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Microbial degradation of xenobiotics under aerobic conditions
No full textMnoga znanstvena otkrića omogućila su bolju kvalitetu života i dovela do povećane proizvodnje ksenobiotika koji se najčešće nepravilno odlažu te su jedan od glavnih uzročnika loše kakvoće okoliša. Značajna skupina takvih tvari antropogenog podrijetla su farmaceutici. Kako oni imaju složenu strukturu i mehanizam djelovanja na različite vrste organizama, važno je pronaći nove i učinkovite načine uklanjanja ksenobiotika te pratiti njihov utjecaj na okoliš. U tu svrhu se sve više koriste ekonomični i okolišno prihvatljivi procesi poput biorazgradnje, koji koristi enzimske i metaboličke sposobnosti mikroorganizama za razgradnju organskih onečišćujućih tvari. U ovome radu proveden je proces biorazgradnje β-laktamskog antibiotika amoksicilina pomoću okolišne Gram-pozitivne bakterije Bacillus subtilis. Biorazgradnja amoksicilina provedena je u šaržnim i aerobnim uvjetima. Početne koncentracije amoksicilina iznosile su 278 mg L^-1 (Bs-1) i 658 mg L^-1 (Bs-2). Na temelju rezultata testova osjetljivosti, aktivnost bakterijske kulture Bacillus subtilis nije inhibirana djelovanjem navedenog antibiotika. Učinkovitost procesa biorazgradnje amoksicilina iznosila je 99,7 %.Many scientific discoveries have enabled a better quality of life and led to increased production of xenobiotics, most of which are improperly disposed of and are a major cause of poor environmental quality. An important group of such substances of anthropogenic origin are pharmaceuticals. Since they have a complex structure and mechanism of action on different types of organisms, it is important to find new and effective methods for disposing of xenobiotics and monitoring their impact on the environment. To this end, economical and environmentally sound methods such as biodegradation, which utilises the enzymatic and metabolic capabilities of microorganisms to degrade organic pollutants, are increasingly being used. In this work, the process of biodegradation of the β-lactam antibiotic amoxicillin was carried out using the environmentally occurring Gram-positive bacterium Bacillus subtilis. The biodegradation of amoxicillin was carried out in a batch process and under aerobic conditions. The initial concentrations of amoxicillin were 278 mg L^-1 (Bs-1) and 658 mg L^-1 (Bs-2). According to the results of the susceptibility tests, the activity of the Bacillus subtilis bacterial culture was not affected by the mentioned antibiotic. The efficiency of the biodegradation process of amoxicillin was 99.7 %
Influence of process parameters on removal of acetamiprid with NF and RO membranes
No full textPesticidi i antiparazitici su toksični organski spojevi koji su zbog široke i rastuće primjene česta onečišćivala voda te kao takvi predstavljaju globalan ekološki i javnozdravstveni problem. Dodatni problem je činjenica da se ne mogu ukloniti konvencionalnim široko dostupnim procesima pročišćavanja voda. Tlačni membranski procesi su se pokazali učinkovitim, održivim procesima za separaciju ovakvih organskih spojeva iz voda, a postoji i potencijal za široku primjenu daljnjom optimizacijom procesa. U ovom radu se provelo ispitivanje utjecaja procesnih parametara (tlaka: 5, 10 i 15 bar i brzine strujanja: 2, 3 i 4 L/min) na učinkovitost separacije acetamiprida iz vodene otopine nanofiltracijom (NF) i reverznom osmozom (RO) u svrhu određivanja optimalnih uvjeta. Primjenom optimalnih uvjeta ispitana je učinkovitost separacije odabranih pesticida (tiakloprid i klotianidin) kao i antiparazitika (albendazol, febantel i mebendazol). Također je pri optimalnim uvjetima određena učinkovitost separacije smjese pesticida i antiparazitika. Učinkovitost separacije je analizirana tekućinskom kromatografijom visoke učinkovitosti. Separacija acetamiprida s NF provedena pri niskom radnom tlaku 5 bar pokazuje najlošije rezultate uspješnosti separacije u iznosu od 55 % do 65 %, dok pri višim tlakovima i brzinama strujanja pokazuje uspješnost separacije veću od 70 %. Separacija acetamiprida RO pokazuje uspješnost separacije veću od 90 % pri svim ispitivanim procesnim parametrima. Određeni su optimalni uvjeti za 1 mg/L otopinu acetamiprida računalnim programom Design Expert 7 i oni iznose: tlak 10 bar i brzina strujanja 4 L/min za NF, tlak 12,5 bar i brzina strujanja 