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Preparation of Proton Conducting Composite Membranes
from Sulfonated Poly(Ether Ether Ketone) and Silicotungstic Acid
-- Srinivasan Guhan and Dharmalingam Sangeetha
In this study, a series of composite membranes for Proton Exchange Membrane Fuel Cell (PEMFC)
were synthesized. PEMFCs are of much interest nowadays because of the features such as ease in setting up and low
temperature operation. Various properties of the composite membranes like ion exchange capacity, durability, tensile
strength, percentage elongation, and methanol permeability were studied. The thermal stability of the membrane was
analyzed using Thermogravimetric Analysis (TGA) technique. The structural characterization was done by Fourier
Transform Infrared (FT-IR) method. The X-ray Diffraction (XRD) analysis gave information about the crystallinity of
the composite. Methanol permeability was found to be decreasing with increase in the content of SWA, but
durability was decreasing. The mechanical properties were studied using universal testing machine. Both the tensile
property as well as percentage elongation decreased with increase in the content of Silicotungstic Acid (SWA). The
Dynamic Mechanical Analysis (DMA) was carried out to determine the Tg of the composite. The conductivity values
were determined by impedance spectroscopy. Durability was studied using Fenton's reagent.
© 2008 IUP . All Rights Reserved.
Identification and Simultaneous Separation of Six
Hydrophilic Therapeutic Vitamins by Micellar Thin Layer Chromatography
--Ali Mohammad and Sameen Laeeq
A novel micellar thin layer chromatographic method for simultaneous separation and on-plate
identification of B-group vitamins along with ascorbic and folic acids has been developed. A hybrid mobile phase
constituting a mixture of 4% aqueous Sodium Dodecyl Sulphate (SDS) + acetonitrile (1:2, v/v) was identified as the
most favorable for the resolution of multicomponent mixture of vitamins on silica high performance Thin
Layer Chromatography (TLC) plates (silica gel
60F4 catalog no. 1.05554, Merck, Germany). The resolved spots
were identified by visualization under ultraviolet radiation (l = 4) in a closed UV cabinet. The effects of type
of sample solvent, concentration of surfactant (SDS), volume ratio of acetonitrile in the mobile phase, and
the presence of essential amino acids in the sample have been examined. This method is simple, precise,
sensitive and useful for the analysis of vitamins
B1, B2, B6,
B12, ascorbic and folic acids present in marketed
pharmaceutical formulation.
© 2008 IUP . All Rights Reserved.
Interactions in Starch-Iodine Complex: Electrochemical and
Spectral Studies
--Kaushik Kundu and Kaushik Das
The interaction between starch and
I2 in aqueous medium in the absence of added
I_ has been investigated using Cyclic Voltammetry (CV) and visible absorption spectra.
The formation of the familiar blue
starch-I2 complex reduces the peak currents, indicating the complex to
be electrochemically inactive. The complex can be treated with an adsorption process that shows an
exponential growth, which is qualitatively analogous to a Type-III isotherm. The blue complex shows a broad
absorption band with maximum at ~600 nm, which is slightly blue-shifted at higher
I2 concentration. Apart from the blue complex, the evidence of the formation of another complex between uncharged
I2 and starch has been obtained from a shoulder at ~460-470 nm in the absorption spectrum that matches the absorption maximum of
I2 in aqueous medium. In the latter complex,
I2 retains its electrochemical activity and has a slightly less
positive redox potential than that of
I2/I_ couple.
© 2008 IUP . All Rights Reserved.
Chemical Speciation of Ternary Complexes of Calcium(II)
and Magnesium(II) with L-Glutamine and Succinic Acid
--Vajhala L S N Murthy, Kochu Govindan Sudarsan and Gollapalli Nageswara Rao
In this study, the chemical speciation of mixed ligand complexes of Ca(II) and Mg(II) with L-glutamine
and succinic acid was studied in varying compositions of Dimethyl Formamide (DMF) in aqueous
solution maintaining an ionic strength of 0.16 mol
L_1 (NaCl) at 303 K. The stability constants of ternary complexes
were refined with MINIQUAD75 using the primary alkalimetric data. The best-fit models were selected based
on statistical parameters and residual analysis. The extra stability of ternary complexes compared to their
binary analogues was believed to be due to electrostatic interactions of the side chains of ligands, charge
neutralization, chelate effect, stacking interactions and hydrogen bonding. The species distribution with pH at
different compositions of DMF and the plausible equilibria for the formation of species are discussed. The
probable structures of the complexes are also given. The bioavailability of the metal ions is explained based on
the speciation.
© 2008 IUP . All Rights Reserved.
IR and 13C NMR Spectral Correlations in Some Aryl Chalcones
--G Thirunarayanan, R Rajavel, G Vanangamudi, D Kamalakannan, N Kalyanasundaram and S Rohini
Infrared (IR) vCH and CH=CH (cm_1) out-of-plane stretching frequencies and 13C Nuclear Magnetic Resonance (NMR) chemical shifts (ppm) of
dCO data were assigned from their respective spectra of a series of various
substituted styryl biphenyl, thiophene and 9H-fluorenyl chalcones. These values were correlated with various Hammett
substituent constants. From the results of statistical analysis, the effect of substituents on the above frequencies can be explained.
© 2008 IUP . All Rights Reserved.
Taste-Masking and Development of Pediatric Formulation
of Nalidixic Acid
--Shishu and Kashyap N
Nalidixic acid, a widely used antibacterial drug, was bitter taste-masked and formulated into
child-friendly liquid oral suspension dosage form. Taste-masking was achieved using a pH sensitive polymer Eudragit
E-100 (aminoalkyl methacrylate copolymers). Solvent evaporation technique was used to prepare
taste-masked microspheres. A liquid oral suspension was prepared using taste-masked microspheres and was evaluated
for taste by panel testing and other parameters like drug content, viscosity, pH and resuspendability. Panel
testing data collected from 20 healthy volunteers indicate successful formulation of taste-masked liquid oral
suspension with excellent palatability and patient acceptability.
© 2008 IUP . All Rights Reserved.
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December'08
