Optimizacija i primena gasno-difuzione protočne injekcione metode za određivanje hlorida

A selective and sensitive procedure for the fast and indirect determination of chloride by the gas-diffusion FIA method has been optimized and applied for the determination of chloride in water samples which contained different amounts of the analyte. The examined samples were: seawater, tap water and very pure water from the water-steam system of the power plant "Nikola Tesla B" in Obrenovac. Application of an amperometric detector (model LC-17A; BAS, West Lafayette, USA) enables the detection limit to be decreased down to 0.05 mu mol/dm(3) of chloride, which col responds to 35.5 pg, and adjustment of the acceptor flow rate and direction inside the gas-diffusion unit. In this way the optimized FIA system has excellent repeatability. For 5 mu mol/dm(3) it was found to be 1.11% (n = 5). The throughput of this method is 60 samples per hour.Selektivan i osetljiv postupak za brzo, indirektno određivanje hlorida gasno-difuzionom metodom otpimizovan je i primenjen za određivanje hlorida u uzorcima voda sa vrlo različitim sadržajem ove vrste: morskoj, vodi za piće i vrlo čistim vodama u sistemu voda-para TE "Nikola Tesna B" u Obrenovcu. Upotreba amperometrijskog detektora tipa LC-17A omogućava snižavanje granice detekcije na 0.05 μmol/dm3 hlorida (što za uzorak zapremine 0.2 cm3 iznosi 35.5 pg) i podešavanje brzine i smera toka u gasno-difuzionoj jedinici. Ovako optimizovan protočni sistem ima odličnu reproduktivnost. Za hloridni standard koncentracije 5 μmol/dm3 relativna standardna devijacija iznosi 1.11 % (n = 5)

One-step purification and freeze stability of papain at acidic pH values

Papain is a proteolytic enzyme of great commercial value. It is a cysteine protease highly expressed in Carica papaya fruit latex, but also present in papaya leaves. Purification procedures mostly deal with the latex and include a combination of precipitation and/or chromatographic techniques. Due to its solubility, structure and activity characteristics, the pH and salt content play significant roles in handling papain extracts. Here we report a simple, rapid and easily scalable procedure for papain purification from papaya leaves, which contain different contaminants as compared to papaya latex. Sodium chloride precipitation of contaminants at pH 5 followed by ammonium sulphate precipitation resulted in the removal of other leaf proteins and protein fragments from papain solution and about a 3-fold purification. The procedure also benefits from the suppression of autoproteolysis and preservation of the native structure, as confirmed by FTIR analysis, and the high recovery of activity of over 80%

Effect of thermal stress of short duration on the red blood cell parameters of Barbus balcanicus Kotlik, Tsigenopulos, Rab, Berrebi, 2002

In this study, red blood cell parameters of Barbus balcanicus Kotlik, Tsigenopulos, Rab, Berrebi, 2002 subjected to acute thermal stress were investigated. Fish were caught by electro fishing in the Suturlija river, a small tributary of the river Vrbas (N latitude 44˚44' 38˝, E longitude 17˚ 09' 10˝) in summer (July) and transported to the laboratory. Fish were randomly distributed in four aquaria of 30 L each. In all the four aquaria, the water temperature was continuously kept at 19°C by appropriate devices. After period of adaptation (three weeks), half of the fish (24) were used as a control group while the other 24 were subjected to thermal stress by raising the water temperature to 29°C (10°C increase) in 60 min. In both control and thermally treated, fish blood was collected by heart puncture according to “Animal welfare act“. Analyses were performed with native blood, without addition of any anticoagulant and the values of red blood cell count (RBC), haemoglobin concentration, packed cell volume (PCV), Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Haemoglobin Concentration (MCHC) were determined. In the thermally treated fish, the values of PCV and MCV increased (p = 0.0003 and p = 0.0147 respectively), and those of MCHC decreased substantially (p = 0.0001).Keywords: Haematology, temperature, Barbus balcanicusAfrican Journal of Biotechnology Vol. 12(18), pp. 2484-249

Supplementary data for the article: Tripković, T.; Vasić, R.; Lolić, A.; Baošić, R. Determination of Metals in Artistic Pigments Using the Optimized GFAAS Method and Raman Spectroscopy. Chemical Papers 2022, n/a. https://doi.org/10.1007/s11696-022-02110-6.

