JSCS Vol 73, No. 6
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J. Serb. Chem. Soc. 73 (6) 597–607 (2008)
UDC *Sempervivum marmoreum
L.+66.061:615.28; JSCS–3742; doi: 10.2298/JSC0806597S; Original scientific paper
Comparative screening of the anti-oxidant and
antimicrobial activities of Sempervivum
marmoreum L. extracts obtained by various extraction techniques
SASA S. STOJICEVIC, IVANA T. STANISAVLJEVIC, DRAGAN T. VELICKOVIC*, VLADA B.
VELJKOVIC and MIODRAG L. LAZIC
Faculty of Technology, Bulevar oslobodjenja 124,
*Zdravlje-Actavis, Vlajkova 199, 16000
(Received 10 September, revised
This paper presents a comparative study of the
anti-oxidant and anti-microbial activities, total phenolic compounds and total
flavonoids in extracts obtained from houseleek (Sempervivum marmoreum L.) leaves by the classical (maceration),
ultrasonic and Soxhlet extraction (CE, UE and SE, respectively). The extract
obtained by the CE contained higher AMounts of phenolic and flavonoid compounds
and showed a better antioxidant activity than those obtained using other two
techniques. All the extracts, independent of the extraction technique applied,
showed antimicrobial activities against Aspergillus
Keywords: antimicrobial activity; anti-oxidant activity;
extraction; houseleek; Sempervivum
marmoreum L.; ultrasound.
Full Article
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J. Serb. Chem. Soc. 73 (6) 609–618 (2008)
UDC
599.735.5+591.436+66–946.1:591.478–035.57; JSCS–3743; doi:
10.2298/JSC0806609A;
Original scientific paper
Immobilization and characterization of bovine liver
catalase on eggshell
ÖZLEM ALPTEKİN, S. SEYHAN TÜKEL and DENİZ YILDIRIM
University of Çukurova, Faculty of Sciences and Letters, Department of
Chemistry, Adana 01330, Turkey
(Received 12 September, revised
Bovine liver catalase immobilized on eggshell
particles was characterized and the reusability of the immobilized catalase was
investigated in a batch type reactor. For immobilized catalase onto ground
eggshell (ICATG), the optimum initial AMount of catalase was 85 mg g-1
of eggshells, the optimum pH was 6.0 (75 mM citrate buffer) and the temperature
was 30 °C. The Vmax and Km values of ICATG were
determined as 29.1±1.2 U/mg of protein and 41.9±2.7 mM, respectively. The
reusability of ICATG was tested and the remaining activity of ICATG was found
to be 73 % of the initial activity after 80 cycles of batch operation. The
AMount of catalase bound onto the carrier was estimated by using the results of
induced coupled plasma measurements. The catalytic efficiencies (kcat/Km) of free catalase and ICATG were found to be 1.4´106 and 2.8´103 dm3 s-1 mol-1,
respectively. Catalase immobilization onto eggshell is economic and has good
reusability. Hence, it can be concluded that eggshell is an efficient carrier
for immobilizing catalase.
Keywords: catalase; eggshell; immobilization; glutaraldehyde;
induced coupled plasma.
Full Article - PDF 332 KB
J. Serb.
Chem. Soc. 73 (6) 619–630 (2008)
UDC 546.962+542.913:576+615.9;
JSCS–3744; doi: 10.2298/JSC0806619G; Original scientific paper
Synthesis, structural characterization
and cytotoxic activity of two new organoruthenium(II) complexes
SANJA GRGURIC-SIPKA, MOHAMED AL ARBI M. ALSHTEWI, DEJAN JEREMIC, GORAN N.
KALUDJEROVIC*, SANTIAGO GÓMEZ-RUIZ**, ZELJKO ZIZAK***, ZORICA JURANIC*** and
TIBOR J. SABO
Faculty of Chemistry,
*Department of Chemistry,
**DepartAMento de Química Inorgánica y
Analítica, E. S. C. E. T., Universidad Rey Juan Carlos, 28933 Móstoles, Madrid,
Spain
***
(Received 27 December 2007, revised
Two new
p-cymene ruthenium(II) complexes containing as additional ligands N-methylpiperazine ([(η6-p-cymene)RuCl2(CH3NH(CH2)4NH)]PF6,
complex 1) or vitAMin K3-thiosemicarbazone
([(η6-p-cymene)RuCl2(K3tsc)],
complex 2) were synthesized starting
from [(η6-p-cymene)2RuCl2]2
and the corresponding ligand. The complexes were characterized by elemental
analysis, IR, electronic absorption and NMR spectroscopy. The X-ray crystal
structure determination of complex 1
revealed “piano-stool” geometry. The differences in the cytotoxic activity of
the two complexes are discussed in terms of the ligand present.