4 L/min za RO proces. Febantel se u potpunosti separira i NF i RO membranom. NF procesom za ostale komponente osim febantela je utvrđena manja uspješnost separacije pri optimalnim uvjetima nego kod acetamiprida. Sve ostale komponente pokazuju uspješnost separacije 95 %) osim za albendazol kod kojeg je iznosila 85,2 %. Obje membrane pokazuju višu učinkovitost separacije komponenti u smjesi nego u binarnim otopinama.Pesticides and antiparasitics are toxic organic compounds which, due to their widespread and increasing use, often pollute water bodies and thus represent a global ecological and health problem. Another problem is the fact that they cannot be removed using conventional, widely used water treatment processes. Pressure-driven membrane processes have proven to be effective and sustainable methods for separating such organic compounds from water, and there is potential for their wider application through further process optimization. In this study, the influence of process parameters (pressure: 5, 10, and 15 bar; flow rate: 2, 3, and 4 L/min) on the removal efficiency of acetamiprid from aqueous solution by nanofiltration (NF) and reverse osmosis (RO) was determined together with optimal conditions. Using optimal conditions, the removal efficiency of selected pesticides (thiacloprid and clothianidin) and antiparasitics (albendazole, febantel, and mebendazole) was investigated. In addition, the efficiency of separation of mixtures of pesticides and antiparasitics was determined under optimal conditions. The removal efficiency was analysed by high-performance liquid chromatography. The separation of acetamiprid by NF at a low operating pressure of 5 bar showed the lowest separation efficiency, ranging from 55% to 65%, while the efficiency at higher pressures and flow rates was above 70%. The removal of acetamiprid by RO showed an efficiency of over 90% for all tested process parameters. The optimal conditions for a 1 mg/L acetamiprid solution were determined using Design Expert 7 software: 10 bar pressure and 4 L/min flow rate for the NF, and 12.5 bar pressure and 4 L/min flow rate for the RO process. Febantel was completely separated from both the NF and RO membranes. For other components (except febantel), the NF process showed lower removal efficiency compared to acetamiprid under optimal conditions. All other components showed removal efficiencies below 55%, indicating that component characteristics need to be considered when optimizing organic pollutant removal. The RO membranes also showed an exceptionally high removal efficiency of over 95% for the other components tested, with the exception of albendazole, for which it was 85.2%. Both membranes showed a higher removal efficiency for components in mixtures than in binary solutions
Purification of the MenD enzyme for application in biocatalysis
No full textU dobu zelene revolucije svijest o potrebi pronalaženja održivijih alternativa tradicionalnim industrijskim procesima, vrstama kemikalija i materijalima svakog je dana sve veća. Gotovo svi industrijski procesi koriste katalizatore koji su uglavnom štetni za okoliš, nerazgradivi i zahtijevaju vrlo oštre reakcijske uvjete. S druge strane, biokatalizatori su najčešće enzimi, molekule evoluirale u fiziološkom okruženju koje su u potpunosti biorazgradive, a opstaju u blagim reakcijskim uvjetima gdje pokazuju najveću aktivnost i učinkovitost. Sama biokataliza pronalazi svoje mjesto u gotovo svim načelima zelene kemije, a potencijal koji biokatalizatori pokazuju za zamjenu tradicionalnih kemijskih procesa, čineći ih ekološki prihvatljivijima eksponencijalno raste razvojem inovacija i tehnoloških napredaka posebno na područjima enzimsko-proteinskog i genetičkog inženjerstva. Enzim MenD, 2-sukcinil-5-enolpiruvil-6-hidroksi-3-cikloheksen-1-karboksilat (SEPHCHC)-sintaza ključan je u sintezi menakinona, ima potencijalno antibiotsko djelovanje u lijekovima protiv tuberkuloze, katalizira reakcije nastanka spojeva s 1,4-funkcionalnim skupinama i jedini je enzim za kojeg je poznato da katalizira reakciju adicije ThDP-a na β-ugljik sekundarnog supstrata. U ovom radu provedeno je pročišćavanje uzoraka proteina MenD, masene koncentracije =41,67 mg/mL. Uzorak je pročišćen afinitetnom kromatografijom na uređaju ÄKTAprime plus, koristeći HisTrap™ excel kromatografsku kolonu. Ovakve kromatografske kolone omogućavaju