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Potentiometric determination of cationic surfactant using home made FIA/SIA system
No full textDanas je moderna analitička kemija nezamisliva bez metoda koje se zasnivaju na analizi injektiranjem u protok (FIA). FIA se definira kao jednostavna, svestrana analitička tehnika za automatske kemijske analize tekućih uzoraka, koja se zasniva na fizikalnoj i kemijskoj analizi dispergirane zone uzorka, formirane injektiranjem uzorka u tok otopine nosioca te detekcijom nastale promjene. Pogodna tehnika kojom se također vrše analize tenzida je potenciometrijska titracija. Naime, kationski tenzidi se titriraju s anionskim, i obrnuto. Korištenjem navedenih tehnika u ovom završnom radu određivale su se kationske površinski aktivne tvari. Površinski aktivne tvari nazivaju se još i tenzidi, po njihovom svojstvu da smanjuju površinsku napetost tekućine. Odnosno, to su bifunkcionalni organski spojevi koji se sastoje od hidrofilnog i hidrofobnog dijela. Najčešće se koriste u sredstvima za čišćenje, omekšavanje te u dekorativnoj kozmetici.Modern analytical chemistry is unimaginable without methods based on flow injection analysis (FIA). FIA can be defined as a simple, versatile analytical technique for the automatic chemical analysis of liquid samples, based on physical and chemical analysis of the dispersed sample zone which is formed by injecting the sample into the carrier stream and detecting the resulting current. Suitable technique that can also perform analysis of surfactants is the potentiometric titration, namely cationic surfactants are titrated with an anionic and vice versa. In the final paper determination of cationic surfactants was performed by using this techniques. Surface active substances are also called the surfactants because of their ability to reduce the surface tension of the liquid, they are bifunctional organic compound consisting of a hydrophilic and hydrophobic part. They are most commonly used in cleaning, softening and in decorative cosmetics
Određivanje naboja i veličine čestica akustičnom spektroskopijom
No full textOvaj rad opisuje metode određivanja veličine i naboja čestica u disperznim sustavima, posebno onima u kojima su čestice disperzne faze koloidne veličine. Detaljno je opisana primjena ultrazvuka u te svrhe kao i temelji akustične spektroskopije. Tom suvremenom metodom određena je veličina i raspodjela veličine čestica tri različita uzorka titanijevog dioksida, TiO2. Jedan od tih uzoraka očito je namijenjen primjeni u proizvodnji sredstava za sunčanje dok je drugi primjenjiv u proizvodnji boja (čestice su veće). Treći uzorak je pokazao gotovo monodisperzne čestice nanometarske veličine (31 nm) i svakako je namijenjen za neke specijalne namjene. Izmjerena je i promjena zeta potencijala čestica s promjenom pH. Uočena je promjena karakteristična za okside metala: pozitivan zeta potencija pri niskim i negativan pri visokim vrijednostima pH.This work describes various techniques for particle size and particle charge determination in disperse systems, particularly in those where particles are colloidal in size. The application of ultrasound for these purpose is described in details as well as the fundamentals ofAcoustic Spectroscopy. By using this modern technique, particle sizes and distributions of three different titania samples were determined. One of them is clearly used in preparation of sunscreens while the other for applications in paints (particles are much larger and size distribution is wider). The third samples exhibited almost monodispersed nanosized particles (31 nm) and it is undoubtedly prepared for some special applications. The variation of zeta potential with change in pH was also determined. As usual for metal oxide particles, zeta potential is positive at low pH values and negative at higher (iep is at pH 2.5)
Determination of cationic surfactants in comercial disinfectant for wounds
No full textTenzidi ili površinski aktivne tvari su skupina molekula koje se najčešće nalaze u sastavu različitih kućanskih sredstava (detergenti, sredstva za pranje i čišćenje) iz svakodnevne uporabe. Njihova glavna odlika je smanjivanje površinske napetosti, a funkcija im je čišćenje ili dezinfekcija. Dijele se na kationske, anionske, amfolitske i neionske tenzide. Kationski tenzidi na hidrofilnom kraju molekule imaju pozitivno nabijeni ion, kation. Primjeri kationskih tenzida su kvaterni amonijevi spojevi, a najpoznatiji je cetilpiridnijev klorid, CPC. Za određivanje tenzida u komercijalnim proizvodima, najviše se koriste potenciometrijske titracije. Direktna potenciometrijska titracija korištena je za određivanje sadržaja kationskog tenzida oktenidin dihidroklorida i amfolitskog tenzida kokoamilopropil betaina (CAPB) u formulaciji komercijalnog proizvoda za dezinfekciju rana, Octenisept®. Pri