Girish Kumar,K; Saji John,Konnully; Remalakshmy,Poduval(Department of Applied Chemistry, April 2, 2005)
[+]
[-]
Abstract:
A set of six new polystyrene anchored metal
complexes have been synthesized by the reaction of the
metal salt with the polystyrene anchored Schiff base of
vanillin. These complexes were characterized by elemental
analyses, Fourier transform infrared spectroscopy, diffuse
reflectance studies, thermal studies, and magnetic susceptibility
measurements. The elemental analyses suggest a
metal : ligand ratio of 1 : 2. The ligand is unidentate and
coordinates through the azomethine nitrogen. The Mn(II),
Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic
while Zn(II) is diamagnetic. The Cu(II) complex is
assigned a square planar structure, while Zn(II) is assigned
a tetrahedral structure and Mn(II), Fe(III), Co(II), and Ni(II)
are all assigned octahedral geometry. The thermal analyses
were done on the ligand and its complexes to reveal their
stability. Further, the application of the Schiff base as a
chelating resin in ion removal studies was investigated. The
polystyrene anchored Schiff base gave 96% efficiency in the
removal of Ni(II) from a 20-ppm solution in 15 min, without
any interference from ions such as Mn(II), Co(II), Fe(III),
Cu(II), Zn(II), U(VI), Na , K , NH4
, Ca2 , Cl , Br , NO3
,
NO2
,and CH3CO2
. The major advantage is that the removal
is achieved without altering the pH.
Girish Kumar,K; Remalakshmy,Poduval; Sareena, John; Pearl,Augustine(Department of Applied Chemistry, May 11, 2006)
[+]
[-]
Abstract:
A new PVC membrane sensor, which is
highly selective towards Ni (II) ions, has been developed
using a thiophene-derivative Schiff base as the
ionophore. The best performance was exhibited by the
membrane having the composition percentage ratio of
5:3:61:31 (ionophore:NaTPB:DBP:PVC) (w=w), where
NaTPB is the anion excluder, sodium tetraphenylborate
and DBP is the plasticizing agent (dibutyl phthalate).
The membrane exhibited a good Nernstian response for
nickel ions over the concentration range of 1.0 10 1–
5.0 10 6M (limit of detection is 1.8 10 6 M) with a
slope of 29.5 1.0mV per decade of activity. It has a
fast response time of<20 s and can be used for a period
of 4 months with good reproducibility. The sensor is
suitable for use in aqueous solutions of a wide pH range
of 3.2–7.9. The sensor shows high selectivity to nickel
ions over a large number of mono-, bi- and trivalent
cations. It has been successfully used as an indicator
electrode in the potentiometric titration of nickel ions
against EDTA and also for direct determination of
nickel content in real samples – wastewater samples
from electroplating industries and Indian chocolates.
Girish Kumar,K; Remalakshmy,Poduval; Sareena, John; Pearl,Augustine(Departmenrt of Applied Chemistry, May 11, 2006)
[+]
[-]
Abstract:
A new PVC membrane sensor, which is
highly selective towards Ni (II) ions, has been developed
using a thiophene-derivative Schiff base as the
ionophore. The best performance was exhibited by the
membrane having the composition percentage ratio of
5:3:61:31 (ionophore:NaTPB:DBP:PVC) (w=w), where
NaTPB is the anion excluder, sodium tetraphenylborate
and DBP is the plasticizing agent (dibutyl phthalate).
The membrane exhibited a good Nernstian response for
nickel ions over the concentration range of 1.0 10 1–
5.0 10 6M (limit of detection is 1.8 10 6 M) with a
slope of 29.5 1.0mV per decade of activity. It has a
fast response time of<20 s and can be used for a period
of 4 months with good reproducibility. The sensor is
suitable for use in aqueous solutions of a wide pH range
of 3.2–7.9. The sensor shows high selectivity to nickel
ions over a large number of mono-, bi- and trivalent
cations. It has been successfully used as an indicator
electrode in the potentiometric titration of nickel ions
against EDTA and also for direct determination of
nickel content in real samples – wastewater samples
from electroplating industries and Indian chocolates.
