Repository of Faculty of Chemical Engineering and Technology University of Zagreb
Not a member yet
2768 research outputs found
Sort by
Validation of LC-MS/MS method for the determination of N-nitroso-hydrochlorothiazide in hydrochlorothiazide active substance
No full textValidacija je važan korak u stvaranju analitičke metode nakon njenog razvitka, te se validacija definira kao postupak dokazivanja je li metoda prikladna za namjeravanu upotrebu. Validacija analitičke metode izvodi se u laboratoriju provođenjem ispitivanja izvedbenih karakteristika metode kao što su selektivnost/specifičnost, linearnost, preciznost, točnost, granica detekcije i kvantifikacije, radno područje te robusnost. Ovisno o namjeni analitičke metode ne moraju se nužno ispitivati sve izvedbene karakteristike već samo odabrane. Glavni cilj ovog rada bio je potvrditi prikladnost LC-MS/MS metode za određivanje N-nitrozo-hidroklorotiazida u hidroklorotiazid aktivnoj supstanci. Eksperimentalni dio rada izveden je u laboratoriju Odjela Kontrole kvalitete, Pliva Hrvatske d.o.o. ispitivanjem svih potrebnih izvedbenih karakteristika. Postignuta je dobra linearnost (R^2 = 1,000) te su također zadovoljeni kriteriji za preciznost (RSD ≤ 20 %) i točnost (RSD ≤ 25 %). Definirana je granica kvantifikacije (LOQ = 0,60 ng/ml) te radno područje metode (0,60 ng/ml – 50 ng/ml). Dodatno je ispitana stabilnost otopina standarda N-nitrozo-hidroklorotiazida i hidroklorotiazid aktivne supstance i te robusnost metode. Rezultatima validacije potvrđena je prihvatljivost metode za određivanje N-nitrozo-hidroklorotiazida u hidroklorotiazid aktivnoj supstanci što omogućuje njenu primjenu u svakodnevnom rutinskom radu laboratorija.Validation is a key step in the creation of an analytical method after its development, and it is defined as the process of proving whether the method is suitable for the intended purpose. Analytical method validation is conducted in the laboratory by testing performance characteristics of the method, such as selectivity, specificity, linearity, working range, precision, trueness, limit of detection and quantification, and robustness. Depending on the purpose of the analytical method, it is not necessary to examine all performance features, but only selected ones. The main goal of this work is to validate the LC-MS/MS method for the determination of N-nitroso-hydrochlorothiazide in hydrochlorothiazide active substance. The experimental part of the work covered determination of all performance characteristics and was conducted in the Quality Control Department, Pliva Croatia d.o.o. The method achieved good linearity (R^2=1,000) and met the criteria for precision (RSD ≤ 20%) and accuracy (RSD ≤ 25%). The limit of quantification (LOQ = 0,60 ng/ml) as well as the working range of the method (0,60 ng/ml – 50 ng/ml) are defined. In addition, the stability of the solutions of N-nitroso-hydrochlorothiazide standard and hydrochlorothiazide active substance and the robustness of the method were evaluated. The validation results confirmed the acceptability of the method for the determination of N-nitroso-hydrochlorothiazide in hydrochlorothiazide active substance was confirmed, given that the obtained values of performance characteristics are within the given limits of acceptability. This enables the application of the method in the daily routine work of the laboratory
Removal of the cyanide and the rhodanide from waters
No full textCijanidi i rodanidi su toksični spojevi sa štetnim utjecajem na okoliš i ljudsko zdravlje. Cijanidi su poznati kao bitna sirovina kod proizvodnje farmaceutika, kozmetike, medicinskih i poljoprivrednih proizvoda te kod procesa obrade u metalurškoj industriji. Reakcijama cijanida sa sumporom nastaju rodanidi ili tiocijanati koji su karakterizirani kao spojevi manje toksičnosti, ali veće stabilnosti od cijanida. Razvojem industrije i povećavanjem proizvodnih kapaciteta raste i količina otpadnog cijanida točnije otpadnim vodama dospjevaju u okoliš. Stoga je potrebno provoditi obradu otpadnih voda prije ispuštanja iz postrojenja kako bi se smanjila njihova prisutnost u okolišu. Napredni oksidacijski procesi su vrsta procesa koji se koriste pri obradi takvih onečišćenih voda. Temelje se na korištenju oksidacijskih sredstava pomoću kojih dolazi do uspješne razgradnje i uklanjanja neželjenih organskih spojeva.