sniženom pH (4,9) CAPB se ponaša kao kationski tenzid, što omogućuje mjerenje ukupnog udjela tenzida kationskog karaktera u uzorku. Za određivanje je korištena i metoda standardnog dodatka. Na temelju izvedenog eksperimenta i dobivenih rezultata utvrđena je točna koncentracija kationskog tenzida, OCL - c(OCL)= 1,5474 x 10-3 mol/L. (0,096 %) i amfolitskog tenzida, CAPB - c(CAPB)= 1,6387 x 10-3 mol/L (0,056 %); a koji se nalazi u uzorku Octenisept®.Tensides or surfactants are group of molecules commmonly found as components of various household cleaners (detergents, other cleaning products) from everyday use. Tensides are best known for their solubility and cleaning properties. They are generally classified as cationic, anionic, ampholytic and nonionic surfactants. Hydrophilic end of cationic surfactant contains a positively-charged ion, or cation. Most common type of cationic surfactants are the quaternary ammonium compounds, best one known is Cetylpyridinium chloride CPC. Potentiometric titrations are used for determination of surfactants in comercial products. Direct potentiometry is a method is used for determination of cationic surfactant Octenidine dihydrochloride and ampholytic surfactant Cocamidopropyl betaine which are components of comercial disinfectant for wounds, Octenisept®. Total share of surfactant with cationic character was measure at reduced pH (4,9) value because that is where CAPB is acting like a cationic surfactant. Based on performed experiment and given results, it was detemined exact concetration of cationic surfactant, OCL - c(OCL)= 1,5474 x 10-3 mol/L. (0,096 %) and ampholytic surfactant, CAPB - c(CAPB)= 1,6387 x 10-3 mol/L (0,056 %); which are found in sample of Octenisept®
Environmental pollution
No full textProblem oneĉišćenja prirode i okoliša trajna je pojava tijekom povijesti našeg planeta, ali je izrazito pojaĉan posljednjih nekoliko desetljeća. Oneĉišćenje prirode i okoliša svako je unošenje štetnih tvari i energije koje narušava prirodni sklad vode, zraka i tla. Oneĉišćenje vode predstavlja kvantitativno i kvalitativno odstupanje od normalnog i prirodnog, kemijskog, biološkog i fiziĉkog sastava i kakvoće. Glavni oneĉišćivaći su otpadne vode, koje ovisno o mjestu nastanka mogu biti komunalne, kućanske, oborinske, industrijske, procesne, itd. Oneĉišćenje zraka moţe biti lokalno i globalno. Lokalno oneĉišćenje je vezano uz gradove i industrijska podruĉja dok je globalno vezano za oneĉišćenje zraka u cijelosti. Glavni oneĉišćivaći zraka su razni plinovi koji nastaju kemijskim procesima te erupcije vulkana. Oneĉišćenje tla takoĊer moţe biti lokalno i globalno, lokalno je vezano uz velike gradove i veća industrijska podruĉja, a globalno je vezano uz prijenos štetnih tvari oborinama, vodotocima i podzemnim vodama. Glavni oneĉišćivaĉi tla su poljoprivredna proizvodnja i smeće.The environment and nature pollution problem is a permanent phenomenom throught the history of our planet and it is markedly enhanced in the last few decades. Every kind of harmful substances and energy that disrupts the natural balance of water, air and soil pollutes nature and the environment. Water pollution presents quantitative and qualitative deviation from the normal and natural, chemical, biological and pshysical composition and quality. The main polluters are waste waters, which depending on their origin can be communal, household, industrial and processed, stormwater, etc. Air pollution can be local and global. Local pollution is related to cities and industrial areas, while global pollution is related to air pollution altogether. The main air polluters are various gasses formed by chemical processes and volcanic eruptions. Soil pollution can also be local and global, local is related to big cities and major industrial areas, while global is related to the transmission of harmful substances such as: precipitation, streams and groundwaters. The main polluters are agricultural production and garbage
Concentration Compounds with Hidrxyquinolin Acid
No full textHidroksikinolinska kiselina naziv je za 4-hidroksikinolin-2-karboksilnu kiselinu koja nastaje kao metabolit triptofana u organizmu. Mnogi enzimi u svojim aktivnim mjestima sadrže metalne ione, pa se tako i hidroksikinolinska kiselina može kompleksirati s različitim kationima prijelaznih metala. U ovom završnom radu istražene su reakcije hidroksikinolinske kiseline s kationima cinka, kobalta, nikla, bakra, žive i srebra tako što su pripravljene serije otopina hidroksikinolinske kiseline i soli prijelaznih metala u vodi pri odreĎenom pH. Dobiveni su spojevi okarakterizirani infracrvenom spektroskopijom i termogravimetrijskom analizom. Predložene su strukture spojeva na temelju dobivenih rezultata.Hydroxyquinolinic acid is a common term used for 4-hydroxyquinolin-2-carboxylic acid which is a product of normal metabolism of triptophan. Large number of enzymes contain metal ion in their active site, so does hydroxyquinolinic acid which can coordinate with different cations of transition metals. In this thesis reactions of hydroxyquinolinic acid with cations of zinc, cobalt, nickel, copper, mercury and silver have been studied. Series of water solutions of hydroxyquinolinic acid and salts of transition metals were prepared within certain pH value. Synthesized compounds were characterized by infrared spectroscopy and thermogravimetric analysis. As a result, structures of synthesized compounds were proposed