Girish Kumar,K; Pearl,Augustine; Sareena, John; Beena,Saraswathyamma(Department of Applied Chemistry, June 12, 2006)
[+]
[-]
Abstract:
new PVC membrane ion selective electrode which is highly selective towards Ni(II) ions was constructed using a
Schiff base containing a binaphthyl moiety as the ionophore. The sensor exhibited a good Nernstian response for nickel
ions over the concentration range 1.0 × 10–1 – 5.0 × 10–6 M with a lower limit of detection of 1.3 × 10–6 M. It has a fast
response time and can be used for a period of 4 months with a good reproducibility. The sensor is suitable for use in
aqueous solutions in a wide pH range of 3.6 – 7.4 and works satisfactorily in the presence of 25% (v/v) methanol or
ethanol. The sensor shows high selectivity to nickel ions over a wide variety of cations. It has been successfully used as
an indicator electrode in the potentiometric titration of nickel ions against EDTA and also for the direct determination of
nickel content in real samples: effluent samples, chocolates and hydrogenated oils.
PVC supported liquid membrane and carbon paste potentiometric sensors incorporating an Mn(III)-porphyrin
complex as a neutral host molecule were developed for the determination of paracetamol. The measurements were
carried out in solution at pH 5.5. Under such conditions paracetamol exists as a neutral molecule. The mechanism of
molecular recognition between the Mn(III)-porphyrin and paracetamol, leading to potentiometric signal generation,
is discussed.The sensitivity and selectivity toward paracetamol of carbon paste and polymeric liquid membrane electrodes
incorporating an Mn(III)-porphyrin host were compared. The applicability of these sensors to the direct
determination of paracetamol was checked by performing a recovery test in human plasma.
Girish Kumar,K; Saji John,Konnully(Department of Applied Chemistry, August 1, 2006)
[+]
[-]
Abstract:
Salicylaldehyde Schiff base of amino-methylated
polystyrene has been developed as a novel reagent for the removal
of Fe(III) from solutions. The selectivity of the metal
ion uptake over a wide range of different concentrations of
metal ion, effect of pH, ligand concentration and the influence
of other foreign ions were studied. A very good selectivity
was achieved for the removal of the ion. It was found
that 0.01 g of the ligand was sufficient to achieve about 96%
removal of the metal ion in terms of concentration (ppm)
from a 30 ppm solution in acidic pH.
Girish Kumar,K; Muthuselvi,R(Department of Applied Chemistry, March 30, 2005)
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[-]
Abstract:
A spectrophotometric method employing 2-hydroxybenzaldiminoglycine (HBIG) is proposed for
the determination of chromium(III). The results of the determinations are compared with the standard diphenyl
carbazide method. The presently developed method is direct, simple, rapid, selective, sensitive and precise.
Girish Kumar,K; Devala Rao, G; Chowdary, K P R(Indian Journal Of Pharmaceutical Sciences, February 7, 2001)
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Abstract:
Two simple and sensitive spectrophotometric methods(A and B) in the visible region have been developed for the determination of cefotaxime sodium (DFTS) in bulk and in dosage forms. Method A is based on the reaction of CFTS with nitrous acid under alkaline conditions to form a stable violet colored chromogen with absorption maximum of 560 nm and method B is based on the reaction of CFTS with1,10-phenanthroline and ferric chloride to form a red colored chromogen with the absorption maximum of 520 mm.The color obeyed Beer’s law in the concentration range of 100-500 µg/ml for method A and 1.6-16 µg/ml for method B, respectively.When pharmaceutical preparations containing CFTS were analysed, the results obtained by the proposed methods are in good agreement with the labeled amounts and are comparable with the results obtained using a UV spectrophotometric method.
Girish Kumar,K; Karthikeyan, G; Mohanraj, K; Elango, K P(Pleiades, 2006)
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[-]
Abstract:
A series of nonelectrolytic lanthanide(III) complexes,
[
ML
2
Cl
3
]
·
2
H
2
O, where M is lanthanum(III),
praseodymium(III), neodymium(III), samarium(III), gadolinium(III), terbium(III), dysprosium(III), and
yttrium(III), containing sulfamethoxazole ligand (L) are prepared. The structure and bonding of the ligand are
studied by elemental analysis, magnetic susceptibility measurements, IR,
1
H NMR,
TG
/
DTA
, X-ray diffraction
studies, and electronic spectra of the complexes. The stereochemistry around the metal ions is a monocapped
trigonal prism in which four of the coordination sites are occupied by two each from two chelating ligands, sulfonyl
oxygen, and nitrogen of the amide group and the remaining three positions are occupied by three chlorines.
The ligand and the new complexes were tested in
vitro to evaluate their activity against the bacteria
Escherichia
coli
and
Staphylococcus
aureus.