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Synthesis of functional derivatives of 1,8-naphtalimide
No full textU okviru ovoga završnog rada opisan je pokušaj priprave naftalimidnog derivata, spoja (2) s ciljem njegove primjene u detekciji sumporovodika (H2S). Za pripravu ciljnog spoja (2) predložen je sintetski put koji se sastoji od dva sintetska koraka. Kao polazni spoj korišten je 4-brom-1,8-naftalanhidrid. Prvi reakcijski korak podrazumijevao je uvođenje azidne skupine u osnovnu naftalanhidridnu strukturu, odnosno pripravu spoja 1, kao receptora odgovornog za prepoznavanje analita (H2S). Spoj 1 uspješno je pripravljen reakcijom 4-brom-1,8-naftalanhidrida i natrijeva azida (NaN3) u suhom dimetilformamidu (DMF). Struktura spoja pretpostavljena je FTIR spektroskopijom. S ciljem priprave odgovarajućeg naftalimidnog derivata, spoja 2, spoj 1 podvrgnut je adicijskog-eliminacijskoj reakciji s dodecilaminom u etanolu kao otapalu zagrijavanjem uz povratno hladilo. Dobivenu smjesu produkata pokušalo se razdvojiti kromatografijom na stupcu uz sustav otapala etil-acetat/heksan, 1:1. Kromatografijom na stupcu razdvojene su dvije glavne frakcije koje fluoresciraju pod UV lampom (365 nm) žutom i plavom bojom. Na temelju IR spektroskopije zaključeno je kako niti jedna od razdvojenih frakcija ne odgovara planiranoj strukturi spoja 2.In this thesis, we describe an experiment to prepare a naphthalimide derivative, a compound of formula (2), to detect hydrogen sulfide (H2S). A synthetic route consisting of two synthetic steps has been proposed for the preparation of the target compound (2). 4-bromo-1,8-naphthalene anhydride was used as the starting compound. The first reaction step was the introduction of an azide group into the basic structure of the naphthalene hydride, i.e. the preparation of compound (1) as the receptor responsible for the recognition of the analyte (H2S). Compound (1) was successfully prepared by reacting 4-bromo-1,8-naphthalene anhydride with sodium azide (NaN3) in dry dimethylformamide (DMF). The structure of compound (I) was suggested by FTIR spectroscopy. In order to prepare the corresponding naphthalimide derivative, compound (2), compound (1) was subjected to an addition-elimination reaction in ethanol in solvent under refluxing refrigeration. The resulting product mixture was separated using a 1:1 ethyl acetate/hexane solvent mixture by column chromatography. Column chromatography was used to separate the two main fractions, which showed yellow and blue fluorescence under UV light (365 nm). Based on IR spectroscopy, it was concluded that neither of the separated fractions corresponded to the designed structure of compound 2
Development of the new all-solid-state potentiometric sensor for determination of anionic surfactants
No full textTenzidi su povrbinski aktivne tvari koje smanjuju povrbinsku napetost i u otopinama stvaraju micele. Podskupina tenzida su anionski tenzidi, odnosno amfifilne tvari koje sadrže anionsku skupinu vezanu izravno ili preko intermedijera na dugi lanac ugljikovodika. Anionski tenzidi koriste se u deterdžentima za ib enje i proizvodima za osobnu njegu te zbog toga nerijetko u prevelikim koli inama zavrbavaju u okolibu. Zbog btetnosti za vodeni sustav, vrlo je bitno pratiti njihovu koncentraciju u okolibu. Cilj ovog rada bio je razviti all-solid-state potenciometrijski senzor za određivanje anionskih tenzida koriste i ionski par dimetildioktadecilamonijev tetrafenilborat (DDA-TPB) kao senzorski materijal. Kao metoda koristila se direktna potenciometrija. Membrana all-solid-state senzora izrađena je od senzorskog materijala, plastifikatora i grafita. Pri optimizaciji membrane, ispitani su utjecaj udjela senzorskog materijala i plastifikatora na odziv senzora. Najbolje odzivne karakteristike pokazao je senzor s plastifikatorom o-nitrofenil oktil eterom (o-NPOE) i udjelom senzorskog materijala od 4 % koji je odabran za daljnja mjerenja.Surfactants are surface-active agents that reduce surface tension and create micelles in solutions. A subgroup of surfactants are anionic surfactants, which are amphiphilic substances that contain an anionic