Nuklearne reakcije
No full textNuklearne reakcije su detaljno istraživane od svog otkrića, kojemu je prethodilo otkriće radioaktivnosti. Dvije su vrste nuklearnih reakcija: fisija i fuzija i uključuju transmutaciju jezgre jednog elementa u jezgre dugih elemenata. U ovom radu opisano je korištenje fisije i fuzije s naglaskom na energetsko iskorištavanje. Fisija je trenutno glavni izvor energije, no fuzija se intenzivno istražuje jer je isplativija.Nuclear reactions have been widely explored since their discovery, which preceded the discovery of radioactivity. There are two types of nuclear reaction: fission and fusion, they are consisted of trasmutation of element core. In this work it is described usage of fission and fusion focusing on use in industry of energy. Fission is main source of energy so far, while fusion is yet exploring because it is more effective
Natural polymers
No full textMonomeri su male podjedinice, čijim kemijskim sastavljanjem nastaju makromolekule koje se zovu polimeri. Te vrlo velike molekule imaju značajnu ulogu u kemiji životnih procesa. Njihova fizička svojstva ovise o prirodi njihovih monomernih jedinica, jednako tako intramolekulska i intermolekulska međudjelovanja makromolekule, tj. polimera govore o njihovim sastavnim jedinicama. Prema podrijetlu dijele se na prirodne i sintetske polimere. Prirodni polimeri nazivaju se još i biopolimerima, te se za takve materijale kaže da potječu iz obnovljivih izvora.Monomers are small sub unitsthat chemically linked together from larger moleculs known as polymers. These very large moleculs have a significant role in the chemistry of life processes. Their physical properties depend on nature of their monomer units as equally as inter molecular interactions of polymers say abouth their basic components. Based on origin they are known as natural and synthetis polymes. Natural polymers are also known as bio polymers and it's said that they are originating from renewable sources
Determination of anionic surfactants in commercial systems with the new potentiometric sensor
No full textTenzidi su površinski aktivne tvari koje smanjuju površinsku napetost, a struktura im se sastoji od hidrofilne i hidrofobne skupine. Podijeljeni su na anionske, kationske, neionske i amfolitske. Anionski tenzidi su najšire primijenjeni i najčešće se koriste u obliku praškastih deterdženata jer lako uklanjaju mrlje s odjeće. Za određivanje koncentracije tenzida najčešće se koriste potenciometrijske titracije koje koriste ionsko-selektivne elektrode. Određivanje anionskih tenzida u realnom sustavu provedeno je koristeći novi potenciometrijski senzor koji se bazira na ionskom paru dimetildioktadecilamonijevtetrafenilboratu (DDA-TPB) kao elektroaktivnoj komponenti i o-nitrofeniloktileteru (oNPOE) kao plastifikatoru. Kao titrans je korištena standardna otopina cetilpiridinijeva klorida (CPC) koncentracije c = 4·10-3 mol/dm3, a analit je bila vodena otopina praškastog deterdženta Bioflower masene koncentracije γ = 5 g/dm3 koji, prema deklaraciji, sadrži 5-15% anionskih tenzida, dok se natrijev dodecilsulfat (NaDDS) koncentracije c = 4·10-3 mol/dm3 koristio kao standardni dodatak.Surfactants are surface active agents that lower the surface tension and contain hydrophilic and hydrophobic groups. They are divided into anionic, cationic, nonionic and ampholitic surfactants. Anionic surfactants are most widely used, specially in the form of powdered detergents due to their ability to remove stains from clothing. Determination of surfactants concentration is usually carried out by potentiometric titration using ion-selective electrode. Determination of anionic surfactants in real system was carried out using the newly synthesized potentiometric sensor based on an dimethyldioctadecylammonium tetraphenylborate (DDA-TPB) ion pair as the sensing element and o-nitrophenyl octyl ether (o-NPOE) as plasticizer. Standard solution of cetylpyridinium chloride (CPC) at concentration of c = 4·10-3 mol/dm3 was used as titrant, water solution of powdered detergent Bioflower at mass concentration of γ = 5 g/dm3 containing 5-15% surfactants, according to the declaration, was used as analyte and sodium dodecylsulfate (NaDDS) at concentration of c = 4·10-3 mol/dm3 was used as standard addition
