, svježe; 36,82%, suho) od uzoraka s područja Zadar, Punta Bajlo (28,87%, svježe; 23,03%, suho). Također, razlika u kemijskim profilima uočava se kod zastupljenosti derivata klorofila. U uzorku s područja Zadar, Punta Bajlo zastupljenost navedenih spojeva bila je gotovo dvostruko veća (19,13%, svježe; 14,03%, suho) nego u uzorku s područja obale otoka Čiovo (7,89%, svježe; 11,72%, suho). Na osnovu provedenog istraživanja može se zaključiti da lokacija rasta utječe na kemijski profil alge H. scoparia.Algae are multicellular autotrophic photosynthetic organisms. The basic division of algae is into micro and macroalgae. In addition to the above division, they are divided according to the dominant pigment into: green (Chlorophyita), red (Rhodophyta) and brown (Phaeophyta). Brown algae contain carotenoid fucoxanthin which covers green color of chlorophyll and gives their characteristic color. They are attached to the base (bentos) like stones, rocks or other algae. Halopteris scoparia (Linnaeus) Sauvageau, 1904 is brown alga. It grows in a wide temperature range across Europe, the Baltcis (northern limit of distribution) and Nigeria (southern limit of distribution). H. scoparia finds its application in the food, pharmaceutical and cosmetic industries and ecology. The analysis performed on fresh and dry samples of H. scoparia from two locations showed a difference in the chemical profile with respect to the location of growth. The volatile compounds were isolated by hydrodistillation and analyzed by gas chromatography with mass spectrometry. A comparison of the obtained chemical profiles showed a difference in the content of aliphatic unsaturated and saturated compounds, benzene derivatives, terpenes and chlorophyll derivatives. The sample of H. scoparia from the coast of the island Čiovo are richer in aliphatic unsaturated compounds (42,06%, fresh; 36,82%, dry) than the sample from area of Zadar, Punta Bajlo (28,87%, fresh; 23,03%, dry). Also, the difference in the profile is observed in the presence of chlorophyll derivatives. In the sample from area of Zadar, Punta Bajlo the prevalence of these compounds was almost twice as high (18,13%, fresh; 14,03%, dry) than in the sample from the coast of the island Čiovo (7,89%, fresh: 11,72%, dry). Based on the above it can be concluded that the location of growth and the environment affect the chemical profile of the alga H. scoparia
Comparison of volatile compounds of Dalmatian pancetta, Istrian pancetta and Schwartwald bacon : diploma thesis
No full textU ovom radu analiziran je kemijski sastav hlapljivih spojeva dalamtinske i istarske pancete te schwarzwaldske slanine. Hlapljivi spojevi izolirani su mikroekstrakcijom vršnih para na krutoj fazi (HS-SPME) korištenjem plavog i sivog vlakna. Analiza izoliranih hlapljivih spojeva uzoraka provedena je metodom plinske kromatografije – spektrometrije masa (GC-MS). Dobiveni rezultati ukazuju kako različiti postupci prerade i proizvodnje utječu na različitost u sastavu hlapljivih aromatskih spojeva analiziranih proizvoda.In this paper, the chemical composition of the volatile compounds of Dalmatian and Istrian pancetta and Schwarzwald bacon was analyzed. Volatile compounds were isolated by solid phase peak vapor microextraction (HS-SPME) using blue and gray fibers. The analysis of the isolated volatile compounds of the samples was performed using the gas chromatography - mass spectrometry (GC-MS) method. The obtained results indicate that different processing and production processes affect the difference in the compositi on of volatile aromatic compounds of the analyzed products
Application of ultrafiltration in drinking water treatment in the Dubrovnik area : diploma thesis