group attached directly or through an intermediate to a long hydrocarbon chain. Anionic surfactants are used in cleaning detergents and personal care products, and therefore often end up in excessive amounts in the environment. Because of their harmfulness to the water system, it is very important to monitor their concentration in the environment. The aim of this work was to develop an all-solid-state potentiometric sensor for the determination of anionic surfactants using the dimethyldioctadecylammonium tetraphenylborate (DDA-TPB) ion pair as sensing material. Direct potentiometry was used as the method. The membrane of the allsolid-state sensor was made of sensor material, plasticizer and graphite. When optimizing the membrane, the influence of the content of sensor material and plasticizer was examined. The best response characteristics were obtained using the sensor with o-nitrophenyl octyl ether (o-NPOE) as the plasticizer and a sensor material content of 4%, which was selected for further measurements
Determination of anionic surfactants in commercial systems using a new all-solid-state potentiometric sensor
No full textU ovom radu koribten je novorazvijeni all-solid-state senzor sa vrstom membranom za određivanje anionskih tenzida u komercijalnim sustavima. Membrana norazvijenog senzora se sastoji od ionskog para DDA-TPB (dimetildioktadecilamonijev tetrafenil borat) koji je koribten kao senzorski materijal, te grafita i o-NPOE-a (2-nitrofenil oktil eter) kao plastifikatora. Metoda koribtena u istra~ivanju je potenciometrijska titracija. Ispitana su etiri razli ita titranta (cetilpiridinijev klorid, heksadeciltrimetilamonijev bromid, diizobutil-fenoksietoksi etil-dimetil benzil amonijev klorid i 1,3-didecil-2-metilimidazolijev klorid) koncentracije 4 × 10⁻³ mol L-1, pri emu je kao analit koribtena otopina natrijeva dodecil sulfata. Kao najpogodniji titrant izabran je cetilpiridinijev klorid zbog najve e to nosti i najve eg skoka potencijala u ekvivalentnoj to ki. Primjena novog all-solid-state potenciometrijskog senzora ispitana je određivanjem sadr~aja anionskih tenzida u tri komercijalna proizvoda, a metodom standardnog dodatka ispitana je to nost senzora. Rezultati su pokazali zadovoljavaju u preciznost i to nost prilikom određivanja sadr~aja anionskih tenzida u komercijalnim uzorcima pomo u novog all-solid-state potenciometrijskog senzora kao detektora zavrbne to ke titracije.In this work, a newly developed all-solid-state sensor with a solid membrane was used for the determination of anionic surfactants in commercial systems. The membrane of the newly developed sensor consists of the ion pair DDA-TPB (dimethyldioctadecylammoniumtetraphenylborate), which was used as the sensor material, graphite and o-NPOE (2-nitrophenyl octyl ether) as plasticizer. The method used in the research is potentiometric titration. Four different titrants (cetylpyridinium chloride, hexadecyltrimethylammonium bromide, diisobutylphenoxyethoxy ethyl-dimethyl benzyl ammonium chloride and 1,3-didecyl-2-methylimidazolium chloride) with a concentration of 4 × 10⁻³ mol L-1 were tested, while the analyte was sodium dodecyl sulfate solution. Cetylpyridinium chloride was chosen as the most suitable titrant due to the highest accuracy and the highest potential jump at the equivalent point. The application of the new all-solid-state potentiometric sensor was tested by determining the content of anionic surfactants in three commercial products, and the accuracy of the sensor was tested using the standard addition method. The results showed satisfactory precision and accuracy when determining the content of anionic surfactants in commercial samples using a new all-solid-state potentiometric sensor as a titration endpoint detector
Methods of O-glycosides preparation