U ovom radu provedena su istraživanja uklanjanja cijanida (CN-) i tiocijanata (SCN-) iz modelnih otopina naprednim oksidacijskim procesima fotolizom, UV/H2O2 i UV/S2O82- pri pH vrijednostima 4, 7 i 10. Omjer onečišćivala (CN- i SCN-) prema oksidacijskom sredstvu (H2O2 i S2O82-) iznosio je 1:10 dok je valna duljina UV zračenja iznosila 254 nm. Rezultati su pokazali kako je najučinkovitija primjena UV/S2O82- za oba istraživana onečišćivala pri nižim pH. Metoda UV/S2O82- je najučinkovitija s 99,26% uklonjenog CN- i 80,26% uklonjenog SCN- pri pH = 4. Minimalne učinkovitosti pri uklanjanju oba onečišćivala zabilježene su kod čiste fotolize gdje je uklonjeno samo 40,90% CN- (pH = 7) i 21,49% SCN- (pH = 10). Najbrža je kinetika razgradnje CN- metodom UV/S2O82- (k = 0,0806 s^-1) pri pH=4 dok je najsporija tijekom čiste fotolize (k = 0,0076 s^-1) pri pH=7. Najbrža razgradnja SCN- je metodom UV/S2O82- (k =0,027 s^-1) pri pH=4 dok je najsporija tijekom čiste fotolize (k = 0,0041 s^-1) pri pH = 10. Navedene brzine uklanjanja CN- i SCN- su prvog reda odnosno kinetika se ipak smatra pseudo-prvog reda zbog velikog broj radikalskih reakcija.Cyanides and rhodanides are toxic compounds with a negative influence on the environment and the human health. Cyanides are known as a important raw material in pharmaceutical, cosmetics, medical and agricultural product manufacture and in processing processes of the metallurgical industry. Reactions between cyanides and sulphur result with the formation of rhodanides or thiocyanites which are charaterized as compunds with lower toxicity but higher stability than cyanides. With the development of the industry and the increase in production capacity, the amount of cyanide and rhodanides that ends up in the environment within wastewaters increases. Because of that, it is necessary to carry out the wastewater treatment before the discharging to decrease their presence in the environment. Advanced oxidation processes are a type of processes which are used for treating that kind of polluted water. They are based on the usage of oxidizing agents which successfully result with the decomposition of unwanted organic compounds. This work deals with the removal od cyanides (CN-) and rhodanides (SCN-) from model solutions by the advanced oxidation processes using photolysis, UV/H2O2 and UV/S2O82- at pH values 4, 7 and 10. The ratio of pollutants (CN- and SCN-) to oxidizing agents (H2O2 and S2O82-) was 1:10, while the wavelength of the UV radiation was 254 nm The results showed that the usage of the UV/S2O82- method under lower pH values was the most effient for both pollutants. The UV/S2O82- method is the most efficient with 99.26% of CN- and 80.26% of SCN- removed at pH=4. Minimal efficiencies in the removal of both pollutants were recorded with pure photolysis, where only 40.90% of CN- (pH=7) and 21.49% of SCN- (pH=10) were removed. The fastest kinetics of the CN- degradation is by the UV/S2O82- method (k = 0.0806 s^-1) at pH=4, while the slowest is during pure photolysis (k = 0.0076 s^-1) at pH=7. The fastest degradation of SCN- is by the UV/S2O82- method (k = 0.027 s^-1) at pH=4, while the slowest is during pure photolysis (k = 0.0041 s^-1) at pH=10. The stated removal processes of CN- and SCN- contain first order reactions, that are actually considered to be pseudo-first order due to the large number of radical reactions
Assessment of physico-chemical properties of insulating oils by molecular spectroscopy techniques with use of chemometric methods and artificial neural networks
No full textU ovom doktorskom radu izrađeni su računski modeli za procjenu fizikalno-kemijskih svojstava mineralnih izolacijskih ulja iz podataka dobivenih tehnikama molekulske spektroskopije. Cilj disertacije je izrada visoko pouzdanih računskih modela za procjenu fizikalno-kemijskih svojstva ulja čime bi se iz molekulskih spektara dobio podatak o starenju ulja i prisutnim kemijskim onečišćenjima. Uz izradu modela, tijekom disertacije istraženi su međuodnosi fizikalno-kemijskih svojstava ulja kako bi se doprinijelo shvaćanju informacija koje se dobivaju njihovim ispitivanjem. Iz dobivenih molekulskih spektara provedene su analize značajnih područja spektara, određivanje signala koji se u spektrima mijenjaju s promjenama fizikalno-kemijskih svojstava, te identifikacija odgovornih kemijskih vrsta. Pripremljen je velik broj uzoraka (1135 uzoraka) izolacijskih ulja u različitim fazama ostarjelosti. Dio uzoraka sačinjavala su potpuno nova ulja različitih kemijskih sastava, dio uzoraka pripremljen je iz novih ulja metodom ubrzanog starenja na povišenoj temperaturi u oksidacijskim uvjetima, a dio uzoraka sačinjavali su realni uzorci iz elektroenergetske opreme u pogonu. Svim uzorcima ulja