J. Serb. Chem. Soc. 74 (10) 1021–1033 (2009)
UDC 541.135.5–039.26:543.55:681.586.000.57; JSCS–3896; doi: 10.2298/JSC0910021V; Authors’ review

Authors’ review

Carbon paste electrodes in electroanalytical chemistry
KAREL VYTŘAS, IVAN ŠVANCARA AND RADOVAN METELKA

Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, CZ – 532 10 Pardubice, Czech Republic

(Received 17 April 2009)

An overview is given dealing with the applications of carbon paste electrodes in equilibrium potentiometry as well as in electrochemical stripping analysis using both voltAMmetric and potentiometric modes. Various modifications of carbon pastes and carbon paste-based biosensors are also mentioned. The main emphasis in this article is directed at summarizing recent results of the authors’ research group during the past few years.

Keywords: carbon paste electrodes; potentiometry; electrochemical stripping analysis; flow injection analysis; electrode modification; heavy metals determination; biosensors.

J. Serb. Chem. Soc. 74 (10) 1035–1040 (2009)
UDC 582.475.2:665.52/.54:615.282–188(497.11); JSCS–3897; doi: 10.2298/JSC0910035T; Original scientific paper

Chemical composition and antifungal activity of the essential oil of Douglas fir (Pseudosuga menziesii Mirb. Franco) from Serbia
VELE TEŠEVIĆ, SLOBODAN MILOSAVLJEVIĆ, VLATKA VAJS*, IRIS ĐORĐEVIĆ**, MARINA SOKOVIĆ***, VERA LAVADINOVIĆ**** and MIROSLAV NOVAKOVIĆ*
Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia

*Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

**Faculty for Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000 Belgrade, Serbia

***Institute for Biological Research “S. Stanković”, University of Belgrade, Bulevar despota Stefana 142, 11000 Belgrade, Serbia

****Institute of Forestry, Kneza Višeslava 3, 11030 Belgrade, Serbia

(Received 25 February, revised 8 April 2009)

The chemical composition of the essential oil of fresh young needles with twigs of Douglas fir (Pseudosuga menziesii Mirb. Franco) obtained by hydrodistillation were analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). Ten compounds, accounting for 94.26 % of the oil, were identified. The main compounds found were bornyl acetate (34.65 %), cAMphene (29.82 %), a-pinene (11.65 %) and santene (5.45 %). The antifungal activity of the essential oil was tested against various fungal species. The minimum inhibitory concentration of Douglas fir essential oil ranged from 1.5 to 4 µg mL^-1. The fungi most sensitive to the tested oil were Phomopsis helianthi, while Penicillium species, along with Microsporum canis, were the most resistant. Compared to the commercial fungicidal agent bifonazole, the studied essential oil demonstrated higher antifungal activity.

Keywords: antifungal activity; bornyl acetate; Douglas fir; essential oil.

J. Serb. Chem. Soc. 74 (10) 1041–1049 (2009)
UDC 547.79+66.095.253:615.281–188; JSCS–3898; doi: 10.2298/JSC0910041B;  Original scientific paper

New S-alkylated 1,2,4-triazoles incorporating diphenyl sulfone moieties with potential antibacterial activity
STEFANIA F. BARBUCEANU, GABRIELA L. ALMAJAN, IOANA SARAMET, CONSTANTIN DRAGHICI*, RADU SOCOTEANU** and FLORICA BARBUCEANU***

Carol Davila University of Medicine and Pharmacy, Faculty of Pharmacy, Organic Chemistry Department, Traian Vuia Street 6, 020956, Bucharest, Romania

*C. D. Neniţescu Institute of Organic Chemistry, Romanian Academy, Splaiul Independenţei 202B, 060023, Bucharest, Romania

**I. G. Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 77208, Bucharest, Romania

***Institute for Diagnosis and Animal Health, Dr. Staicovici Street 63, 050557, Bucharest, Romania

(Received 29 January, revised 22 April 2009)

Alkylation of the 5-{4-[(4-bromophenyl)sulfonyl]phenyl}-4-(3/4-me¬thylphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones 3a,b with various alkylation agents, i.e., ethyl bromide, phenacyl bromide and ethyl chloroacetate, afforded the S-substituted 1,2,4-triazoles 4-6a,b. The structures of these new compounds were elucidated by elemental analysis and IR, UV, ¹H-NMR, ¹³C-NMR and MS spectroscopy. The newly synthesized products were tested for their antibacterial effects.