No full textUgljikohidrati se ubrajaju među najva~nije biolobke makromolekule, a u prirodi se esto pojavljuju u obliku glikozida. Po kemijskom sastavu, glikozidi su mijebani acetali, naj eb e sastavljeni od be ernog dijela koji je glikozidnom vezom povezan s nebe ernim aglikanskim dijelom na anomernom ugljikovom atomu. Metode njihove sinteze uklju uju uvođenje zabtitnih skupina kako bi se postigla kemoselektivnost reakcije, aktivaciju glikozidnih donora pomo u raznih katalizatora i kona no, nukleofilni napad glikozidnog akceptora. Osim tradicionalnih metoda, u novije vrijeme razvijene su napredne sintetske strategije, poput "one-pot" sinteze i primjene "armed-disarmed" koncepta, koje omogu uju u inkovitiju i br~u sintezu s manjim brojem koraka i boljom kontrolom reakcije u kontekstu isto e produkta i prinosa reakcije. Ove inovacije ne samo da pojednostavljuju sintezu glikozida, ve otvaraju mogu nosti za njihovu biru primjenu. Ovaj rad istra~uje biolobku va~nost O-glikozida i detaljno analizira tradicionalne i suvremene metode njihove sinteze.Carbohydrates are among the most important biological macromolecules, and in nature, they often occur in the form of glycosides. Chemically, glycosides are mixed acetals, typically composed of a sugar unit linked to the non-sugar aglycon moiety via a glycosidic bond through the anomeric center. Methods of their synthesis involve the introduction of protecting groups in order to achieve chemoselectivity in the reaction, activation of glycoside donors using various catalysts, and finally, nucleophilic attack of the glycoside acceptor. In addition to traditional methods, advanced synthetic strategies have been recently developed, such as one-pot synthesis and the armeddisarmed concept, which enabled a more efficient synthesis with fewer synthetic steps and better control of the reaction in the context of product purity and reaction yield. These innovations not only simplify glycoside synthesis but also open the possibility for wider application. This paper explores the biological significance of O-glycosides and provides a detailed analysis of traditional and contemporary methods of their synthesis
Application of molecular modeling and artificial intelligence in the search for new synthetic routes in organic chemistry
No full textRazvojem računalne tehnologije došlo je do otkrića korisnosti njene primjene u mnogim smjerovima znanosti poput farmacije, znanosti materijala, poljoprivrede, pa tako i organske kemije. Tradicionalno laboratorijsko sintetiziranje molekula samo po sebi je dugo i iscrpno, te isto tako može biti financijski zahtjevno, a najveća mana od svega može biti količina sintetiziranog produkta. Za provođenje klasičnih laboratorijskih sinteza potrebno je izvrsno znanje i ekspertiza u području organske kemije. U ovome radu proučava se spajanje molekulskog modeliranja s algoritmima umjetne inteligencije kako bi se kreirali i optimizirali novi sintetski putevi u organskoj kemiji. Informatičari su tehnološkim napretkom kemičarima omogućili kreaciju molekulskog modeliranja na računalu, te uz potporu umjetne inteligencije omogućili predstavljanje novih otkrića u putevima organske sinteze na koja ni sami znanstvenici ne bi pomislili. Nadalje tijekom prikaza samih rezultata računalo s naučenim softverskim programima ima sposobnost prikazivanja i postotka prinosa reakcije. Zahvaljujući ovome kemičari onda mogu odrediti isplati li im se taj sintetski put ili da se podvrgnu traženju novoga, te nakon toga samog potvrđivanje ili negiranje rezultata koji su dani od strane računala. Samo molekularno modeliranje pruža nam uvid u kemijsku strukturu molekule, njena fizikalna i kemijska svojstva, biološku aktivnost, reaktivnost i mnoge druge stvari, dok umjetna inteligencija, posebice pristup pomoću strojnog učenja procjenjuje koji su podaci iz baze visokokvalitetni te sa tim kombinacijama nastavlja daljnji sintetski put. Kombinacijom ovih tehnologija došlo je do značajnog napretka organske sinteze posebno u vidu uštede na vremenu, cijeni, te se kemičari koji rade u laboratoriju ne moraju bojati kakav će biti iznos prinosa reakcije.With the development of computer technology, its usefulness has been discovered in many scientific fields such as pharmacy, materials science, agriculture and organic chemistry. Traditional laboratory synthesis of molecules is by itself long and exhaustive, and can be also financially demanding, with the biggest drawback being the quantity of synthesized product. Conducting