No full textU ovome radu proveden je detaljan prikaz i analiza uređaja za obradu pitke vode na izvorištu rijeke Omble (UPPV Komolac). Primijenjeni postupak uključuje ultrafiltracijsku separacijsku tehniku koja omogućuje stabilnu i sigurnu vodoopskrbu grada Dubrovnika, neovisno o značajnim promjenama u kvaliteti „sirove vode“. U radu su analizirane sve faze postupka obrade „sirove vode“: predobrada, ultrafiltracija, povratno ispiranje, dezinfekcija i distribucija pitke vode. Djelotvornost uređaja sagledana je preko vrijednosti mutnoće, ukupnog broja koliforma i Escherichiae coli u sirovoj i obrađenoj vodi i to u razdoblju od listopada 2019. do svibnja 2020. godine. Po izvršenoj obradi vode u UPPV Komolac može se zaključiti da su vrijednosti navedenih parametara djelovanjem ultrafitracijskog postrojenja značajno smanjene. Najviša izmjerena vrijednost mutnoće obrađene vode u analiziranom periodu iznosila je 0,6 NTU, što ukazuje na izuzetnu učinkovitost postrojenja. Djelotvornost ultrafiltracije na uklanjanje koliformnih bakterija i Escherichiae coli nije moguće definirati, jer u sirovoj vodi, u analiziranom periodu, nije uočena prisutnost navedenih mikrobioloških pokazatelja. Uporaba analizirane membranske tehnologije definitivno osigurava visoku kvalitetu vode za piće Dubrovačko-neretvanske županije.In this paper, a detailed presentation and analysis of treatment plant for drinking water at source of Ombla river (UPPV Komolac) was performed. The applied procedure includes an ultrafiltration separation technique that enables a stable and secure water supply of the city Dubrovnik, regardless of significant changes in the quality of "raw water". The paper analyzes all phases of the "raw water" treatment process: raw water pretreatment, ultrafiltration, backwash, disinfection and distribution of drinking water. The efficiency of the plant was assessed through the values for turbidity, the total number of coliforms and Escherichiae coli in raw and treated water in the period from October 2019 to May 2020. After the water treatment in UPPV Komolac, it can be concluded that the values of these parameters are significantly reduced by the ultrafiltration operation. The highest measured value of turbidity of treated water in the analyzed period was 0,6 NTU, which indicates the exceptional efficiency of the plant. The effectiveness of ultrafiltration related to the removal of coliform bacteria and Escherichiae coli cannot be defined, since in given period, the presence of these microbiological indicators in the raw water was not observed. The use of the analyzed membrane technology definitely ensures the high quality of drinking water in the Dubrovnik- Neretva County
Impact of zeolite mass on copper sorption : diploma thesis
No full textU ovom radu ispitan je utjecaj mase zeolita NaX na kinetiku sorpcije iona bakra i na utrošak snage suspendiranja u šaržnom reaktoru bez i s razbijalima virova. Eksperimenti su provedeni pojedinačnim korištenjem tri različite mase zeolita NaX veličine čestica 0,063 - 0,090 mm pri minimalnoj brzini vrtnje miješala pri kojoj se postiže stanje potpune suspenzije (N JS ) i konstantnoj temperaturi suspenzije. Korišteno je turbinsko miješalo s ravnim lopaticama (SBT). Kinetička analiza dobivenih eksperimentalnih podataka Weber-Morrisovim i Blanchardovim kinetičkim modelima pokazala je kako Blanchardov model bolje opisuje kinetiku sorpcije iona bakra na zeolitu NaX za sve korištene mase u eksperimentu što pokazuje da se proces odvija u kinetičkom području, odnosno da je ispitivana reakcija drugog reda čija brzina ovisi o masi zeolita, i u sustavu bez i s razbijalima virova.In this paper, the influence of NaX zeolite mass on the kinetics of copper ions sorption and the suspension power consumption, in the unbaffled and baffled batch reactor, was investigated. The experiments were carried out using three different masses of zeolite NaX with a particle size of 0.063 - 0.090 mm at a minimum impeller speed at which the state of complete suspension is achieved (N JS ) and constant suspension temperature. A straight blade turbine impeller (SBT) was used. Kinetic analysis of the obtained experimental data by Weber-Morris and Blanchard kinetic models showed that Blanchard's model better describes the kinetics of copper ions sorption on NaX zeolite for all masses used in the experiment. This shows that the process is reaction controlled and that the reaction is of the second-order, depending on the mass of the zeolite, in the unbaffled and baffled system