hvatanje i pročišćavanje proteina označenih histidinom afinitetnom kromatografijom na imobiliziranim ionima metala. Uspješnost pročišćavanja provjerena je elektroforezom, kojom je ispitana prisutnost MenD-a u pročišćenim frakcijama.In the era of green revolution, awareness of the need to find sustainable alternatives to traditional industrial processes, chemicals and materials grows greater every day. Nearly every industrial process uses catalysts that are harmful to the environment, nondegradable and require very harsh reaction conditions. On the other hand, biocatalysts are mostly enzymes, molecules evolved in a physiological environment that are fully biodegradable and survive in mild reaction conditions where they show the greatest activity and efficiency. Biocatalysis follows almost every green chemistry principle and the potential that biocatalysts have regarding replacing traditional chemical processes, making them more environmentally friendly, grows exponentially with the development of innovations and technological advancements especially in areas of enzymatic and genetic engineering. MenD is the designation for the enzyme 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase, which is important in the synthesis of menaquinone, has potential antibiotic properties in anti-tuberculosis medicines, catalyses reactions that give
1,4-functionalized products and is the only known enzyme that catalyses the addition of ThDP on β-carbon of a secondary substrate. Purification of protein sample containing MenD, mass concentration of γ=41,67 mg/mL, was performed in this work. The sample was purified by affinity chromatography on ÄKTAprime plus via HisTrap™ excel chromatography column. These chromatography columns enable the capture and purification of histidine labelled proteins by immobilized metal affinity chromatography. The success of the purification was determined using electrophoresis, which tested the presence of MenD in purified fractions
Solution-based synthesis of high-entropy oxide of transition metals
No full textCilj ovog rada bila je sinteza visoko-entropijskog oksida kemijske formule (TiZrHfNbTa)O11. Korištena su četiri postupka sinteze: limunski, koprecipitacijski, sol-gel i hidrotermalni. Kao polazni reaktanti za sve četiri sinteze korišteni su kloridi niobija (NbCl5), tantala (TaCl5), hafnija (HfCl4) i cirkonija (ZrCl4) te titanijev butoksid (Ti(C4H9O)). Svi sintetizirani uzorci karakterizirani su infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR) te pretražnom elektronskom mikroskopijom i energijski razlučujućom rendgenskom spektroskopijom (SEM/EDXS). Na temelju SEM/EDXS rezultata zaključeno je da su kod svih sintetiziranih uzoraka udjeli niobija, tantala, hafnija i cirkonija približno jednaki dok je titanija gotovo dvostruko više, što je vjerojatno posljedica njegove veće reaktivnosti budući da se u reakcijsku smjesu uvodi u obliku alkoksida. Uzorci visoko-entropijskih oksida koji su u
SEM/EDXS analizama pokazali najveći stupanj homogenosti i dobro poklapanje množinskih udjela pojedinih elemenata s teorijskim udjelima, dodatno su analizirani rendgenskom difrakcijskom analizom (XRD). Na temelju XRD analize zaključeno je da se dobiveni difraktogrami žarenih visoko-entropijskih oksida podudaraju s literaturnim podacima čime je potvrđeno da su svi primijenjeni postupci prikladni za sintezu HEO ciljanog sastava. Iz difraktograma prekursora dobivenog hidrotermalnim postupkom zaključeno da tim postupkom sinteze nije moguće direktno dobiti oksid bez dodatnog koraka žarenja.The aim of this work was the synthesis of high-entropy oxide with the chemical formula (TiZrHfNbTa)O11. Four synthesis methods were used: citric, coprecipitation, sol-gel, and hydrothermal. Chlorides of niobium (NbCl5), tantalum (TaCl5), hafnium (HfCl4), and zirconium (ZrCl4), as well as titanium butoxide (Ti(C4H9O)), were used as starting reactants for all four syntheses. All synthesized samples were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDXS). Based on SEM/EDXS results, it was concluded that the contents of niobium, tantalum, hafnium, and zirconium in all synthesized samples are approximately equal, while the content of titanium is almost twice as high, likely due to its higher reactivity since it is introduced into the reaction mixture in the form of an alkoxide. High-entropy oxide samples that showed the highest degree of homogeneity in SEM/EDXS analyses and good matching of elemental molar ratios with theoretical values were further analyzed using X-ray diffraction analysis (XRD). Based on XRD analysis, it was concluded that the diffractograms of annealed high-entropy oxides match the literature data, confirming that all applied methods are suitable for the synthesis of HEO with the targeted composition. From the diffractogram of the precursor obtained by the hydrothermal method, it was concluded that this synthesis method does not directly yield an oxide without an additional annealing step