Supplementary material for: [https://doi.org/10.1007/s11696-022-02110-6]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4948

Supplementary data for article: Tripkovic, T.; Charvy, C.; Alves, S.; Lolić, A.; Baošić, R.; Nikolić-Mandić, S. D.; Tabet, J. C. Identification of Protein Binders in Artworks by MALDI-TOF/TOF Tandem Mass Spectrometry. Talanta 2013, 113, 49–61. https://doi.org/10.1016/j.talanta.2013.03.071

Supplementary material for: [https://doi.org/10.1016/j.talanta.2013.03.071]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1366

Spektrofotometrijsko određivanje sadržaja kofeina u energetskim pićima i čajevima

Uvod: Kofein je prirodni alkaloid, izolovan iz više od 60 biljnih vrsta. Preko 80 % svetske populacije svakodnevno unosi kofein u organizam kroz konzumaciju kafe, čajeva, čokolade i, u poslednje vreme, energetskih pića. Ne treba zanemariti činjenicu da kofein, kao farmakološki aktivna supstanca, ulazi u sastav mnogih lekova koji se na tržištu Republike Srbije izdaju bez lekarskog recepta. Sem toga, kofein je psihoaktivni stimulans, blag je diuretik i pokazuje interakciju sa nekim lekovima usled indukcije CYP1 i CYP2 izoenzima, zbog čega je potrebno voditi računa o količini koja se unese u organizam. U skladu s tim, važno je i da sadržaj kofeina u energetskim pićima odgovara podacima koje proizvođači navode na deklaraciji. Cilj: Cilj ovog rada bio je spektrofotometrijsko određivanje sadržaja kofeina u uzorcima energetskih pića i čajeva proizvođača dostupnih na tržištu R. Srbije. Materijal i metode: Kofein je određivan metodom ultraljubičaste i vidljive (UV/VIS) spektrofotometrije u devet vrsta energetskih pića i po četiri uzorka crnog i zelenog čaja. Rezultati: U uzorcima energetskih pića određeni sadržaj kofeina je u opsegu od 26,81 do 35,44 mg/100 mL i u skladu je s deklarisanim sadržajem. Sadržaj kofeina u uzorcima čajeva varira u odnosu na vrstu (11,27-22,61 mg/100 mL zeleni i 13,85-22,73 mg/100 mL crni), ali je vezan i za poreklo, uslove gajenja i proces prerade čajeva. Zaključak: Ultraljubičasta i vidljiva spektrofotometrija se pokazala kao brza, precizna i jednostavna metoda za određivanje kofeina u energetskim pićima i čajevima. Imajući u vidu dobijene rezultate, važno je istaći da unos kofeina kroz uobičajenu dnevnu konzumaciju čajeva i energetskih pića ne bi trebalo da utiče negativno na zdravlje ljudi. Svakako treba imati u vidu da se ovaj alkaloid dodatno može uneti i putem drugih izvora, što je posebno važno za određene grupe pacijenata.Introduction: Caffeine is a natural alkaloid, isolated from more than 60 plant species. Over 80% of the world’s population consumes caffeine on daily basis through the consumption of coffee, tea, chocolates and, more recently, energy drinks. As a pharmacologically potent substance caffeine is an ingredient of many medicaments available on the pharmaceutical market of Republic of Serbia without a doctor’s prescription. Besides that, caffeine acts as a psychoactive stimulant, mild diuretic, and displays an interaction with some medicaments due to the induction of CYP1 and CYP2 isoenzymes. Keeping in mind all of the above, it is necessary to take into account the daily caffeine intake, as well as to control its content in energy drinks.Aim: The aim of this study was spectrophotometric determination of caffeine content in energy drinks and tea, available in markets of the Republic of Serbia. Material and Methods: Caffeine was determinated by UV/VIS spectrophotometry in nine types of energy drinks and eight samples of black and green tea. Results: The results showed that caffeine content in energy drink samples ranged from 26.81 to 35.44 mg/100mL and corresponds to declaration. The caffeine content in tea samples varies with the species (11.27-22.61 mg/100mL for green and 13.85-22.73 mg/100mL for black tea), but also with origin, growth conditions and tea processing.Conclusion: The obtained data suggest that UV/VIS spectrophotometry can be used for ro-utine determination and control of caffeine content in energy drinks and tea. It is important to note that caffeine intake through the usual daily consumption of tea and energy drinks should not have a negative impact on human health, but this alkaloid could be additionally consumed through other sources, which is especially important for certain groups of patients

