Girish Kumar,K; Thomas, D; Joseph, R; Issac, S; Lonappan, L(The Institution of Engineering and Technology, October 10, 2011)
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Abstract:
A differential pulse voltammetric sensor for the determination of tamsulosin hydrochloride (TAM) using multiwalled carbon nanotubes
(MWNTs)–Nafion-modified glassy carbon electrode (GCE) has been developed. MWNTs were dispersed in water with the help of Nafion
and were used to modify the surface of GCE via solvent evaporation. At MWNT-modified electrode, TAM gave a well-defined oxidation
peak at a potential of 1084 mV in 0.1 M acetate buffer solution of pH 5. Compared to the bare electrode, the peak current of TAM
showed a marked increase and the peak potential showed a negative deviation. The determination conditions, such as the amount of
MWNT–Nafion suspension, pH of the supporting electrolyte and scan rate, were optimised. Under optimum conditions, the oxidation
peak current was proportional to the concentration of TAM in the range 1 × 1023 M–3 × 1027 M with a detection limit of
9.8 × 1028 M. The developed sensor showed good stability, selectivity and was successfully used for the determination of TAM in pharmaceutical
formulations and urine samples
Girish Kumar,K; Pearl, Augustine; Sareena, John(Springer, August 29, 2009)
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Abstract:
The fabrication and electrochemical response
characteristics of two novel potentiometric sensors for the
selective determination of domperidone (DOM) are described.
The two fabricated sensors incorporate DOM–PTA
(phosphotungstic acid) ion pair as the electroactive material.
The sensors include a PVC membrane sensor and a carbon
paste sensor. The sensors showed a linear, stable, and near
Nernstian slope of 56.5 and 57.8 mV/decade for PVC
membrane and carbon paste sensors, respectively over a
relatively wide range of DOM concentration (1.0 9
10-1–1.0 9 10-5 and 1.0 9 10-1–3.55 9 10-6 M). The
response time of DOM–PTA membrane sensor was less than
25 s and that in the case of carbon paste sensor was less than
20 s.Auseful pH range of 4–6 was obtained for both types of
sensors. A detection limit of 7.36 9 10-5 M was obtained
for PVC membrane sensor and 1.0 9 10-6 M was obtained
for carbon paste sensor. The proposed sensors showed very
good selectivity toDOMin the presence of a large number of
other interfering ions. The analytical application of the
developed sensors in the determination of the drug in pharmaceutical
formulations such as tablets was investigated.
The results obtained are in good agreement with the values
obtained by the standard method. The sensors were also
applied for the determination ofDOMin real samples such as
urine by the standard addition method.
Description:
J Appl Electrochem (2010) 40:65–71
DOI 10.1007/s10800-009-9975-2
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.
Girish Kumar,K; Joseph, Renjini(Taylor & Francis, June 1, 2009)
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[-]
Abstract:
A metalloporphyrin incorporated carbon paste sensor has been developed
for the determination of metronidazole benzoate (MTZB). Zn(II) complex
of 5,10,15,20-tetrakis (3-methoxy-4-hydroxy phenyl) porphyrin (TMHPP) was
used as the active material. The MTZB gave a well-defined reduction peak at
- 0.713V in 0.1 mol l -1 phosphate buffer solution of pH around 7. Compared
with bare carbon paste electrode (CPE), the TMHPP Zn(II) modified electrode
significantly enhanced the reduction peak current of MTZB as well as lowered
its reduction potential. Under optimum conditions the reduction peak current
was proportional to MTZB concentration over the range 1×10-3 mol1-1 to 1×10-5mol1-1. The detection limit was found to be 4.36×10-6mol1-1
. This
sensor has been successfully applied for the determination of MTZB in pharmaceutical
formulations and urine samples.
Dipyrromethene-Cu(II) derivatives possessing two dodecane alkyl chains have been used for the modification of gold
electrodes. Electroactive host molecules have been incorporated into a lipophilic dodecanethiol SAM deposited onto
gold electrodes through hydrophobic and van der Waals interactions (embedment technique). The presence of
dipyrromethene-Cu(II) redox centers on the electrode surface was proved by cyclic voltammetry and Osteryoung
square-wave voltammetry. The Au electrodes incorporating redox active Cu(II)-dipyrromethene SAMs were used for
the direct voltammetric determination of paracetamol in human plasma.