classical laboratory syntheses demands exquisite knowledge and expertise in organic chemistry. This paper explores the integration of molecular modeling with artificial intelligence in order to manufacture and optimize new synthetic pathways in organic chemistry. Technological advancements by computer scientists have enabled chemists to perform molecular modeling on computers, and with the support of artificial intelligence, have facilitated the discovery of new synthetic routes that even scientists themselves might not have thought of. Furthermore, during the presentation of results computers with trained software programs have ability to display reaction yield percentages. Thanks to this, chemists can determine whether a synthetic route is worthwhile or if they should continue searching for a new one, followed by the conformation of rejection of the results provided by the computer. Molecular modeling alone provides insight into the chemical structure of molecules, their physical and chemical properties, biological activity, reactivity and many other aspects. In contrast, artificial intelligence, especially machine learning approaches assesses which data from the database are high quality and uses those combinations to further the synthetic pathway. By combining these technologies, there has been a significant progress sin organic synthesis, particularly in terms of saving time and cost, and bench chemists do not need to fear what results will reaction yield give
Changes in the proteome of Yersinia enterocolitica after treatment with quaternary ammonium compounds
No full textBakterija Yersinia enterocolitica, gram-negativni patogen koji se esto prenosi hranom, testirana je s dezinficijensima na bazi kvaternih amonijevih soli. U testiranju su koribtene prethodno sintetizirane kvaterne amonijeve soli s kloridnim anionom kao inhibitori. Promjene u proteomu analizirane su metodama koje koriste gelove i metodama bez gelova. Klju na uloga pripreme uzoraka posebno se isti e u proteoliti koj digestiji. Daljnje analize provedene su teku inskom kromatografijom povezanom sa spektrometrijom masa, a dobiveni podatci odrađeni su putem alata QuickGO i UniProt. Kona na analiza pokazala je razlike u koli inama "up" i "down" reguliranih proteina, omogu uju i uvid u promjene proteoma i klju ne proteina za rast, razvoj i pre~ivljavanje bakterije pod stresom.The bacterium Yersinia enterocolitica, a gram-negative pathogen frequently transmitted through food, was tested with disinfectants based on quaternary ammonium compounds. In the testing, previously synthesized quaternary ammonium compounds with chlorides were used as inhibitors. Proteome changes were analyzed using both gel-based and gel-free methods. The crucial role of sample preparation is particularly highlighted in proteolytic digestion. Further analyses were conducted using liquid chromatography coupled with mass spectrometry, and the obtained data were processed using QuickGO and UniProt tools. The final analysis showed differences in the quantities of up- and down-regulated proteins, providing insight into proteome changes and key proteins involved in the growth, development, and survival of the bacterium under stress
Synthesis of silver(I) and gold(III) complex compounds with bis-quinazoline derivatives
No full textKompleksni spojevi zanimljivi su za istra~ivanje zbog spektra boja koje mogu emitirati, a u danabnje vrijeme sve se vibe istra~uju u farmaceutskoj industriji. Di-kinazolinski derivati su novija skupina spojeva ija se svojstva job ispituju iako je poznato da imaju medicinska svojstva. Cilj rada je sinteza kompleksa iz soli srebra i zlata s di-kinazolinskim derivatom te određivanje njihove strukture. Zavrbni rad obuhva a teorijsku pozadinu kompleksnih spojeva, spojeva srebra i zlata te kinazolina. Također i povijesni pregled otkri a i sinteze prvih kompleksnih spojeva. Opisane su metode dobivanja kompleksa di-kinazolinskog derivata i srebrovih te jedne soli zlata. Spojevi su karakterizirani FT-IR spektroskopijom i TG/DSC analizom.Complex compounds gained popularity due to the color spectrum they can emit, but today, their