NOPR Collection:http://nopr.niscpr.res.in/handle/123456789/179452026-10-09T14:20:59Z2026-10-09T14:20:59ZSpectrophotometric determination of hydroxylamine and its derivatives in drug formulations by the indophenol reactionDeepa, BNagaraja, K SBalasubramanian, Nhttp://nopr.niscpr.res.in/handle/123456789/179782016-07-20T04:23:55Z2006-04-01T00:00:00ZTitle: Spectrophotometric determination of hydroxylamine and its derivatives in drug formulations by the indophenol reaction
Authors: Deepa, B; Nagaraja, K S; Balasubramanian, N
Abstract: Hydroxylamine
has been determined by its reduction to ammonium sulphate in Zn/H<sub>2</sub>SO<sub>4</sub>
column and Berthelot reaction of the formed ammonium sulphate using salicylic
acid, sodium hypochlorite and sodium nitroprusside to give indophenol blue which
is measured spectrophotometrically at 648 nm. The molar absorptivity is found to
be 1.9×10<sup>4</sup> 1 mol<sup>-1</sup>cm<sup>-1</sup>. Beer's law is obeyed
in the range 2.5 - 25 μg
of hydroxylamine in 10 ml of its solution. For the
<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">determination of 1.5 μg/ml of hydroxylamine,
the RSD is 2.8% (n=10). The developed method has been applied for the determination
of hydroxylamine and its derivatives after hydrolysis in drug formulations. The
results obtained by the present method compare well with those obtained by the
available reference method and with the standard addition of hydroxylamine.</span>
Page(s): 913-9162006-04-01T00:00:00ZCatechol (l ,2-dihydroxybenzene) inside charged film on electrode surface— A new voltammetric sensor for vitamin CBhattacharjya, RimkiDas, Diganta Kumarhttp://nopr.niscpr.res.in/handle/123456789/179772016-07-20T05:57:22Z2006-04-01T00:00:00ZTitle: Catechol (l ,2-dihydroxybenzene) inside charged film on electrode surface— A new voltammetric sensor for vitamin C
Authors: Bhattacharjya, Rimki; Das, Diganta Kumar
Abstract: Catechol shows good reversible cyclic
voltammograms inside negative SDS, positive CTAB and zwitterionic phospholipid film
on glassy carbon disc electrode in tris buffer (<i>p</i>H 7.0). The mid point potential
values with respect to Ag-AgCl reference electrode are found to be +120 mV, +90
mV and +135 mV, respectively. While inside the SDS film, catechol interacts with
vitamin C in
solution and
the anodic current decreases with increasing concentration of vitamin C without
any change in cathodic peak current and position. Although no interaction with vitamin
C is observed when catechol is inside CTAB film, the mid-point potential of Catechol
inside lipid film is round to shift in negative
direction when
encapsulated in lipid film.
Page(s): 909-9122006-04-01T00:00:00ZA study on interaction between benzyl alcohol and cationic surfactant micelles by <sup>1</sup>H NMRWei, Xi-LianYin, Bao-LinCui, Ji-ChunLiu, JieSun, De-Zhihttp://nopr.niscpr.res.in/handle/123456789/179762016-07-20T06:16:52Z2006-04-01T00:00:00ZTitle: A study on interaction between benzyl alcohol and cationic surfactant micelles by <sup>1</sup>H NMR
Authors: Wei, Xi-Lian; Yin, Bao-Lin; Cui, Ji-Chun; Liu, Jie; Sun, De-Zhi
Abstract: Solubilization
of benzyl alcohol in aqueous micellar solution of 3-alkoxy-2-hydroxypropyl trimethyl
ammonium bromides (C<sub>n</sub>H<sub>2n+1</sub>OCH<sub>2</sub>CH(OH)CH<sub>2</sub>N(CH<sub>3</sub>)<sub>3</sub><sup>+</sup>
Br<sup>-</sup>, abbreviated as C<sub>n</sub>NBr, (<i>n</i>=8, 12, 14, 16) has been
studied by high resolution <sup>1</sup>H NMR. Results indicate that the alkyl chain
length of the surfactant affects the solubility of benzyl alcohol in the micellar
solution. The peak of methylenes in long chain surfactant splits into an upfield
signal and a down field signal when the solubilization system is at high
molar ratio of
benzyl alcohol to surfactant. The solubility of benzyl alcohol in micelle solutions
of different surfactants (<i>n</i>=8, 12, 14 and 16)at the same concentration
(3.00×10<sup>-2</sup>mol L<sup>-1</sup>) are 0.1125, 0.1470, 0.1755 and 0.2100 mol
L<sup>-1</sup>, respectively. The transfer free energy of benzyl alcohol from
aqueous phase to micellar phase is – 18.45, - 18.59, - 18.72 and - 18.80 kJ mol<sup>-1</sup>
for <i>n</i> = 8, 12, 14 and 16, respectively.
Page(s): 905-9082006-04-01T00:00:00ZKinetics and reactivity of indole-2,3 –dione ring towards alkali in dimethyl sulphoxide-water mixturesFathalla, Magda FIsmail, Amel Mhttp://nopr.niscpr.res.in/handle/123456789/179752016-07-20T04:25:39Z2006-04-01T00:00:00ZTitle: Kinetics and reactivity of indole-2,3 –dione ring towards alkali in dimethyl sulphoxide-water mixtures
Authors: Fathalla, Magda F; Ismail, Amel M
Abstract: Kinetics of alkaline
hydrolysis of indole-2,3 -dione (isatin) and indole-2,3-dione (N- melhyl isatin)
have been carried out at different percentages of DMSO-H<sub>2</sub>O mixtures and
at different temperatures in the range 30-45°C. The reaction proceeds according
to pesudo first-order kinetics. The presence of an electron releasing substituent
melhyl group attached to nitrogen atom accelerates the reaction rate. Thermodynamic
activation parameters ΔH<sup>#</sup>, ΔS<sup>#</sup><i> </i>and ΔG<sup>#</sup> have been determined.
The negative values of entropy of activation and the non- linear relation between
log rate constant and reciprocal of dielectric constant suggest selective solvation
by the higher polar water solvent molecules.
Page(s): 901-9042006-04-01T00:00:00Z