Determination of selected cannabinoids using UHPLC-MS/MS technique : master thesis
No full textKanabinoidi su spojevi koji se u posljednje vrijeme sve više istražuju radi svojih ljekovitih svojstava. Od osobite su važnosti nepsihoaktivni spojevi poput kanabidiola te njegovi derivati i metaboliti. Tekućinska kromatografija je jedna od najnaprednijih separacijskih tehnika u analitičkoj kemiji. U sprezi s detektorom masa u tandemu predstavlja i moćnu identifikacijsku i kvantifikacijsku tehniku. U radu je korištena tekućinska kromatografija visoke djelotvornosti spregnuta s detektorom masa s trostrukim četveropolom kao analizatorom u svrhu kvantitativnog i kvalitativnog određivanja kanabidiola, njegovog kiselinskog derivata – kanabidiolne kiseline te dva najznačajnija metabolita: 7-hidroksikanabidiola i 7-karboksikanabidiola.In the recent times cannabinoids have been increasingly researched for their medicinal properties. Non- psychoactive compounds such as cannabidiol and its derivatives and metabolites are of particular importance. Liquid chromatography is one of the most advanced separation techniques in analytical chemistry. When coupled with a tandem mass detector it represents a powerful identification and quantification technique. In this diploma thesis a high-performance liquid chromatography coupled with a triple quadrupole mass detector was used for the quantitative and qualitative determination of cannabidiol, its acid derivative - cannabidiolic acid, and the two most important metabolites: 7-hydroxycannabidiol and 7-carboxycannabidiol
Sensory and aromatic profile of smoked hams : master thesis
No full textCilj ovog rada bio je identificirati hlapljive spojeve hrvatskih tradicionalnih dimljenih pršuta te odrediti senzorska svojstva istih. Tijekom procesa proizvodnje pršuta odvija se niz biokemijskih reakcija koje su zasluţne za formiranje boje, teksture i arome pršuta. Najvaţnije biokemijske reakcije tijekom kojih nastaje niz hlapljivih spojeva odgovornih za aromu pršuta su lipoliza i proteoliza. Izolacija hlapljivih spojeva pršuta provedena je mikroekstrakcijom vršnih para na ĉvrstoj fazi (HS-SPME), a spojevi su identificirani vezanim sustavom plinske kromatografije-masene spektrometrije (GC-MS). Identificirani hlapljivi spojevi svrstani su u sljedeće skupine: aldehidi, fenoli, alkoholi, esteri, kiseline, ketoni, alifatski i aromatski ugljikovodici, spojevi sa dušikom, spojevi sa sumporom i terpeni. MeĊu identificiranim spojevima najzastupljeniji su bili aldehidi, potom fenoli i ketoni. Senzorska analiza provedena je od strane 10 ocjenjivaĉa korištenjem nestrukturirane linijske skale. Sinergijom arome, boje i teksture stvara se senzorski profil pršuta. Tijekom senzorske analize uzorak 1 je dobio najveće ocjene za većinu pozitivnih karakteristika, dok su uzorci 4 i 6 ocjenjeni niţim ocjenama. Ni u jednom od uzoraka nisu pronaĊeni kristali tirozina te aroma na biokemijsko, po svjeţem mesu i po aromatiĉnom bilju.The aim of this study was to identify volatile compounds of traditional Croatian smoked hams and to determine their sensory properties. Series of biochemical reactions occurs during the production process which are responsible for the formation of color, texture and aroma of smoked hams. Lipolysis and proteolysis are the most important biochemical reactions which generate a number of volatile compounds that are responsible for the formation of ham aroma. The volatile compounds were isolated by headspace-solid phase microextraction (HS-SPME), and identified by gas chromatography-mass spectrometry (GC-MS) technique. Identified volatile compounds are classified into the following groups: aldehydes, phenols, alcohols, esters, acids, ketones, aliphatic and aromatic hydrocarbons, compounds with nitrogen, compounds with sulfur and terpenes. Among identified compounds aldehydes were the most abundant compounds, then phenols and ketones. Sensory analysis was performed by 10 panelist using an unstructured linear scale. The sensory profile of hams is created through the synergy of aroma, color and texture. During the sensory analysis sample 1 received the highest grade for the majority of positive characteristics, while samples 4 and 6 were rated with lower grades. Tyrosine crystals, biochemical aroma, aroma of fresh meat and aromatic herbs were not found in any of the samples