ispitana su fizikalno-kemijska svojstva (boja, kiselost, granična površinska napetost na granici voda-ulje, gustoća, faktor dielektričnih gubitaka i električni otpor) te su izmjereni molekulski spektri određenih uzoraka (infracrveni, ultraljubičasto-vidljivi i Ramanovi spektri). Pomoću izmjerenih fizikalno-kemijskih svojstava ulja izrađene su krivulje međusobne korelacije između različitih svojstava. Istražene su međuovisnosti svojstava koja su indikatori kemijskog sastava ulja, međuovisnosti svojstava koja su indikatori ostarjelosti ulja, te ovisnosti između svojstava koja opisuju kemijski sastav i ostarjelost ulja. Pošto se molekulski spektri uzoraka sastoje od vrlo velikog broja podataka koje imaju različito značenje, a opisuju vibracije kemijskih veza i elektronske prijelaze u molekulama, određena je važnost dijelova spektara za procjenu svakog pojedinog fizikalno-kemijskog svojstva izolacijskih ulja pomoću metode koeficijenata važnosti varijabli u projekciji i metode omjera selektivnosti. Također, izrađeni su regresijski modeli za procjenu fizikalno-kemijskih svojstava ulja metodom parcijalnih najmanjih kvadrata i umjetnim neuronskim mrežama. Iz infracrvenih spektara dobiveni su računski modeli koji s vrlo visokom pouzdanošću koja je unutar propisanih granica ponovljivosti mjerenja normiranim metodama procjenjuju boju, kiselost, graničnu površinsku napetost na granici voda-ulje i gustoću mineralnih izolacijskih ulja. Iz visoke koreliranosti kiselosti, boje i granične površinske napetosti ulja s karbonilnom spektralnom vrpcom, zaključeno je kako su za promjenu svojstava izolacijskih ulja tijekom starenja najodgovorniji karbonilni spojevi, točnije karboksilne kiseline, aldehidi i ketoni. Za okom vidljivu promjenu boje izolacijskih ulja tijekom starenja najodgovorniji su kinoni, koji su ciklički nezasićeni ketoni. Gustoća, koja ponajprije ovisi o kemijskom sastavu ulja pokazuje najveću korelaciju s vibracijskim vrpcama koje opisuju ugljikovodični sastav ulja, točnije s karakterističnim vibracijama alkana i alkena te intenzivnim vrpcama C–H rastezanja pri višim valnim brojevima. Granična površinska napetost ulja jedino je svojstvo koje pokazuje visoku ovisnost i o kemijskom sastavu i o ostarjelosti ulja. Modeli procjene faktora dielektričnih gubitaka i električnog otpora ulja iz infracrvenih spektara nisu bili uspješni, a razlog tome pronađen je u nemogućnosti kvantifikacije kemijskih spojeva koji doprinose tim svojstvima (mikrometarske čestice metalne i polimerne prirode te čađa i voda) pomoću infracrvenih spektara. Iz ultraljubičasto-vidljivih spektara dobiven je računski model koji s vrlo visokom pouzdanošću procjenjuje boju ulja. Boju ulja je moguće procijeniti radi obojenosti kinona koji nastaju tijekom starenja ulja te apsorbiraju i u infracrvenom i u ultraljubičasto-vidljivom spektru. Druga fizikalno-kemijska svojstva ulja nije bilo moguće pouzdano procijeniti iz ovih spektara radi nemogućnosti praćenja sadržaja karbonilnih spojeva i ugljikovodičnog sastava ulja u ultraljubičasto-vidljivim spektrima. Ramanovi spektri pokazali su se neupotrebljivima za izradu računskih modela radi vrlo niskih signala, visoke razine šuma prilikom mjerenja, te pojave luminiscencije koja kod ostarjelih uzoraka prekriva signale. Moguće je kako bi korištenje Ramanovih spektrometara drugačije konfiguracije i različitih laserskih izvora dalo bolje podatke. Rezultati prikazani u ovom doktorskom radu ukazuju na velike mogućnosti primjene spektroskopskih metoda procjene za dopunu postojećih laboratorijskih metoda mjerenja, kao i za izradu jednostavnijih mjernih uređaja koji bi na terenu ili tijekom rada opreme mogli pratiti fizikalno-kemijska svojstva i stanje izolacijskih ulja.In this doctoral thesis, computational models for the assessment of physico-chemical properties of mineral insulating oils based on data collected using molecular spectroscopy techniques were developed. The goal of this thesis was to develop computational models which will predict physico-chemical properties of oils from their molecular spectra with a high level of confidence, and through which information is provided on oil ageing and any chemical impurities present. Along with model development, the relationships between physico-chemical properties of oils were investigated to contribute to a better understanding of information provided by the tests. Analyses of significant spectral regions in molecular spectra were performed, signals which vary with changes in physico-chemical properties were determined, and the responsible chemical species were identified. Many samples (1135 samples) of insulating oils of different ageing levels were prepared. Part of the samples consisted of completely new oils of different