Supplementary data for article: Paíga, P.; Lolić, A.; Hellebuyck, F.; Santos, L. H. M. L.; Correia, M.; Delerue-Matos, C. Development of a SPE-UHPLC-MS/MS Methodology for the Determination of Non-Steroidal Anti-Inflammatory and Analgesic Pharmaceuticals in Seawater. Journal of Pharmaceutical and Biomedical Analysis 2015, 106, 61–70. https://doi.org/10.1016/j.jpba.2014.06.017

Supplementary material for: [https://doi.org/10.1016/j.jpba.2014.06.017]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1674

Synthesis and Characterization of MnCo2O4 Porous Spinel Oxide

This work presents an investigation on spinel structured material that consist of Mn(II) and Co(II) combined in the formula MnCo2O4, where Mn(II) occupies tetrahedral and Co(II) octahedral sites of crystal structure. Such spinel structured material, MnCo2O4 was synthesized by citrate-gel combustion (CGC) technique, carefully chosen as the method of synthesis is very important for producing a material with desirable physico-chemical characteristics

DNA/BSA interactions and cytotoxic studies of tetradentate N,N,O,O-Schiff base copper(II) complexes: Scientific paper

Three Schiff base Cu(II) complexes, (N,N’-bis(acetylacetone)­propyl­enediimine)copper(II) complex, [Cu(acac2pn)] (1), (N,N'-bis-(ben­zoyl­acet­one)propylenediimine)copper(II) complex, [Cu(phacac2pn)] (2) and (N,N’-bis-(trifluoroacetylacetone)propylenediimine)­copper(II) complex, [Cu(tfacac2pn)] (3), were used to investigate the interactions with calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) using the electronic absorption and spectro­scopic fluorescence methods. UV–Vis absorption studies showed that studied complexes interact with DNA molecule and exhibit moderate binding affinity. Fluorescence studies of complexes 1–3 also showed a possibility for DNA int­ercalation as well as a relatively high binding ability toward BSA. Among the tested complexes, the highest affinity for DNA and BSA molecules was shown by complex 1. Cytotoxic analyses, performed on human colorectal carcinoma HCT-116 and healthy lung fibroblast MRC-5 cell lines, showed that complex 2 exhibited activity on both cell lines, while complexes 1 and 3 did not show any activity

Određivanje sadržaja nitrita i teških metala u mesu i proizvodima od mesa

Porast životnog standarda je znatno uticao na ishranu i proizvodnju hrane. Meso i mesne prerađevine su, zbog svoje visoke nutritivne vrednosti, značajan segment ljudske ishrane i bogat izvor elemenata u tragovima poput Fe, Zn, Mn, Ca, K, Mg, ali s druge strane, mogu akumulirati teške metale kao što su Cd i Pb. Toksične koncentracije metala u mišićima su retke, ali ih jetra i bubrezi akumuliraju. U industriji mesa, kao aditivi, važnu ulogu imaju nitriti, koji vremenom mogu preći u toksične i kancerogene nitrozamine što zavisi od pH, temperature, redoks potencijala kao i količine dodatih nitrita. U praćenju kvaliteta mesa i mesnih prerađevina, bitno je pratiti sadržaj metala, ali i rezidualne koncentracije nitrita. Cilj ovog rada je bio određivanje sadržaja Cd, Cu, Fe i Zn u uzorcima svinjskog i goveđeg mesa i svinjskoj džigerici, te sadržaja nitrita u uzorcima svinjskog i goveđeg mesa i mesnim prerađevinama – paštetama i kobasicama. Metali su određivani primenom metode ICP- AES, a nitriti standardnom metodom SRPS ISO 2918/1999. Sadržaj gvožđa u džigerici je 189,2 μg/kg, svinjskom i goveđem mesu 89,78 μg/kg, odnosno 87,79 μg/kg. Sadržaj Cu i Zn u svim ispitivanim uzorcima je u dozvoljenim granicama, a Cd se u uzorku svinjskog mesa nalazi 1,2 puta više nego što je dozvoljeno. Na osnovu dobijenih rezultata može se pretpostaviti da je inicijalno dodata količina nitrita u proizvodnom procesu bila u skladu sa zakonski definisanim ograničenjem