Spectrophotometric determination of ionisation constant of resveratrol analogues
No full textPoznavanje konstante ionizacije (Ka) izuzetno je važno prilikom razvoja novih lijekova s obzirom da nam omogućuje predviđanje ponašanja lijekova u fiziološkim uvjetima. Također, ima važnu ulogu kod određivanja ADMET (apsorpcija, distribucija, metabolizam, izlučivanje, toksičnost) svojstava lijekova. Vrijednosti pKa moguće je odrediti različitim metodama poput potenciometrije, kapilarne elektroforeze, tekućinske kromatografije te UV/VIS spektrofotometrije. U ovom radu određene su pKa vrijednosti novih analoga rezveratrola
UV/VIS spektrofotometrijskom metodom. Eksperimentalno određene pKa vrijednosti iznose: 9.80±0.09, 9.94±0.14, 9.10±0.05, 9.44±0.04 i 9.58±0.16.The knowledge of ionisation constant (Ka) is extremly important for the development of new drugs as it allows us to predict the behavior of drugs under psysiological conditions. It also plays a crucial role in determinig the ADMET (absorption, distribution, metabolism, excretion, toxicity) prosperties of drugs. The pKa values can be determined using various methods such as potentiometry, capillary electrophoresis, liquid chromatography, and UV/VIS spectrophotometry. In this study, the pKa values of new resveratrol analogs were determined using the UV/VIS spectrophotometric method. The experimentally determined pKavalues are: 9.80±0.09, 9.94±0.14, 9.10±0.05, 9.44±0.04 and 9.58±0.16
Screening of N-acetylneuraminic acid synthase analogues on unnatural substrates
No full textSijalinske kiseline mogu posredovati ili modulirati u širokom spektru fizioloških i patoloških procesa zbog svoje sveprisutne distribucije i strateške lokacije. U posljednjem desetljeću postignut je značajan napredak u proučavanju glikana na ljudskim stanicama, kao i njihove uloge u interakcijama među stanicama. Ugljikohidrati igraju mnogobrojne uloge u različitim organizmima, uključujući razvoj, signalizaciju, interakcije između domaćina i parazita te imunološku funkciju. Iako je provedeno mnogo istraživanja, biologija sijalinske kiseline je još uvijek rastuće područje velikog potencijala čije su primjene tek započele. U ovom radu provedena je kondenzacijska reakcija šećera (L-arabinoza, D-galaktoza, D-liksoza,
D-(+)-manoza) i fosfoenolpiruvata uz prisutnost metalnog kofaktora Co2+. Reakcije su katalizirane analozima sintaze N-acetinneuraminske kiseline (PNH2, PNH5), umjetno dobiveni na temelju sličnosti sa sintazom neuraminske kiseline iz bakterije Neisseria meningitidis. Produkt reakcija su različite sijalinske kiseline. Provedena su ispitivanja s ekstraktom stanica te s pročišćenim enzimom radi potvrde aktivnosti enzima i nastajanja analognih produkata sijalinske kiseline. Uočena je najveća kompatibilnost enzima PNH5 s testiranim šećerima.Sialic acids can mediate or modulate a wide range of physiological and pathological processes due to their omnipresent distribution and strategic location. In the past decade, significant progress has been made in the study of glycans on human cells, as well as their role in cell-cell interactions. Carbohydrates play numerous roles in various organisms, including development, signaling, host-parasite interactions, and immune function. Although much research has been conducted, sialic acid biology is still an emerging field with great potential, while its applications are just beginning. In this study, a condensation reaction of sugars (L-arabinose, D-galactose, D-lyxose, D-(+)-mannose) and phosphoenolpyruvate in the presence of the metal cofactor Co2+. The reactions were catalyzed by analogs of
N-acetylneuraminic acid synthase (PNH2, PNH5), which were artificially derived based on their similarity to the neuraminic acid synthase from the bacterium Neisseria meningitidis.