chemical composition, another part was prepared from new oils through a method of accelerated ageing at elevated temperatures and under oxidizing conditions, and the last part consisted of real samples from electrical equipment in operation. Physico-chemical properties were tested on all the samples (colour, acidity, interfacial tension at the oil-water interface, density, dielectric dissipation factor, and specific resistivity) and molecular spectra were measured for specific samples (infrared, ultraviolet-visible, and Raman spectra). Based on the measured physico-chemical properties, correlation curves were made between different properties. Relationships were investigated between properties that are indicators of the chemical composition of oils, between properties which are indicators of oil ageing, as well as interdependences between properties which describe oil composition and oil ageing. Since molecular spectra consist of a very large number of data points that have different chemical meanings and describe chemical bond vibrations and molecular electronic transitions, the significances of spectral regions for the assessment of each individual physico-chemical property of insulating oils were determined using the variable importance in projection method and the selectivity ratio method. With the known significances of spectral regions, regression models were developed for the assessment of physico-chemical properties of oils using partial least squares regression modelling as well as artificial neural network modelling. Infrared spectra were used to develop models which, with a very high degree of confidence, which is within the repeatability criteria of standardised methods, predict the colour, acidity, interfacial tension at the water-oil interface and density of mineral insulating oils. The acidity, colour, and interfacial tension of the oil correlated highly with the carbonyl spectral band, and it was concluded that carbonyl compounds, more specifically carboxylic acids, aldehydes, and ketones are responsible for the changes in properties of insulating liquids during ageing. Changes in colour of insulating liquids are visible to the naked eye, and the compounds responsible are quinones, which are cyclic unsaturated ketones. Density, which first and foremost depends on the chemical composition of the oil, shows the greatest correlation with vibration bands which describe the hydrocarbon composition of the oil, more precisely the characteristic vibrations where alkanes and alkenes can be detected, as well as the intense C–H stretches at higher wavenumbers. The interfacial tension of oil is the only property which shows a high degree of dependence on both chemical composition and oil ageing. Assessment models for dielectric dissipation factor and specific resistivity of oils from infrared spectra were not successful, and the reason was impossibility of quantification of chemical compounds which contribute to those properties (micrometre size particles of metals and polymers, carbon black, and water) with infrared spectra. Based on ultraviolet-visible spectra, a computational model which estimates the colour of insulating liquids with a very high level of confidence was developed. The colour of oil can be predicted due to the coloured nature of quinones formed during oil ageing, which absorb in both infrared and ultraviolet-visible spectra. It was not possible to estimate other physico-chemical properties from these spectra due to the impossibility of monitoring the content of carbonyl compounds and the hydrocarbon composition of oils with ultraviolet-visible spectra. Raman spectra were unusable for computational model development due to very low signal strength, high levels of noise during measurement, and the appearance of luminescence which masks signals in aged samples. It is possible that the use of differently configured Raman spectrometers and other laser sources would provide better data. The results presented in this thesis imply the possibility of using spectroscopic assessment methods in supplementing the existing laboratory measurement methods, as well as in the development of simple measurement devices which could monitor the physico-chemical properties of insulating oils in the field or during equipment operation
Collagen coating for bioactivation of the titanium implant surface