appeal comes from their applicability in the pharmaceutical industry. Di-quinazoline derivatives are a more recent discovery, and their properties are still being studied, although it is known that they possess medicinal properties. This paper aims to synthesize silver and gold salts using a di-quinazoline derivative and to analyze their structures and properties. The final paper provides a theoretical background on complex compounds, with a specific focus on silver, gold, and quinazoline compounds. Additionally, it includes a historical overview of the discovery and synthesis of the first complex compounds. The methods employed for the synthesis of the di-quinazoline derivative, and its corresponding silver and gold salts are thoroughly described. Compounds are characterized using FT-IR spectroscopy and TG/DSC analysis
Analysis of kidney stones
No full textAnaliza kamenaca klju na je za procjenu pacijenata s kamenom u mokra nom sustavu, poma~u i lije nicima u identificiranju specifi nih uzroka. U analizi se koriste i kemijske i fizikalne metode. Međutim, kemijske metode esto nisu dovoljno precizne za to nu analizu mokra nih kamenaca i mogu propustiti otkriti određene elemente u kamencima. S druge strane, fizikalne metode sve se vibe koriste u laboratorijima s velikim obimom uzoraka. Raznolikost tipova koji se pojavljuju u bubre~nim kamencima zahtijeva detaljan opis kako bi se bolje razumjela njihova formacija. Bubre~ni kamenci uglavnom se sastoje od kalcijeva oksalata, ali esto sadr~e razli ite koli ine fosfata. Kamenci koji se sastoje od kalcijeva oksalata mogu uklju ivati whewellit (kalcijev oksalat monohidrat) i weddellit (kalcijev oksalat dihidrat). Fosfatni kamenci u razli itim postotcima sadr~e apatit (hidroksiapatit), struvit ili brushit. Manji postotak kamenaca sastoji se od mokra ne kiseline (uratni kamenci) ili cistina. Cilj ovog rada je metodama infracrvene spektroskopije rengenske difrakcije i termogravimetrijske analize okarakterizirati sastav 3 bubre~na kamenca.Stone analysis is crucial in the assessment of patients with urinary stones as it helps doctors to identify specific causes. Both chemical and physical methods are used for the analysis. However, chemical methods may not be precise enough to accurately analyse urinary stones and may not detect certain elements in the stones. On the other hand, physical methods are increasingly used in laboratories with large sample volumes. The variety of types that occur in kidney stones requires a detailed description to understand their formation better. Kidney stones are primarily composed of calcium oxalate, but often also contain varying amounts of phosphate. Stones composed of calcium oxalate may contain whewellite (calcium oxalate monohydrate) and weddellite (calcium oxalate dihydrate). Phosphate stones contain apatite (hydroxyapatite), struvite or brushite in varying proportions. A smaller percentage of the stones consist of uric acid (urate stones) or cystine. The aim of this work is to characterise the composition of 3 kidney stones using the methods of infrared spectroscopy, X-ray diffraction and thermogravimetric analysis
Determination of food contaminants using ICP-MS
No full textKontaminanti u hrani su sve tvari koje mogu štetno utjecati na ljudsko zdravlje i na okoliš. S obzirom na prirodu onečišćenja, dijele se na fizikalne, biološke i kemijske. Do zagađenja može doći u svakom dijelu proizvodnje i konzumiranja hrane, od uzgoja stoke ili bilja do pripreme hrane u kuhinji. Najčešći kemijski kontaminanti u hrani su teški metali, skupina elemenata u koju se svrstava olovo, nikal, živa, kadmij, arsen, aluminij i cink. Teško su razgradivi u prirodi i predstavljaju opasnost za ljudsko zdravlje, kao i zdravlje ostalih živih bića u okolišu. Najpouzdanija metoda za određivanje koncentracije teških metala u hrani je spektrometrija masa uz induktivno spregnutu plazmu. Ovom metodom je eksperimentalno određena koncentracija olova, arsena i kadmija u uzorku mrkve. Izmjerena koncentracija arsena u uzorku je manja od 0.01 mg/kg, koncentracija olova iznosi 0.0515 mg/kg, a koncentracija kadmija iznosi 0.0445 mg/kg. Količine navedenih