Keywords: alkylation; 1,2,4-triazole-3-thione; antibacterial activity.

J. Serb. Chem. Soc. 74 (10) 1051–1061 (2009)
UDC 547.861.3+547.53.024:544.147.4; JSCS–3899; doi: 10.2298/JSC0910051Z; Original scientific paper

The influence of dispersive interactions on the binding affinities of ligands with an arylpiperazine moiety to the dopAMine D2 receptor
MARIO V. ZLATOVIĆ, VLADIMIR V. ŠUKALOVIĆ*, GORAN M. ROGLIĆ, SLAĐANA V. KOSTIĆ-RAJAČIĆ* and DEANA B. ANDRIĆ
Faculty of Chemistry, University of Belgrade, P.O. Box 51, 11158 Belgrade, Serbia

*ICTM, Department of Chemistry, University of Belgrade, P.O. Box 473, 11001 Belgrade, Serbia

(Received 17 February, revised 21 April 2009)

Several isosteric 1,3-dihydro-5-[2-(4-aryl-1-piperazinyl)ethyl]-2H-benzimidazole-2-thiones were used to investigate the interactions of different ligands with the binding site of the D2 receptor. Due to limitations of the simulation methods, docking analysis failed to show precisely the interactions that influence the binding affinity of the ligands. It is presumed that dispersive forces or more precisely edge-to-face interactions play an important role in the binding process, especially for the lipophilic part of the ligands. In order to confirm this hypothesis, ab initio calculations were applied on a model system in order to find the stabilization energies of potential edge-to-face interactions and then to correlate them with the ligand affinity. The obtained results indicate that there is a significant correlation between the strength of dispersive inter-actions and ligand affinity. It was shown that for the calculation of stabilization energies of modeled receptor–ligand complexes the Becke “half-and-half” hybrid DFT method can be used, thus speeding up the usually long calculation time and reducing the required computer strength.

Keywords: dispersive interactions; hybrid DFT; ligand affinity; correlation; D2.

J. Serb. Chem. Soc. 74 (10) 1063–1073 (2009)
UDC *atorvastatin:612.111:66.094.3.097.8; JSCS–3900; doi: 10.2298/JSC0910063N; Original scientific paper

J. Serb. Chem. Soc. 74 (10) 1075–1084 (2009)

J. Serb. Chem. Soc. 74 (10) 1085–1096 (2009)

UDC 547.575+546.962+542.913; JSCS–3902; doi: 10.2298/JSC0910085K; Original scientific paper

J. Serb. Chem. Soc. 74 (10) 1097–1104 (2009)

UDC 547.979.733+54–386–034:543.57:532.783; JSCS–3903; doi: 10.2298/JSC0910097Z; Original scientific paper

An unsymmetrical porphyrin and its metal complexes: synthesis, spectroscopy, thermal analysis and liquid crystal properties

CHANGFU ZHUANG, XUEXIN TANG, DONG WANG, AIQING XIA, WENHUI LIAN, YUHUA SHI and TONGSHUN SHI

College of Chemistry, Jilin University, Changchun 130023, P. R. China

(Received 25 January, revised 30 April 2009)

The synthesis and characterization of a new unsymmetrical porphyrin liquid crystal, 5-(4-stearoyloxyphenyl)phenyl-10,15,20-triphenylporphyrin (SPTPPH₂) and its transition metal complexes (SPTPPM, M(II) = Zn, Fe, Co, Ni, Cu or Mn) are reported. Their structure and properties were studied by elemental analysis, and UV–Vis, IR, mass and ¹H-HMR spectroscopy. Their luminescent properties were studied by excitation and emission spectroscopy. The quantum yields of the S1 ® S0 fluorescence were measured at room temperature. According to thermal studies, the complexes have a higher thermal stability (no decomposition until 200 °C). Differential scanning calorimetry (DSC) data and an optical textural photograph, obtained using a polarizing microscope (POM), indicate that the porphyrin ligand had liquid crystalline character and that it exhibited more than one mesophase and a low-lying phase transition temperature, with transition temperatures of 19.3 and 79.4 °C; the temperature range of the liquid crystal (LC) phase of the ligand was 70.1 °C.