Edible packaging materials : bachelor thesis
No full textSama ideja o upotrebi jestivih zaštitnih filmova već duže vrijeme zaokuplja pažnju znanstvenika. Postupak prevlačenja hrane bilo voskovima ili želatinom patentiran je daleke 1800. godine. Jestivi filmovi nalaze se u upotrebi već niz godina (želatina, kapsule, ovitci za kobasice, prevlake od čokolade, šećera i od voska). Funkcija jestive ambalaže je ponuditi selektivnu prepreku za usporavanje migracije vlage, transporta plina, migracije ulja i masti te transporta otopljene tvari; poboljšati mehanička svojstva rukovanja hranom; poboljšati mehanički integritet ili osobine rukovanja hranom; zadržavati hlapljive spojeve okusa i nositi aditive za hranu poput antioksidansa i antimikrobnih sredstava. U ovom završnom radu objašnjeno je što je jestiva ambalaža, njezine vrste, svojstva kao i sama svrha primjene. U budućnosti se očekuje povećanje upotrebe jestivih materijala, njihov razvoj te poboljšanje svojstava.The idea of using edible protective films has long captured the attention of scientists. The process of coating food with wax or gelatin was patented as far back as the 1800s. Edible films have been used for many years (gelatin, capsules, sausage casings, chocolate, sugar and wax coatings). The function of edible packaging is to offer a selective barrier to retard the migration of moisture, gas transport, oil and fat migration and solute transport; improve the mechanical handling properties of foods; improve the mechanical integrity or handling characteristics of the food; retain volatile flavor compounds and carry food additives such as antioxidants and antimicrobials. In this bachelor thesis, it is explained what edible packaging is, its types, properties as well as the purpose of application. In the future, it is expected to increase the use of edible materials, their development and improved properties
Binding of lead ions to zeolite onto the presence of Humistar r solution of different concentration and ptf values : diploma thesis
No full textU ovom radu ispitano je vezanje iona olova na prirodnom zeolitu klinoptilolitu u prisutnosti otopine Humistar ® koja sadrži visoki udio huminskih kiselina i drugih organskih spojeva te tako simulira organske tvari prisutne u tlu. Eksperimenti su provedeni s otopinama različitih početnih koncentracijama iona olova te je ispitan utjecaj prisustva huminskih kiselina na točnost određivanja koncentracije olova metodom kompleksometrijske titracije. Eksperimenti vezanja olova na prirodnom zeolitu u otopinama različitih početnih koncentracija olova i različitih početnih koncentracija Humistar ® otopina provedeni su pri različitim pH vrijednostima. Pri višim koncentracijama iona olova utvrđena je veća količina vezanog olova po gramu zeolita, a najveće vrijednosti su dobivene uz dodatak 0,06% otopine Humistar®. Pri nižim početnim koncentracijama olova, dodatak otopine Humistar ® udvostručilo je količinu vezanog olova, a porastom koncentracije Humistara ® vrijednosti su se uvećale za tri puta u odnosu na kontrolnu suspenziju. Pri tome nije bilo utjecaja pH vrijednosti na kapacitet vezanja. Najviši stupanj uklanjanja olova je dobiven za niže koncentracije olova i uz veći dodatak Humistara ® . Temeljem dobivenih rezultata može se zaključiti da bi prisutnost organske tvari u tlu mogla povećati učinkovitost uklanjanja pri remedijaciji teških metala primjenom prirodnog zeolita.In this work, the binding of lead ions on the natural zeolite clinoptilolite has been examined in the presence of Humistar ® solution, with high amount of humic acids and other organic compounds simulating the organic matter found in the