Toxicity of silver nanoparticles
No full textToksičnost srebrnih nanočestica (AgNP) se istražuje na mnogim područjima. Najviše se istražuju njihova antibakterijska svojstva. Također se istražuje i njihov utjecaj na viruse i gljivice, a posebno toksičnost pri određenim koncentracijama. Pokazalo se kako čestice koje su veće, djeluju jače toksično od manjih. Također se pokazalo da će suspenzije u kojima se nalazi veća količina čestica srebra, odnosno iona, biti toksičnije od onih koje sadrže manju količinu čestica. Istraživao se utjecaj citotoksičnosti i genotoksičnosti AgNP, te se pokazalo kako veće koncentracije iona srebra djeluju toksičnije. Općenito, AgNP su veoma reaktivne, te zbog toga u većim količinama djeluju toksično. Pojedina istraživanja se slažu oko toksičnog utjecaja srebrnih nanočestica, dok određena istraživanja pobijaju te činjenice.The toxicity of silver nanoparticles (AgNPs) has been explored in many areas, most of which include their antibacterial properties. The influence on viruses and fungi has also been explored, especially the toxicity in certain concentrations. It's been proved that bigger particles are more toxic than smaller ones. Suspensions which contain greater amount of AgNPs or ions will be more toxic than those which contain smaller amount of those particles. The influence of cytotoxicity and genotoxicity of AgNPs has been explored and it has shown that greater concentrations of silver ions are more toxic. In general, AgNPs are very reactive and because of that, they are more toxic in greater amounts. Some researches agree about toxic effect of silver nanoparticles, while other disapprove those facts
Fran Bubanović-Founder of Chemistry in School of Medicine at University of Zagreb
No full textU radu su prikazani život i djelo prof. dr. Frana Bubanovića - od podrijetla i školovanja do znanstvenog doprinosa i umirovljenja. Za Frana Bubanovića možemo reći da je bio veliki vizionar kemije na tlu Hrvatske, njegov doprinos kemiji i općenito znanosti biti će trajno zapamćeni. Cilj mog diplomskog rada bio je prikazati Bubanovića kao svestranu osobu, istražiti njegov znanstveni doprinos kemiji, te prikazati njegovo područje interesa kroz tumačenje problematike njegovih znanstvenih i stručnih radova. Za Bubanovića s razlogom možemo reći da je veliki popularizator kemije. Njegova poruka je bila jasna - želio je kemiju prikazati u jednom novom svjetlu, kao zanimljivu granu na kojoj počiva sve i na kojoj se gradi sve što nas okružuje. Svoje znanje je nesebično dijelio sa svima koji su htjeli znati više. Bubanović se najviše zanimao za medicinsku kemiju i biokemiju pa ne čudi što su gotovo svi njegovi znanstveni radovi napisani iz tog područja. Njegova ostavština je golema, napisao je 23 znanstvena rada, nekoliko popularizacijskih knjiga, nekoliko sveučilišnih i srednjoškolskih udžbenika i preko 200 različitih stručnih članaka. Ovaj diplomski rad također sadrži i metodički dio kojemu je cilj da učenike na zanimljiv način, u vidu mini projekta provede kroz tematiku koju je proučavao profesor Bubanović. Naziv mini projekta je "Ključni gradivni kemijski elementi svakog organizma" i cilj mu je na zanimljiv način, kroz puno pokusa, obraditi sve one gradivne kemijske elemente koji sadrži svaki organizam.The paper presents the life and work of Professor Dr. Fran Bubanović - from his ancestry and education through scientific contributions and retirement. For Fran Bubanović we can say that he was a great visionary of chemistry on Croatian soil, so his contribution to chemistry and general science will be forever remembered. The aim of my graduation thesis was to show Bubanović as a versatile person, explore his scientific contributions to chemistry and to show his nature of occupations through the analysis of his scientific papers. With reason we can say that Fran Bubanović is great popularizer of chemistry. His message was clear - he wanted to show the chemistry in a new light, as an interesting branch on which all that is around us is based on. He shared his knowledge with everyone who wanted to know more. Bubanović cared most for Medical Chemistry and Biochemistry, so it is not surprising that almost all of his scientific papers belon to this area. His legacy is immense, he wrote 23 scientific papers, several promotional books, several university and high school textbooks and over 200 different professional articles. My graduation thesis also contains a teaching part aimed at learners in an interesting way of a mini project that follows the work of professor Bubanović. Title of the mini project is "The key chemical building blocks of every organism" and its aim is to on an interesting way, by means of number laboratory experiments, learners handle all those chemical building blocks containing each organism