Keywords: porphyrin; transition metal complex; fluorescence spectroscopy; liquid crystal.

J. Serb. Chem. Soc. 74 (10) 1105–1111 (2009)   

UDC 547.16–386.004.12:541.001.5; JSCS–3904, doi: 10.2298/JSC0910105G; Original scientific paper

Theoretical insights into the properties of the borazine×××X^– complexes (X^– = H, F, Cl, CN, NC or NCO)

REZA GHIASI

Department of Chemistry, East Tehran Branch (QiAM Dasht) – IslAMic Azad University, Tehran, Iran

(Received 20 February, revised 12 March 2009)

The character of the NH×××X^- (X^- = H, F, Cl, CN, NC or NCO) in-teractions of borazine with anions was studied using ab initio method. The interaction energies were calculated at the B3LYP/6-311++G(d,p) level. The energetic and geometric characteristics of the complexes were compared. The “atoms in molecules” methodology was used to analyze the electron density and to obtain atomic contributions to the total energy and charge of the systems. Natural bond orbital (NBO) analysis demonstrated the charge transfer in the study of the nature of the intermolecular interactions. The aromaticity of these compounds was predicted in light of the nucleus-independent chemical shift (NICS).

Keywords: borazine; borazine complexes; interaction energy; NBO; AIM methodology.

J. Serb. Chem. Soc. 74 (10) 1113–1123 (2009)

UDC 546.922+66.022.4+661.183.6+544.35+661.727.4; JSCS–3905; doi: 10.2298/JSC0910113M; Original scientific paper

The use of NaX zeolite as a template to obtain a mono-atomic Pt dispersion by impregnation with Pt(II) acetylacetonate/acetone solution

SLAVKO MENTUS, ZORICA MOJOVIĆ* and VELIMIR RADMILOVIĆ**

University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12, 11000 Belgrade, Serbia

*ICTM – Department for Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade, Serbia

**National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, University of California, Berkeley, USA

(Received 26 October 2008, revised 11 June 2009)

The incorporation of platinum into the cavities of NaX zeolite was realized by impregnation and thermal decomposition of the organometallic compound Pt(II)-acetylacetonate dissolved in acetone. A high dispersion of platinum to predominantly mono-atomic particles was achieved thanks to the tight fit of the Pt(II)-acetylacetonate molecules in the aperture of the zeolite supercage. Using the high angle annular dark field imaging technique of HRTEM, individual Pt particles situated within the zeolite crystals were, for the first time, clearly visible. This offers new possibilities of studying the distribution of incorporated metal particles along the crystal depth.

Keywords: HRTEM imaging; impregnation technique; NaX zeolite; Pt(II)-acetylacetonate; platinum-modified zeolite.

J. Serb. Chem. Soc. 74 (10) 1125–1132 (2009)

UDC 546.26–037.6:54–78:541.183; JSCS–3906 doi: 10.2298/JSC0910125S; Original scientific paper

The effect of gAMma radiation on the properties of activated carbon cloth

DANIJELA R. SEKULIĆ, BILJANA M. BABIĆ, LJILJANA M. KLJAJEVIĆ, JELENA M. STAŠIĆ and BRANKA V. KALUDJEROVIĆ

“Vinča” Institute of Nuclear Sciences, Laboratory for Materials Science, P.O. Box 522, 11001 Belgrade, Serbia

(Received 23 February, revised 9 April 2009)