The product of the reactions are different sialic acids. Assays were conducted on both
cell-free extracts and purified enzyme to confirm the enzyme activity and the formation of sialic acid analogs. The highest compatibility of the enzyme PNH5 with the tested sugars was observed
Multilayered polymer nano-coatings of fatty acids on copper cross-linked by ionizing radiation
No full textSvakodnevni tehnološki napredak omogućava razvoj novih metoda sinteze i karakterizacije materijala, što potiče znanstvenike da istražuju i razvijaju nove i funkcionalnije prevlake koje mogu zadovoljiti specifične potrebe različitih industrija te pri tome biti ekološki prihvatljivi.
U ovom radu ispitana su zaštitna svojstva prevlaka nastalih samoorganizacijom molekula (SAM-ovi) četiri masne kiseline na površini bakra koje su potom umrežene ionizirajućim gama zračenjem. Prevlake neumreženih SAM-ova u korozijskim uvjetima nisu dugotrajno postojane te se relativno brzo uklone s površine. Primjenom gama zračenja inicira se polimerizacija masnih kiselina čime se postiže stabilnija, homogenija i dugotrajnija prevlaka. U ovome radu ispitana su zaštitna svojstva jednostavnih i slojevitih umreženih samoorganiziranih slojeva četiriju masnih kiselina (Crot, C6, C18 i C22) nanošenih metodom uranjanja. Zaštitna svojstva nastalih ispitana su elektrokemijskim metodama (metoda Tafelove ekstrapolacije i elektrokemijska impedancijska spektroskopija-EIS) u otopini koja simulira atmosferske uvjete, a prevlake su dodatno karakterizirane metodom kontaktnog kuta i termogravimetrijskom analizom. Dobiveni rezultati elektrokemijskih ispitivanja su pokazali da od jednostavnih prevlaka C22 prevlake pružaju najbolja zaštitna svojstva, C18 nešto slabija, a C6 najslabija zaštitna svojstva dok prevlake od Crot kiseline stvaraju zaštitu sličnu C22 prevlaci. Ispitivanja na slojevitim prevlakama pokazala su nešto slabija zaštitna svojstva, te od svih ispitivanih prevlaka C22 prevlaka je pokazala najbolja zaštitna svojstva. Vrijednosti kontaktnih kutova određene goniometrijom kod jednoslojnih prevlaka ukazuju na hidrofobnost svih prevlaka osim C6 prevlake, dok su od slojevitih prevlaka jedino kombinacije C6-C18 također hidrofilne, a ostale dvije kombinacije imaju hidrofobna svojstva. Termogravimetrijska analiza pokazuje da se razgradnja jednostavnih prevlaka odvija u jednom stupnju te da maksimalna temperatura raste s porastom duljine lanca. Razgradnja u dva stupnja se javlja kod većine slojevitih prevlaka, uz prvi pad mase bliži temperaturi određenoj za kraću masnu kiselinu, što ukazuje na manju termičku stabilnost u odnosu na jednostavne prevlake C18 i C22.Everyday technological progress enables the development of new methods of material synthesis and characterization, which encourages scientists to research and develop new and more functional coatings that meet the specific needs of different industries while being environmentally friendly. In this work, we tested the protective properties of the coatings created by the self-assembly of molecules (SAMs) of four fatty acids on the surface of copper, which were then cross-linked by ionizing gamma radiation. The coatings of
non-cross-linked SAMs are not long-lasting under corrosive conditions and are removed relatively quickly from the surface. The applying gamma radiation initiates the polymerization of fatty acids, resulting in a more stable, homogeneous and long-lasting coating. In this work, the protective properties of simple and layered cross-linked SAMs of four fatty acids (Crot, C6, C18, and C22) were investigated. The protective properties were tested by electrochemical methods (Tafel extrapolation method and electrochemical impedance spectroscopy-EIS) in a solution simulating atmospheric conditions, and the coatings were additionally characterized by the contact angle method and thermogravimetric analysis.
The results of the electrochemical tests showed that of the simple coatings, the C22 coatings had the best, the C18 coatings the slightly weaker and the C6 coatings the weakest protective properties. The Crot coatings offered only slightly weaker protection compared to the C22 coatings. Tests with layered coatings showed slightly weaker protective properties, and of all the tested coatings the C22 coating showed the best protective properties.