Keywords:
ruthenium(II) complexes; p-cymene; K3-thiosemicarbazone;
N-methylpiperazine; cytotoxic
activity.
Full Article - PDF 406 KB
J. Serb. Chem. Soc. 73 (6) 631–639 (2008)
UDC
544.526.5+542.92+547.56:546.3–386+546.215; JSCS–3745; doi:
10.2298/JSC0806631L;
Original scientific paper
Photocatalytic degradation of Phenol Red
using complexes of some transition metals and hydrogen peroxide
SAVITRI LODHA, DIPTI VAYA, RAKSHIT AMETA and PINKI B. PUNJABI
Photochemistry and Solar Energy Laboratory, Department of Chemistry, University
College of Science, M. L. Sukhadia University, Udaipur – 313002, Rajasthan,
India
(Received 27 July, revised 20 December
2007)
The photocatalytic degradation of Phenol Red was
investigated using thiocyanate complexes of iron, copper, cobalt and hydrogen
peroxide. The rate of photocatalytic degradation of the dye was followed
spectrophotometrically. The effect of the variation of different parAMeters,
such as pH, concentration of the complexes and dye, AMount of H2O2
and light intensity on the rate of photocatalytic degradation was also studied.
A tentative mechanism for the photocatalytic degradation of Phenol Red is
proposed.
Keywords: photocatalytic degradation; Phenol Red; metal
complexes; hydrogen peroxide.
Full Article - PDF 285 KB
UDC
544.032.4:66.094.1:546.92+544.478+546.26; JSCS–3746; doi:
10.2298/JSC0806641E;
Original scientific paper
Temperature dependence of the kinetics of oxygen
reduction on carbon-supported Pt nanoparticles
NEVENKA R.
ELEZOVIC, BILJANA M. BABIC*, NEDELJKO V. KRSTAJIC**, SNEZANA LJ. GOJKOVIC** and
LJILJANA M. VRACAR**
Institute for Multidisciplinary
Research,
*Vinca Institute
of Nuclear Sciences,
**Faculty of
Technology and Metallurgy,
(Received 11 July, revised
The temperature dependence of oxygen
reduction reaction (ORR) was studied on highly dispersed Pt nanoparticles
supported on a carbon cryogel. The specific surface area of the support was 517
m2 g-1, the Pt particles diAMeter was about 2.7 nm and
the loading of the catalyst was 20 wt. %. The kinetics of the ORR at the Pt/C
electrode was exAMined in 0.50 mol dm-3 HClO4 solution in
the temperature range from 274 to 318 K. At all temperatures, two distinct E–log
j regions were observed; at low current densities with a slope of –2.3RT/F
and at high current densities with a slope of –2.3´2RT/F. In
order to confirm the mechanism of oxygen reduction previously suggested at a
polycrystalline Pt and a Pt/Ebonex nanostructured electrode, the apparent
enthalpies of activation at selected potentials vs. the reversible hydrogen
electrode were calculated in both current density regions. Although ∆Ha,1≠
> ∆Ha,h≠, it was found that the enthalpies
of activation at the zero Galvani potential difference were the sAMe and hence
it could be concluded that the rate-determining step of the ORR was the sAMe in
both current density regions. The synthesized Pt/C catalyst showed a small
enhancement in the catalytic activity for ORR in comparison to the
polycrystalline Pt, but no change in the mechanism of the reaction.
Keywords: oxygen reduction reaction; platinum catalyst;
carbon support; temperature dependence; enthalpy of activation.
Full Article - PDF 993 KB
J. Serb. Chem. Soc. 73 (6) 655–659 (2008)
UDC
543.551/.552+547–36:546.11'98+541.135.5; JSCS–3747;
doi: 10.2298/JSC0806655J; Short communication
Short communication
Coulometric–potentiometric determination of pKA of several organic bases
in propylene carbonate
LJILJANA N. JAKSIC and RADMILA M. DZUDOVIC*
Faculty of Mining and
Geology, University of Belgrade, Djusina 7, 11000 Belgrade
*Faculty of Sciences,
University of Kragujevac, Radoja Domanovica 12, 34000
(Received 30 November 2007, revised 4 February 2008)
The pKA
values of protonated triethylAMine, pyridine and 2,2'-dipyridyl in propylene
carbonate (PC) were determined by applying the coulometric––potentiometric
method and a hydrogen/palladium generator anode (H2/Pd). The
investigated and reference base were titrated to 50 % with protons
electrogenerated from hydrogen-saturated palladium, in the presence of sodium
perchlorate as the supporting electrolyte. The half-neutralization potentials E1/2(x) and E1/2(st.) of the investigated
and standard base, respectively, were measured using a glass–SCE pair. The
obtained pKA values were
compared with those reported in the literature.
