Ispitivanje reakcija hidrolize i kompleksiranja u rastvorima aluminijum(III)-jona i nekih fluorohinolona metodom elektrosprej-tandem masene spektrometije

Predmet ove disertacije je proučavanje reakcija hidrolize aluminijum(III)-jona i reakcija kompleksiranja aluminijum(III)-jona i fluorohinolona (HQ) (fleroksacina, ciprofloksacina i moksifloksacina). U okviru disertacije određena je specijacija u rastvorima aluminijum(III)-jona i rastvorima aluminijum(III)-jona i fluorohinolona (HQ) sa ciljem boljeg razumevanja farmako i toksikokinetike fluorohinolonskih antibiotika u prisustvu lekova na bazi aluminijuma (antacidi, vakcine, dijalizatni rastvori). Proučavanja su vršena elektrosprej masenom spektrometrijom, (ESI MS), tandem masenom spektrometrijom (MS/MS) i masenom spektrometrijom, gde je jonizacija potpomognuta laserskom desorpcijom iz matriksa (MALDI MS). Proučavanjem navednih sistema, pomenutim eksperimentalnim tehnikama i kompjuterskom obradom podataka, korišćenjem programa Hyss 2006 i modela veštačkih neuronskih mreža (AAN) dobijeni su sledeći rezultati: Pri proučavanju hidrolize aluminijuma vrste identifikovane u rastvorima aluminijum(III)-jona, koncetracije 0,03 do 5,0 mmol/dm3, su vrste sa naelektrisanjem +1, +2 i +3, formirane u opsegu pH od 3-6. Monomerne i dimerne vrste su dominantne do pH 3,8. ESI MS spektri ukazuju na formiranje malih polimernih vrsta (Al3–Al5) na pH 4,8. Sa povećanjem pH i koncetracije aluminijum(III)-jona identifikuju se srednji polimeri (Al6–Al10). Daljim povećanjem pH i koncentracije aluminijum(III)-jona nastaju viši polimeri (Al11–Al13). Viši polimeri su privremene vrste koje postoje relativno kratko vreme nakon pripreme rastvora. Na pH oko 6,4 počinje formiranje taloga. Rezultati dobijeni ESI masenom spektrometrijom su u saglasnosti sa rezultatima dobijenim 27 Al NMR spektroskopijom i potenciometrijom.Th is dissertation comprises investigation of hydrolysis aluminum(III)-ion and aluminum(III)-ion and fl uoroquinolones (FQLs) family members (fl eroxacin, ciprofl oxacin and moxifl oxacin) complexation reactions. Within present study it is determined speciation in solutions of aluminum(III)-ion and in solutions of aluminum(III)-ions and fl uoroquinolones (FQLs) in aim to better understand pharmacotherapy and toxicokinetics of fl uoroquinolones antibiotics in the presence of aluminum-based drugs (antacids, vaccines, solutions for dialysis). So the solutions were investigated by electrospray mass spectrometry (ESI MS), tandem mass spectrometry (MS/MS) and mass spectrometry with matrix-assisted laser desorption ionization (MALDI MS). Investigation or these systems, using the above mentioned experimental techniques and computer processing data by using Hyss 2006 soft ware and artifi cial neural network (AAN) model gave the following results: Th e hydrolysis of aluminum(III)-ion have been investigated in the solutions of concentration level 0,03 to 5,0 mmol/dm3, in the pH range 3 to 6. Th e species with electric charge +1, +2 and +3, formed in this conditions. Monomeric and dimeric species were dominant until the pH value of 3,8. ESI MS spectra indicate the formation of small polymeric species (Al3-Al5) at pH 4,8 value. With the increase pH and concentrations values of aluminum(III)-ion, it was identifi ed intermediate polymers (Al6-Al10). With further increase in pH and the concentration of aluminum(III)-ion, higher polymers (Al11-Al13) were generated. Higher polymers are species that are relatively short period of time existing. At a pH of about 6,4 the sludge formed. Th e results obtained by ESI MS spectra are in good agreement with the results obtained by 27Al NMR spectroscopy and by potentiometry