The contact angle values determined by goniometry for single-layer coatings indicate the hydrophobicity of all coatings except the C6 coating, while of the layered coatings, only the C6-C18 combinations are also hydrophilic, and the other two combinations have hydrophobic properties. Thermogravimetric analysis shows that the decomposition of simple coatings takes place in one step and that the maximum temperature increases with the increase in chain length. Degradation in two stages occurs with most layered coatings, with the first drop in mass closer to the temperature determined for the shorter fatty acid, which indicates lower thermal stability compared to simple C18 and C22 coatings
Synthesis of new ferrocene-pyridine ligands and their metal complexes
No full textCilj ovog rada bila je sinteza novih ferocen-piridinskih liganada (6–9) i njihovih
Re(I)-(6-Re–8-Re) i Ru(II)-kompleksa (6-Ru-cim–9-Ru-cim, 8-Ru–fenil). Ligandi su sintetizirani regioselektivnom 1,3-dipolarnom cikloadicijom iz prethodno sintetiziranih terminalnih ferocenskih alkina (3–5) i kloriranog piridin-2-aldoksima (2). Terminalni ferocenski alkini (3–5) sintetizirani su O-propargiliranjem ferocen alkohola, ferocen aldoksima i ferocen karboksilne kiseline s propargil-bromidom uz prisutstvo baze. Klorirani aldoksimski
prekursor (2) sintetiziran je iz piridin-2-aldehida u dva stupnja. U prvom je stupnju
piridin-karbaldehid preveden u piridin-aldoksim (1), koji je u drugom stupnju kloriran s N-klorsukcinimidom. Sintetizirani piridin-izoksazoli (6–9) korišteni su kao ligandi za metalne komplekse s renij(I) pentakarbonil-kloridom (6-Re–8-Re), diklor(benzen)rutenij(II) dimerom (8-Ru–fenil) i diklor(p-cimen)rutenij(II) dimerom (6-Ru-cim–9-Ru-cim). Strukture spojeva potvrđene su spektroskopijom 1H i 13C NMR.The aim of this work was the synthesis of new ferrocene-pyridine ligands (6–9) and their Re(I)-(6-Re–8-Re) and Ru(II)-complexes (6-Ru-cym–9-Ru-cym, 8-Ru-phenyl). Ligands were synthesized by regioselective 1,3-dipolar cycloaddition from previously synthesized terminal ferrocene alkynes (3–5) and chlorinated pyridine-2-aldoxime (2). Terminal ferrocene alkynes (3–5) were synthesized by O-propargylation of ferrocene alcohol, ferrocene aldoxime and ferrocene carboxylic acid with propargyl bromide in the presence of a base. The chlorinated aldoxime precursor (2) was synthesized from pyridine-2-carbaldehyde in two steps. In the first step, pyridine carbaldehyde was converted into pyridine aldoxime (1), which was chlorinated with N-chlorosuccinimide in the second step. Synthesized pyridine isoxazoles (6–9) were used as ligands for metal complexes with rhenium(I) pentacarbonyl chloride, dichloro(benzene)ruthenium(II) dimer and dichloro(p-cymene)ruthenium(II) dimer.