No full textMetalni materijali, posebice titanij i njegove legure, pripadaju grupi najčešće korištenih materijala za izradu implantata. Iako posjeduju dobra mehanička i biokompatibilna svojstva, ubrajaju se u bioinertne materijale. Ugradnja titanijevog implantata u ljudsko tijelo ne potiče značajne biološke reakcije, tj. stanične procese potrebne za interakciju površine implantata s biološkim tkivima i poticanje rasta tkiva, odnosno oseointegraciju. Stoga je u ovom radu provedena funkcionalizacija površine titanija prevlakom kolagena, koji je ključni strukturni protein s važnom ulogom u strukturi kostiju i regeneraciji tkiva. Funkcionalizacija kolagenskom prevlakom provedena je s ciljem bioaktivacije površine titanijevog implantata, u svrhu poboljšanja njegove biokompatibilnosti, osteokonduktivnosti i oseointegracije. Nemodificirani uzorci titanija, sa spontano formiranim oksidnim slojem titanijevog (IV) oksida, i uzorci modificirani kolagenskom prevlakom, uronjeni su u otopinu Fusayama umjetne sline tijekom 16 tjedana. Bioaktivnost kolagenske prevlake utvrđena je promatranjem spontanog formiranja depozita kalcijevih fosfata na površini uzoraka uslijed urona. Morfologija, mikrostruktura i kemijski sastav supstrata prije i nakon uranjanja u otopinu umjetne sline karakterizirani su pretražnom elektronskom mikroskopijom (SEM), energijski razlučujućom rendgenskom spektrometrijom (EDS) i infracrvenom spektroskopijom s Fourierovom transformacijom uz prigušenu totalnu refleksiju (ATR-FTIR). Elektrokemijsko ponašanje uzoraka ispitano je metodom elektrokemijske impedancijske spektroskopije (EIS) u otopini umjetne sline koja simulira stvarne uvjete primjene implantata.Metal materials, especially titanium and its alloys, belong to a group of the most commonly used materials for producing implants. Even though they possess good mechanical and biocompatible properties, they are referred to as bioinert materials. The implantation of a titanium implant into the human body does not encourage significant biological reactions, such as the cellular processes needed for interaction between the surface of the implant and biological tissue and for stimulating the growth of tissue, known as osseointegration. Therefore, in this work, the functionalization of the titanium surface with a collagen coating was conducted. Collagen is an essential structural protein with a major role in bone construction and tissue regeneration. The functionalization with the collagen coating was carried out with the purpose of bioactivating the titanium implant surface to improve its biocompatibility, osteoconductivity, and osseointegration. Unmodified titanium samples, with a spontaneously formed oxide layer of titanium (IV) oxide, and samples modified with a collagen coating were immersed in Fusayama artificial saliva solution for 16 weeks.
The bioactivity of the collagen coating was established by monitoring the spontaneous formation of calcium phosphate deposits on the sample surface after immersion. Morphology, microstructure, and chemical composition of the substrate before and after immersion into the artificial saliva solution were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and attenuated total reflectance using Fourier transform infrared spectroscopy (ATR-FTIR). The electrochemical behavior of the samples was examined using electrochemical impedance spectroscopy (EIS) in artificial saliva solution, which simulates real-life conditions of implant application
Mathematical model development for ATP synthesis in a cascade reaction
No full textAdenozin trifosfat (ATP) ima veliku ulogu u skladištenju energije koja je potrebna za odvijanje bioloških procesa u živim stanicama – sinteze, transporta, mobilnosti molekula i sl. Energija se skladišti u vezama među fosfatnim skupinama, a strukturu molekule ATP-a čini lanac od tri fosfatne skupine uz D-ribozu i adenin. Njegova upotreba porasla je primjenom izvanstaničnih enzimskih procesa u raznim industrijskim svrhama poput proizvodnje lijekova, vitamina, hrane, tekstila i dr. Zbog visoke cijene i česte primjene sve veća pažnja posvećena je razvijanju novih puteva njegove regeneracije. U ovom radu opisan je proces sinteze ATP-a iz adenozina i adenozin monofosfata (AMP) linearnom kaskadnom reakcijom uz upotrebu enzima ADK, PPK2-I te PPK2-II. Eksperiment je proveden upotrebom matematičkog modeliranja i genetskog algoritma uz računalne programe SCIENTIST i GALOP (engl. Genetic Algorithm for the Optimization of Processes). U SCIENTIST-u je provedena simulacija sinteze ATP-a, dok je pomoću GALOP- -a provedena optimizacija početnih uvjeta procesa – koncentracije adenozina, AMP-a, magnezijevih iona te vrijeme trajanja reakcije. Vrijednosti koncentracija enzima i polifosfata održavane su konstantnima. Cilj rada pronalazak je optimalnih uvjeta procesa pri kojima je moguće postići maksimalnu koncentraciju ATP-a. Dobiveni rezultati pokazali su kako je pri optimalnim uvjetima moguće postići koncentraciju ATP-a od 20,7 mM.Adenosine triphosphate (ATP) plays a significant role in storing the energy required for biological processes in living cells – synthesis, transport, mobility of molecules and more. The energy is stored in the bonds between phosphate groups, and the structure of the ATP molecule consists of a chain of three phosphate groups along with D-ribose and adenine. The necessity for ATP has increased with the application of extracellular enzymatic processes for different industrial purposes, such as production of drugs, vitamins, food, textiles and others. Due to its high cost and frequent usage, increasing attention has been focused on developing novel pathways for its regeneration. This paper describes the process of ATP synthesis from adenosine and adenosine monophosphate (AMP) through a linear cascade reaction using the enzymes ADK, PPK2-I, PPK2-II. The experiment was conducted using mathematical modeling and genetic algorithm with computer programs SCIENTIST and GALOP (Genetic Algorithm for the Optimization of Processes). In SCIENTIST, a simulation of ATP synthesis was conducted, while GALOP was used to optimize the initial conditions of process – concentration of adenosine, AMP, magnesium ions and reaction duration. The concentrations of enzymes and polyphosphate were kept constant. The aim of this study was to find the optimal process conditions to achieve the maximum concentration of ATP. The results obtained showed that, under optimal conditions, it is possible to achieve an ATP concentration of 20,7 mM
Sophorolipids purification
No full textSoforolipidi su prirodni biosurfaktanti koje sintetizira kvasac Candida koji koristi šećer i biljno ulje kao izvore nutrijenata za rast. Ovi spojevi imaju značajan potencijal za primjenu u industriji zbog svojih biorazgradivih svojstava i sposobnosti stvaranja stabilnih emulzija.
U ovom istraživanju provedena je modifikacija soforolipida u enzimski kataliziranoj reakciji te pročišćavanje dobivene reakcijske smjese. Nakon provedenog pročišćavanja svaka dobivena frakcija podvrgnuta je analizi na HPLC uređaju kako bi se precizno odredio sastav i čistoća produkata. Tijekom procesa pročišćavanja, izolirani su produkti s različitim brojem monosaharidnih jedinica, pri čemu je posebna pažnja posvećena izolaciji i analizi produkta n=1, koji predstavlja specifični cilj ovog istraživanja. Kao nusprodukti reakcije, formirani su i oligosaharidi, koji su uspješno uklonjeni iz reakcijske smjese pomoću etanola.
Ovo istraživanje pruža važne uvide u proces enzimske modifikacije soforolipida i njihovu potencijalnu primjenu u raznim industrijskim sektorima.Sophorolipids are natural biosurfactants synthesized by the Candida yeast that uses sugar and vegetable oil as sources of nutrients for growth. These compounds have significant potential for application in industry due to their biodegradable properties and ability to form stable emulsions. In this research, the modification of sophorolipids in an enzyme-catalyzed reaction and the purification of the resulting reaction mixture was carried out.
After purification, each obtained fraction was subjected to analysis on an HPLC device in order to precisely determine the composition and purity of the product. During the purification process, products with different numbers of monosaccharide units were isolated, whereby special attention was paid to the isolation and analysis of products n=1, which represents the specific goal of this research. As byproducts of the reaction, oligosaccharides were also formed, which were successfully removed from the reaction mixture using ethanol. This research provides important insights into the process of enzymatic modification of sophorolipids and their potential application in various industrial sectors
Wastewater and environment
No full textOnečišćenje vodenih sustava otpadnim vodama je istaknuti problem koji izaziva veliku zabrinutost. S porastom svjetske populacije raste i količina otpadnih voda koju je potrebno učinkovito obraditi. Značajne količine otpadnih voda se ispuštaju u vodeni okoliš, stvarajući ozbiljne prijetnje za ekosustave i dobrobit ljudskog zdravlja. Kako bi se spriječilo daljnje onečišćenje, iznimno je važno razumijevanje sastava otpadnih voda čime se omogućuje njihova ciljana obrada i povećava učinkovitost samog procesa. U okviru završnog rada dan je pregled izvora i vrsta otpadnih voda, postupci obrade otpadnih voda s naglaskom na industrijske otpadne vode iz farmaceutske proizvodnje.The pollution of water systems by wastewater is a major problem that gives cause for great concern. As the world's population grows, so does the amount of wastewater that needs to be treated effectively. Significant amounts of wastewater are being discharged into water bodies, posing a serious threat to ecosystems and human health. To prevent further pollution, it is extremely important to understand the composition of wastewater, treat it in a targeted manner, and increase the efficiency of the process. The thesis provided an overview of the sources and types of wastewater, and wastewater treatment processes with a focus on industrial wastewater from pharmaceutical production