soil. Experiments have been conducted in solutions with different initial concentrations of lead ions, and the influence of the humic acids on the accuracy of lead determination by the complexometric titration has been examined. The lead ions removal on natural zeolite in solutions of different initial concentrations of lead and different concentrations of Humistar ® solutions have been performed at different pH values. At the higher concentrations of lead ions, higher amount of lead has been removed per gram of zeolite, where the highest values are recorded with addition of 0.06% of the Humistar ® solution. At lower lead concentration the addition of the Humistar ® solution increased removal for double, and increase of the Humistar ® solution concentrations increased removal for triple compared to the control suspension, respectively. The influence of the pH value on removal capacity in all experiments was negligible. The highest removal efficiency has been observed for lower lead concentrations with higher content of the Humistar ® solution. Based on the observed results it can be concluded that appearance of organic matter in the soil might increase removal efficiency during remediation of heavy metals using natural zeolites
The quality of fruits of different fruit species as a medium for the development of the Mediterranean fruit fly Ceratitis capitata wiedemann (diptera, tephritidae) under laboratory conditions : diploma thesis
No full textMediteranska voćna muha Ceratitis capitata Wied. (Diptera, Tephritidae) je štetnik koji se razvija u plodovima velikog broja voćnih vrsta. Cilj istraživanja koja su provedena u laboratorijskim uvjetima bio je utvrditi eventualne razlike u pogodnosti plodova odabranih voćnih vrsta na razvoj ličinki C. capitata. Plodnim ženkama C. capitata je dana mogućnost da u trajanju od 2 dana polažu jaja u plodove istraživanih domaćina u pojedinačnim kavezima. Istraživanja su pokazala da postoje razlike u elementima razvoja kod tri istraživana domaćina: grejp – Citrus paradisi Macfad., mango – Mangifera indica L. i jabuka – Malus domestica L. Prosječne vrijednosti trajanja razvoja ličinki u danima su najkraće u plodovima manga gdje prosječna dužina razvoja traje 15,35-21,1 dan, kod jabuke 31,7-36,1 a kod grejpa 30,6-41,3 dana. Najveći broj ličinki razvio se iz plodova manga (45-51 ličinki), zatim slijede plodovi jabuke (16-19 ličinki), a najmanji broj ličinki se razvio iz plodova grejpa (3-4 ličinke). Najveću težinu su imale kukuljice proizašle iz ličinki koje su se razvile iz plodova manga (8,7 g), a značajno manju iz plodova grejpa (5,5 g) i jabuke (4,8 g). Iz navedenog istraživanja možemo zaključiti da su plodovi manga najkvalitetniji medij za razvoj ličinki C. capitata.Mediterranean fruit fly Ceratitis capitata Wied. (Diptera, Tephritidae) is a pest that develops in the fruits of a large number of fruit species. Studies conducted under laboratory conditions were aimed at determining possible differences in the suitability of fruits of selected fruit species for C. capitata larval development. Fertile females of C. capitata were given the opportunity to lay eggs in individual cages for 2 days in the fruits of the hosts studied. The results showed that there are differences in the elements of development in the three hosts studied: grapefruit - Citrus paradisi Macfad., mango - Mangifera indica L. and apple - Malus domestica L. The average values of the duration of larval development in days are the shortest in mango fruits, where the average duration of development is 15.35-21.1 days, for apples 31.7-36.1 and for grapefruit 30.6-41.3 days. Most larvae developed from mango fruits (45-51 larvae), followed by apple fruits (16-19 larvae) and the fewest number of larvae developed from grapefruit fruits (3-4 larvae). Pupae from larvae developing from mango fruits (8.7 g) had the greatest weight, and significantly less weight from grapefruit (5.5 g) and apple (4.8 g). From the above studies, we can conclude that mango fruits are the best medium for the development of C. capitata larvae