Keywords: coulometry; pKA of
base; propylene carbonate; hydrogen/palladium electrode.
Full Article - PDF 234 KB
J. Serb. Chem. Soc. 73 (6) 661–664 (2008)
UDC 62–405.8.004.12:544.6–188; JSCS–3748; doi: 10.2298/JSC0806661P; Original
scientific paper
Supercapacitive characteristics of electrochemically active porous
materials
VLADIMIR V.
PANIC
Institute of
Chemistry, Technology and Metallurgy, Center for Electrochemistry, Njegoševa
12, 11000
(Received 27 March 2008)
The results of an investigation of the
capacitive characteristics of sol–gel-processed titanium- and carbon-supported
electrochemically active noble metal oxides, as representatives of porous
electrode materials, are presented in the lecture. The capacitive properties of
these materials were correlated to their composition, the preparation
conditions of the oxides and coatings, the properties of the carbon support and
to the composition of the electrolyte. The results of the electrochemical test
methods, cyclic voltAMmetry and electrochemical impedance spectroscopy, were
employed to resolve the possible physical structures of the mentioned porous
materials, which are governed by the controlled conditions of the preparation
of the oxide by the sol–gel process.
Keywords: porous electrodes; sol–gel procedure; oxide sols;
supercapacitors; dimensionally stable electrodes.
Full Article - PDF 243 KB
J. Serb. Chem. Soc. 73 (6)
665–671 (2008)
UDC 615.33:543.544.5:543–76; JSCS–3749; doi:
10.2298/JSC0806665M; Original scientific paper
A rapid and reliable determination
of doxycycline hyclate by HPLC with UV detection in pharmaceutical sAMples
Department of Chemistry,
Faculty of Natural Sciences and Mathematics, Visegradska 33, 18000
*D. D. ”Zdravlje–Actavis” –
Pharmaceutical and Chemical Company, 16000
(Received 14 September,
revised 7 November 2007)
An accurate, sensitive and reproducible
high performance liquid chromatographic (HPLC) method for the quantification of
doxycycline hyclate in pharmaceutical sAMples has been developed and validated.
The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm´4.6 mm, 10 mm particle size) at 20 °C
with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous
solution of oxalic acid (2:3:5, v/v/v). The flow rate was 1.25 ml min-1.
A UV detector set at 350 nm was used to monitor the effluent. Each analysis required
no longer than 4 min. The limits of detection and quantification were 1.15 and
3.84 μg ml-1, respectively. Recoveries for different concentrations
ranged from 99.58 to 101.93 %.
Keywords: high performance liquid chromatography;
doxycycline hyclate; ultraviolet detection.
Full Article - PDF 296 KB
J. Serb. Chem. Soc. 73 (6)
673–680 (2008)
UDC
553.492.004.54:504.53:58.051; JSCS–3750, doi:
10.2298/JSC0806673M; Original scientific paper
Methods for the
determination of the form of aluminium: Pseudogley soils
VESNA MRVIC, MIODRAG JAKOVLJEVIC*, DRAGI
STEVANOVIC*, DRAGAN CAKMAK and MIRJANA ZDRAVKOVIC
Institute of Soil Science,
Teodora Drajzera 7,
*Faculty of Agriculture, Nemanjina
6,
(Received 26 November 2007,
revised 18 March 2008)
Exchangeable aluminium (AlKCl)
and CaCl2-extractable aluminium (AlCaCl2) have approximately the
sAMe value in the prognosis of detrimental effect on plants. Additional, more
in-depth research should show which of the two applied methods of exchangeable
Al determination is more suitable (after Sokolov or using aluminon). The
contents of total Al and AMorphous Al increase with depth and percentage clay.
Crystalline Al oxides and CuCl2-extractable aluminium (AlCaCl2) and EDTA-extractable
aluminium (AlEDTA) represent the more mobile reserves of Al and they
depend mostly on changes in the acidity parAMeters of the soil. Exchangeable Al
is on average 4.3–4.7 times lower than the contents of AlCaCl2 and AlEDTA, 8
times lower than crystalline Al and 35 times lower than AMorphous Al. Some
methods are not sufficiently selective, hence further research is required to
achieve more favourable methods for the determination of the different forms of
Al.
Keywords: exchangeable Al; Al oxalate; Al dithionate; CuCl2
extractable Al; organic Al.
Full Article - PDF 459 KB
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Copyright
&AMp; copy; SHD 2008.
June 02, 2008.
For more information contact: JSCS@tmf.bg.ac.yu