Spectrophotometric study of solution equilibria between Al3+ ion and L-histidine

Aluminium(III) ion and L-histidine (HHis) react in water solution to yield two mononuclear binary complexes [Al(HHis)]3+ and [Al(HHis)His] 2+. The over-all stability constants for these complexes were calculated by non-linearleast-squarestreatment of the spectrophotometric data and found to be: log β1,1,1 = 13.12 ± 0.04, log β1,2,1 = 20.9 ± 0.1, respectively. Indices refer to stoichiometric coefficients in complexation equilibrium: p Al + q His + r H → [AlpHisqHr]. The possible structures of the complexes in solution, are discussed.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Uranium contents from bomb craters

Depleted uranium (DU) is a by-product of uranium enrichment process and its use is very dangerous and harmful. We measured uranium concentration in the surface soil (0-5 cm depth) from bomb craters caused by cruise missiles in which DU might have been used as counterweights during NATO attack. Total uranium concentration and isotopic ratio were determined using y-spectrometry and inductively coupled plasma method. Obtained results were in the range 1.7 - 22 mg/kg dry soil that was comparable to the uranium values found in off-side locations of Serbian soils

Spectrophotometric and 27-Al NMR characterization of aluminum(III) complexes with L-histidine

The complex formation between L-histidine (HHis) and aluminum(III) ion in water solutions was studied by UV spectrophotometric and 27-Al NMR measurements at 298 K. UV spectra were measured on solutions in which the total concentration of histidine was from 15.0 to 50.0 mmol/dm(3) and the concentration ratio of histidine to aluminum was varied from 3 : 1 to 10 : 1 in the pH range between 4.2 and 6.0. The spectra were taken in the wavelength interval 240 - 340 nm. Nonlinear least-squares treatment of the spectrophotometric data indicates the formation of the complexes Al(HHis)(3+), Al(His)(2+), Al(HHis)His(2+), and Al-2(OH)His(4+) with the overall formation constants beta(p,q,r): log beta(1,1,1) = 11.90 +/- 0.04, log beta(1,1,0) = 7.25 +/- 0.08, log beta(1,2,1) = 20.1 +/- 0.1, and log beta(2,1,1) = 5.92 +/- 0.12 ( p, q, r are stoichiometric indices for metal, ligand, and proton, respectively). Al-27-NMR spectra were taken on solutions with the concentration of aluminum 50 mmol/dm(3) and that of histidine 250 mmol/dm(3). In the pH interval 5.0 - 6.1, two resonances at 9.5 ppm and 12.0 ppm were assigned to Al(HHis)(2+) and Al( HHis)(His)(2+) (or Al(OH)(HHis)(2)(2+)), respectively

Occupational Exposure to Ionising Radiation At Copper Mill

The Copper Mill Sevojno produces various copper and copper alloy products for utilization in different industry sectors. Technological process of copper rolling from blocks to strips consists of cold and hot rolling. For the control of copper strip thickness radio-isotope strip thickness gauges are installed. These gauges are widely used for contactless measurement of the metallic or non-metallic strip thickness. At the Copper Mill Sevojno, radio-isotope strip thickness gauges are with radio-isotope Sr-90. The gauges are placed on the machines for cold rolling of copper and brass strips, named rolling mills. The employees that operate on these rolling mills are exposed to gamma radiation and are under legislation dosimetric control. The results of dosimetric monitoring of rolling mills workers are presented here. The doses, in terms of personal dose equivalent, Hp(10), are reported quarterly, as those workers are categorized as B group workers occupationally exposed to ionizing radiation. Measurements are done with thermoluminescent system that consists of Harshaw 6600 Plus automatic reader and thermoluminescent dosimeters for whole body TLD-100 (LiF:Mg,Ti). Annual doses are given for all four groups of monitored twenty-one persons for three-year period. The results show that maximal measured personal annual dose is less than recommended annual dose limit of 20 mSv.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Le Grand écho du Nord de la France

26 juin 19111911/06/26 (A93,N177).Appartient à l’ensemble documentaire : NordPdeC