metala u uzorku manje su od najveće dopuštene količine određene zakonom Republike Hrvatske. Konzumiranje mrkve koja je služila kao uzorak je sigurno te ne bi došlo do trovanja teškim metalima.Food contaminants are any substances that can negatively impact human health and the ecosystem. There are three types of contaminants based on the type of pollution - physical, biological and chemical. Contamination may occur in every step of food production or consumption. Most common chemical contaminants are heavy metals. They are a group of elements that consist of lead, nickel, mercury, cadmium, arsenic, aluminum and zinc. Heavy metals are hardly biodegradable and they represent a great danger to human health, as well as health of all other living beings in the environment. The most reliable method for determining an amount of heavy metals present in food is inductively coupled plasma mass spectrometry. Using this method, concentrations of lead, mercury and arsenic were experimentally measured in a carrot sample. Measured concentration of arsenic is less than 0.01 mg/kg, concentration of lead amounted to 0.0515 mg/kg, and concetration of cadmium was 0.0445 mg/kg. Concentration of aforementioned metals is smaller than the highest allowed amount which is regulated by the law of Republic of Croatia. It is safe to consume the carrot which served as a sample and there would be no heavy metal poisoning when eating it
Modified sol-gel synthesis and characterization of nickel doped cerium(IV) oxide
No full textCerij je vrlo reaktivan element koji je sklon reagiranju sa kisikom na zraku formiraju i cerijev(IV) oksid, CeO2. Svojstva cerija usko su povezana sa njegovom elektronskom konfiguracijom [Xe]4f¹5d¹6s², gdje se cerij nalazi ili u Ce3+ ili u Ce4+ stanju, bto utje e na njegovu sposobnost skladibtenja kisika u strukturi cerijevog(IV) oksida. Zbog svojih svojstava, ima sve biru uporabu u podru jima poput magnetizma gdje se koristi kao trajni magnet, dok se u komercijalne svrhe koristi u lakozapaljivim legurama sa ~eljezom (njem. Mischmetall) prisutnim u raznim upalja ima i svjetiljkama. Termi ka stabilnost cerijeva(IV) oksida razlog je primjene u heterogenim katalizatorima gdje se njegova svojstva i termi ka stabilnost mogu dodatno poboljbati dopiranjem s drugim elementima poput mangana, nikla, bakra ili gadolinija. Cerijev(IV) oksid predstavlja ekolobku i jeftiniju alternativu skupljim elementima koji se koriste u katalizatorima poput platine, zlata i dr. U ovom radu prou avan je utjecaj dopiranja cerijeva(IV) oksida niklom na njegova svojstva. Modificiranom sol-gel sintezom, pripravljeno je pet spojeva cerijeva(IV) oksida dopiranih s razli itim udjelima nikla od 16 % do 20 % koji su karakterizirani rendgenskom difrakcijom u prahu i termogravimetrijskom analizom.Cerium is a rare earth element that is highly reactive with a tendency to react with oxygen in the air to form cerium(IV) oxide, CeO2. The properties of cerium are closely related to its electronic configuration [Xe]4f¹5d¹6s², as cerium can exist either in the Ce3+ or the Ce4+ states, affecting its ability to store oxygen in the crystal structure of cerium(IV) oxide. Owing to these properties, cerium has seen increasingly diverse applications in areas such as magnetism where it is used as a permanent magnet, but also in commercial applications where it is found in ignitable alloys paired with iron (De. Mischmetall)which is present in various lighters and lamps. Cerium(IV) oxide is also being used in heterogeneous catalysis, where its thermal stability can be further enhanced via doping with other elements such as manganese, nickel, copper, or gadolinium. Cerium(IV) oxide, being a fairly common element, represents an environmentally friendly and cost-effective alternative to more expensive elements traditionally found in catalysts. In this paper, the effects of doping cerium(IV) oxide with nickel were studied. Five compounds of cerium(IV) oxide doped with varying nickel contents, from 16 % to 20 %, were synthesized using modified sol-gel synthesis and characterized using X-ray powder diffraction, as well as thermogravimetric analysis