NOPR Collection:

Synthesis of a new cesium selective calix[4]arene based chromoionophore

Mon, 01 Dec 2003 00:00:00 GMT

Title: Synthesis of a new cesium selective calix[4]arene based chromoionophore Authors: Arora, V; Chawla, H M; Francis, T; Nanda, M; Singh, S P Abstract: A novel azo-pyridyl calix[4]arene, (5,11, 17,23-tetrakis(4'-azopyridyl)-25,26,27,28-tetrahydroxycalix[4]arene), has been synthesized in the 1,3-alternate conformation by coupling debutylated calix[4]arene with a diazotized solution of 4-aminopyridine. The synthesized chromoionophore gives a large bathochromic shift (119 nm) with an increase in the intensity of absorption on addition of a methanolic solution of CS₂CO₃. The selectivity coefficients for Cr³⁺ and Ni²⁺ has been determined to be K_cr³⁺, _C_s⁺ = 6.6 and K_Ni²⁺ , _C_s⁺ = 66, while other alkali and alkaline earth metal ions do not interfere. The synthesized calixarene derivative has the potential to be used for development of ionic filters. Page(s): 3041-3043

Microdetermination of anti-hypertensive drug Captopril using 2,6-dichlorophenol indophenol

Mon, 01 Dec 2003 00:00:00 GMT

Title: Microdetermination of anti-hypertensive drug Captopril using 2,6-dichlorophenol indophenol Authors: Srivastava, Ashutosh; Khare, Bindu; Argal, Rupali; Patel, Sandeep Abstract: A method has been developed for quantitative microdetermination of antihypertensive drug Captopril in vitro as well as in vivo samples, spectrophotometrically using 2,6-dichlorophenol indophenol [2 ,6-DCPIP). The sulphydryl moiety, of the Captopril is quantitatively oxidized to its corresponding [1,1'-dithiobis'(2-methyl-1-oxopropane-3,1 diyl)bis-L-proline]disulphide by 2,6-DCPIP exhibiting stoichiometry of 2:1. The reaction product has been characterized by FTIR and NMR spectral studies. The method is rapid, accurate with high precision and can be applied for determining drugs in pharmaceutical preparations as well as in-vivo samples. Page(s): 3036-3040

Ortho-substituted aniline-N-salicylidenes as corrosion inhibitors for zinc in sulphuric acid

Mon, 01 Dec 2003 00:00:00 GMT

Title: Ortho-substituted aniline-N-salicylidenes as corrosion inhibitors for zinc in sulphuric acid Authors: Desai, M N; Talati, J D; Shah, Neesha K Abstract: The corrosion of zinc in sulphuric acid containing different o-substituted aniline-N-salicylidenes has been studied with respect to inhibitor and acid concentration, period of exposure and temperature. All the five compounds studies show high (95-97%) inhibitive efficiency. At 0.5% inhibitor concentration in 0.5 M acid, the order of efficiency is: o-HNS (95.5%) < o- CNS (96.8%) < o-AnNS (99.7%) ≤ o-TNS (99.8%) ≤ ANS (99.9%). The activation energies are higher in inhibited than in uninhibited acid. It appears that an efficient inhibitor is characterized by a relatively greater decrease in the free energy of adsorption. Galvanostatic polarization studies indicate that these are mixed type inhibitors with predominant action on the local cathodes. Cathodic protection in the presence of these inhibitors has been studied. The inhibitors appear to function through adsorption due to the presence of the imine (-C=N-) group and conjugated double bonds. Page(s): 3027-3035

Determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxide by differential pulse anodic stripping voltammetry

Mon, 01 Dec 2003 00:00:00 GMT

Title: Determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxide by differential pulse anodic stripping voltammetry Authors: Sounderajan, Suvarna; Palrecha, M M Abstract: A simple and rapid differential pulse anodic stripping method for simultaneous determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxides is described. The most suitable supporting electrolyte is found to be 2M HCl. This method is suitable for the determination of Cd, Sb, Bi (0.1μg g^-1) , Cu(0.3μg g^-1) and Pb(0.5 μg g^-1) (with about 100mg as sample) with a relative standard deviation of 15-20%. Page(s): 3025-3026