The structures of the compounds were confirmed by 1H and 13C NMR spectroscopy
Novel 1,2,3-triazole derivatives of benzoxazole and benzimidazole: synthesis and structural characterization
No full textU ovom radu opisana je sinteza novih 1,2,3-triazolnih derivata benzoksazola i benzimidazola klik-reakcijom, njihova strukturna karakterizacija spektroskopijom NMR te analiza in silico. Reakcijom ciklokondenzacije odgovarajućih aminofenola pripravljeni su derivati benzo[d]oksazol-2-tiola 2 i 3 koji su reakcijom kondenzacije s 2-(klormetil)-1H-benzo[d]imidazolom 1 prevedeni u hibride benzimidazola i benzoksazola 4 i 5 premoštene tiometilenskom spojnicom. Reakcijom N-propargiliranja dobivenih hibrida pripravljeni su alkilirani derivati 7 i 8 koji su 1,3-dipolarnom cikloadicijom kataliziranom bakrom s prethodno pripravljenim azidima 9–16 prevedeni u ciljane 1,2,3-triazolne derivate benzimidazola i benzoksazola 18–31. Strukturna karakterizacija sintetiziranih spojeva provedena je spektroskopijom 1H- i 13C-NMR, dok su biološka djelovanja predviđena PASS analizom in silico.This paper describes the synthesis of novel 1,2,3-triazole derivatives of benzoxazole and benzimidazole by click reaction, their structural characterization using NMR spectroscopy and in silico analysis. Derivatives of benzo[d]oxazole-2-thiol 2 and 3 were prepared through cyclization of appropriate aminophenols, followed by condensation with 2-(chloromethyl)-1H-benzo[d]imidazole 1 to obtain hybrids of benzimidazole and benzoxazole 4 and 5 bridged by a thiomethylene linker. N-propargylation reaction of the resulting hybrids yielded alkylated derivatives 7 and 8, which underwent copper catalyzed 1,3-dipolar cycloaddition with prepared azides 9–16 to yield targeted 1,2,3-triazole derivatives of benzimidazole and benzoxazole 18–31. Structural characterization of novel compounds was carried out by 1H- and 13C-NMR spectroscopy, while biological activity was predicted by in silico PASS analysis
Preparation of activated sludge samples for chromatographic analysis of pollutants
No full textPraćenje onečišćivala u uzorcima najučinkovitije se postiže kromatografskim metodama. Međutim, da bi uzorak mogao biti analiziran spomenutom metodom potrebno ga je prethodno pripremiti i prevesti u oblik adekvatan za analizu. U ovom slučaju određivala su se onečišćivala u aktivnom mulju koji je nastao tijekom procesa biorazgradnje. Naime, proces biorazgradnje uobičajeno je sastavni dio postupka obrade otpadnih voda pri čemu nastaju velike količine aktivnog mulja. Biorazgradnja je proces tijekom kojeg različiti mikroorganizmi pretvaraju materijale u prirodne tvari koje potječu iz okoliša kao što su voda ili ugljikovi spojevi. Cilj ovog rada bio je razviti adekvatnu metodu pripreme uzoraka aktivnog mulja nastalog procesom biorazgradnje kako bi se odredila ostatna onečišćivala u spomenutom aktivnom mulju kromatografskom analizom. Onečišćivala praćena u ovom radu su ksenobiotici iz skupine antiparazitika (mebendazol, albendazol i febantel) i insekticida (klotianidin, acetamiprid i tiakloprid). Ksenobiotici pripadaju skupini mikroonečišćivala, odnosno spojevima koji se mogu naći u vodenim sustavima kao posljedica antropogenog utjecaja. Optimizirali su se uvjeti za ekstrakciju mućkanjem (vrijeme trajanja ekstrakcije, volumen otapala, broj okretaja i temperatura ekstrakcije) i ultrazvučnu ekstrakciju (način pripreme mulja, vrijeme trajanja ekstrakcije, volumen otapala, snaga ultrazvučne kupelji i temperatura ekstrakcije). Izabrano optimalno otapalo bila je smjesa otapala MeOH: ACN=50:50 (v:v) ukupnog volumena 5 mL.Monitoring of pollutants in samples is most effectively achieved by chromatographic methods. However, in order for the sample to be analyzed by the mentioned method, it should be prepared beforehand and translated into a form adequate for analysis. In this case, pollutants were determined in the activated sludge that was created during the biodegradation process. Namely, the biodegradation process is usually an integral part of the wastewater treatment process, where large amounts of activated sludge are produced. Biodegradation is the process during which various microorganisms convert materials into natural substances that originate from the environment such as water or carbon compounds. The goal of this work was to develop an adequate method of preparing samples of activated sludge produced by the biodegradation process in order to determine the remaining pollutants in the mentioned activated sludge by chromatographic analysis. The pollutants monitored in this work were xenobiotics from the group of antiparasitics (mebendazole, albendazole and febantel) and insecticides (clothianidin, acetamiprid and thiacloprid). Xenobiotics belong to micropollutants, compounds that can be found in water systems as a result of anthropogenic influence. The conditions for extraction by shaking (extraction time, solvent volume, number of revolutions and extraction temperature) and ultrasonic extraction (method of sludge preparation, extraction time, solvent volume, power of the ultrasonic bath and extraction temperature) were optimized. The optimal solvent chosen was the solvent mixture MeOH: ACN=50:50 (v:v), total volume 5 mL