Electrochemical deposition of collagen coating for dental implants
No full textJedan od ključnih izazova suvremene dentalne medicine je razvoj implantata koji učinkovito imitiraju strukturu i funkciju prirodne kosti, čime se osiguravaju dugoročna stabilnost implantata i očuvanje zdravlja okolnog koštanog tkiva. Titanij i njegove legure najčešće se koriste u izradi dentalnih implantata zbog svoje izvrsne mehaničke otpornosti i biokompatibilnosti. Ipak, za uspješnu oseointegraciju nije dovoljan samo materijal – presudnu ulogu ima i površinska modifikacija koja može poboljšati zaštitnu djelotvornost i bioaktivnost implantata. Cilj ovog rada bio je modificirati površinu Ti pločica kolagenskom prevlakom dobivenom kemijskim i elektrokemijskim metodama, s ciljem poboljšanja zaštitne djelotvornosti i bioaktivnosti titanija. Kolagen, kao najzastupljeniji protein ljudskog tijela, primijenjen je kako bi povećao zaštitnu djelotvornost te potaknuo stvaranje kalcij-fosfatnih naslaga (CaP) i ubrzao oseointegraciju. Za ispitivanje zaštitne djelotvornosti i bioaktivnosti uzoraka korištene su metode pretražna elektronska mikroskopija uz energijski razlučujuću rendgensku spektrometriju (SEM/EDS), infracrvena spektroskopija s Fourierovom transformacijom uz prigušenu totalnu refleksiju (ATR-FTIR), rendgenska difrakcija (XRD) i ciklička voltametrija (CV). Bioaktivnost je određena nakon sedmodnevnog uranjanja uzoraka u otopinu umjetne sline. Rezultati su pokazali da kolagenske prevlake, osobito one dobivene elektrokemijskim postupkom s 20 ciklusa, doprinose formiranju CaP naslaga te smanjuju gustoću struje, čime poboljšavaju i bioaktivnost i zaštitnu djelotvornost. Zbog toga su titanijeve površine modificirane kolagenom pokazale značajan potencijal za primjenu u dentalnoj implantologiji.One of the key challenges in modern dental medicine is the development of implants that effectively mimic the structure and function of natural bone, thereby ensuring the long-term implant stability and the preservation of the surrounding bone tissue. Titanium and its alloys are the most commonly used in the fabrication of dental implants due to their excellent mechanical strength and biocompatibility. However, successful osseointegration requires more than just the choice of material — surface modification plays a crucial role in enhancing both the protective performance and bioactivity of the implant. The aim of this study was to modify the surface of titanium plates with a collagen coating obtained by chemical and electrochemical methods, in order to improve their protective effectiveness and bioactivity. Collagen, the most abundant protein in the human body, was applied to enhance surface protection, promote the formation of calcium-phosphate (CaP) deposits, and accelerate osseointegration. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), attenuated total reflection – Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and cyclic voltammetry (CV) were used to assess the protective performance and bioactivity of the samples. Bioactivity was evaluated after a seven-day immersion of the samples in artificial saliva. The results showed that the collagen coatings, particularly those obtained through the electrochemical process with 20 cycles, contributed to the formation of CaP deposits and reduced the current density, thereby improving both bioactivity and protective effectiveness. Collagen-modified surfaces demonstrated significant potential for application in dental implantology
Enzymatic synthesis of hydroxycinnamic acid amide in aqueous medium
No full textBiokemijske reakcije sastavni su dio svih živih bića te zahtijevaju veću brzinu od klasičnih kemijskih reakcija radi održavanja normalnog tijeka životnih funkcija. Enzimi su ključni elementi provedbe biokatalize jer povećavaju brzinu reakcija za iznos od najmanje 106 te uvelike olakšavaju sintezu i industrijsku proizvodnju tvari čije je dobivanje klasičnom kemijskom sintezom znatno teže. Zahtijevaju specifične uvjete u kojima djeluju, a prisutni su samostalni ili zadržani u cijelim stanicama i mikroorganizmima. U organizmu sudjeluju u regulaciji homeostaze radi pravilnog rada metabolizma, opskrbe energijom te tvorbe proteina, stanica i tkiva. U ovom radu proučavani su uvjeti provedbe enzimske sinteze amida hidroksicimetne kiseline u vodenom mediju s ciljem određivanja optimalnih uvjeta za provođenje željene reakcije i dobivanje željenog produkta, N-trans-feruloiltiramina.