Activated carbon cloth dressing is an appropriate wound healing material due to its biocompatibility and adsorption characteristics. The in-fluence of gAMma radiation as a sterilization process on the adsorption and mechanical properties of activated carbon cloth was investigated. The specific surface area, micropore volume, pore size distribution, surface chemistry as well as the breaking load of activated carbon cloth before and after gAMma radiation were exAMined. Characterization by nitrogen adsorption showed that the activated carbon cloth was a microporous material with a high specific surface area and micropores smaller than 1 nm. GAMma radiation decreased the specific surface area and micropore volume but increased the pore width. The sterilization process changed the surface chemistry quantitatively, but not qualitatively. In addition, the breaking load decreased but without any influence considering the further application of this material.

Keywords: activated carbon cloth; dressing material; gAMma radiation; adsorption; surface modification.

J. Serb. Chem. Soc. 74 (10) 1133–1142 (2009)

UDC 546.59+66.061+547.633.6’491.4’581.2+543.4/.5; JSCS–3907; doi: 10.2298/JSC0910133H; Original scientific paper

Solid phase extraction and a spectrophotometric method for the determination of trace AMounts of gold with 4-rhodanineazo benzoic acid

ZHANG JIE HUANG, XIAO GUO WANG and JUN ZHANG

Department of Chemistry, Yunnan University, Kunming, 650091, P. R. China

(Received 19 January, revised 18 May 2009)

The synthesis and application of 4-rhodanineazo benzoic acid (4-BARA) as a new chromogenic reagent for the determination of gold is described. A highly sensitive, selective, and fast method for the determination of gold based on its rapid reaction with 4-rhodanineazo benzoic acid and the solid phase extraction of the colored complex on a reversed phase Clean-up^® C5 cartridge was developed. In the presence of 0.02–0.2 mol/L phosphoric acid solution and a polyoxyethylene nonylphenol ether (emulsifier-OP) medium, 4-rhodanineazo benzoic acid reacted with gold to form a colored complex with a gold-to-4-BARA molar ratio of 1:2. The complex was enriched by solid phase extraction with a reversed phase Clean-up^® C₅ cartridge. The complex was eluted from the cartridge with ethanol and an enrichment factor of 50 was achieved. In ethanol medium, the molar absorptivity of the complex was 2.39×105 L mol^-1 cm^-1 at 505 nm. The Beer Law was obeyed in the concentration range 0.01–~1.2 µg/mL. The relative standard deviation for eleven replicate sAMples at the 0.001 µg/mL level was 2.3 %. In the original sAMple, the detection limit was 8.0×10^-5 µg/mL. This method was applied to the determination of trace AMounts of gold in ore sAMples with good result.

Keywords: 4-rhodanineazo benzoic acid; gold; spectrophotometry; solid phase extraction.

J. Serb. Chem. Soc. 74 (10) 1143–1153 (2009)

UDC *digoxin:661.12.002.8:615:62–776; JSCS–3908; doi: 10.2298/JSC0910143T; Original scientific paper

Validation of an HPLC–UV method for the determination of digoxin residues on the surface of manufacturing equipment

ZORAN B. TODOROVIĆ, MIODRAG L. LAZIĆ, VLADA B. VELJKOVIĆ and DRAGAN M. MILENOVIĆ*

Faculty of Technology, Bulevar oslobođenja 124, 16000 Leskovac, University of Niš, Serbia

*Zdravlje-Actavis Company, Analytical Department, Vlajkova 199, 16000 Leskovac, Serbia

(Received 25 February, revised 15 May 2009)

In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace AMounts of drugs have, therefore, to be considered with special attention. An HPLC–UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD), were below 6.3 %. The method was validated over a concentration range of 0.05–12.5 µg mL^-1. Low quantities of drug residues were determined by HPLC–UV using a Symmetry C18 column (150´4.6) mm, 5 µm) at 20 °C with an acetonitrile–water (28:72, v/v) mobile phase at a flow rate of 1.1 mL min^-1, an injection volume of 100 µL and were detected at 220 nm. A simple, selective and sensitive HPLC–UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied.

Keywords: cleaning validation; digoxin; swab analysis; residues.

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