Produkt reakcije pripada skupini amida hidroksicimetne kiseline, koji svoju ulogu pronalaze u pravilnom funkcioniranju biljaka, a primjenu u mnogim industrijama zbog privlačnih antioksidativnih, antikancerogenih i antiupalnih svojstava. Praćena je aktivnost enzima na spektrofotometru i tekućinskom kromatografu visoke djelotvornosti te je određen utjecaj
pH vrijednosti, temperature i dodatka askorbinske kiseline na aktivnost enzima.Biochemical reactions are an integral part of all living organisms and require a higher reaction rate than classical chemical reactions to maintain the normal course of life functions. Enzymes are key elements in the implementation of biocatalysis because they increase the rate of reactions by at least 106 times and greatly facilitate the synthesis and industrial production of substances whose acquisition is significantly more difficult through classical chemical synthesis. They require specific conditions in which they can operate and are present either independently or retained in whole cells and microorganisms. In the organism, they participate in the regulation of homeostasis for the proper functioning of metabolism, energy supply and the formation of proteins, cells and tissue. In this work, the conditions for the enzymatic synthesis of hydroxycinnamic acid amide in an aqueous medium were studied with the aim of determining the optimal conditions for conducting the desired reaction and obtaining the desired product, N-trans-feruloyltyramine. The reaction product belongs to the group of hydroxycinnamic acid amides, which play a role in the proper functioning of plants and have applications in many industries due to their attractive antioxidant, anticancer and anti-inflammatory properties. The enzyme activity was monitored using a spectrophotometer and high-performance liquid chromatography. The influence of pH value, temperature and the addition of ascorbic acid on enzyme activity was determined
Synthesis of novel biosurfactants
No full textEnzimi i biokataliza su vrlo značajni u suvremenoj kemiji jer omogućuju selektivne i ekološki prihvatljive reakcije. Enzimi, kao biokatalizatori, osiguravaju učinkovitiju i održiviju sintezu brojnih kemijskih spojeva, uključujući biosurfaktante. Biosurfaktanti su amfifilni spojevi koji su površinski aktivni, a u usporedbi s kemijski sintetiziranim surfaktantima, posjeduju veću biorazgradivost, manju toksičnost, specifičnost i sposobnost djelovanja u ekstremnim uvjetima. Zbog svojih jedinstvenih svojstava i ekoloških prednosti, biosurfaktanti pronalaze široku primjenu u različitim industrijama te predstavljaju alternativu konvencionalnim surfaktantima. Ovaj diplomski rad istražuje sintezu novih biosurfaktanata – soforolipida. Cilj istraživanja bio je usavršiti postupak enzimske modifikacije soforolipida u različitim vrstama reaktora te zaključiti koji reaktor je najprikladniji za provođenje reakcije. U eksperimentalnom dijelu provedene su reakcije u tri različita tipa reaktora. Ispitani su šaržni reaktor, reaktor s dotokom supstrata i enzimski membranski reaktor, pri čemu su korištene HPLC-UV/VIS i RI analize za praćenje koncentracije supstrata i produkata. Rezultati su pokazali da je šaržni reaktor najprikladniji za enzimsku modifikaciju soforolipida, omogućujući najbolje uvjete za postizanje najveće konverzije supstrata i iskorištenja.Enzymes and biocatalysis are highly significant in modern chemistry as they enable selective and environmentally friendly reactions. Enzymes, as biocatalysts, provide a more efficient and sustainable synthesis of numerous chemical compounds, including biosurfactants. Biosurfactants are amphiphilic compounds with surface-active properties, and compared to chemically synthesized surfactants, they exhibit higher biodegradability, lower toxicity, specificity, and the ability to function under extreme conditions. Due to their unique properties and environmental benefits, biosurfactants find broad applications in various industries and represent an alternative to conventional surfactants. This master’s thesis explores the synthesis of new biosurfactants – sophorolipids. The aim of the research was to optimize the process of enzymatic modification of sophorolipids in different types of reactors and to determine which reactor is the most suitable for carrying out the reaction. In the experimental section, reactions were conducted in three different types of reactors. A batch reactor, a fed-batch reactor, and an enzymatic membrane reactor were examined, using HPLC-UV/VIS and RI analyses to monitor the concentration of substrates and products. The results showed that the batch reactor is the most suitable for the enzymatic modification of sophorolipids, providing the best conditions for achieving the highest substrate conversion and product yield