Preparation and characterization of in situ carbon paste and screen-printed potentiometric sensors for determination of econazole nitrate: surface analysis using SEM and EDX

The construction and performance characteristics of new sensitive and selective in situ carbon paste (ICPE) and screen-printed (ISPE) potentiometric sensors modified with ion-pairing agents such as phosphotungstic acid, sodium tetraphenylborate, phosphomolybdic acid and ammonium reineckate for determination of econazole nitrate (ECN) have been developed. The reaction mechanism between ECN and ion-pairing agents at the electrode surface was studied through scanning electron microscope and energy-dispersive X-ray analysis. The electrodes under investigation showed potentiometric response for ECN in the concentration range from 1.0 × 10^?6 to 5.0 × 10^?3 mol L^?1 and from 1.0 × 10^?6 to 1.0 × 10^?2 mol L^?1 for ISPE (electrode I) and ICPE (electrode II) potentiometric sensors, respectively, at 25 °C. The electrode response was pH independent in the range 2.5–7.5 and 2.5–6.5 for electrodes I and II, respectively. These sensors have Nernstian slope values of 59.4 ± 0.2 and 59.10 ± 0.2 mV decade^?1 with detection limit of 1.0 × 10^?6 mol L^?1 for electrodes I and II, respectively. The electrodes showed fast response time of 4 and 9 s for electrodes I and II, respectively. The ISPE (electrode I) showed lifetime of 28 days, and this was considered as advantage over ICPE (electrode II). Selectivity for ECN with respect to a number of interfering materials was also investigated. The proposed electrodes were applied for determination of ECN in pure and pharmaceutical formulation using calibration, potentiometric titration and standard addition methods. The results showed good agreement with those obtained using official method. The t and F values indicated no significant difference between the suggested and reported methods. Method validation parameters were optimized according to ICH recommendations.     

Surface modification of Makrofol-DE induced by α-particles

In the present work, Makrofol DE samples were irradiated with different doses of alpha particles. The optical and mechanical modifications in the alpha-irradiated Makrofol samples as a function of alpha irradiation time have been investigated. Different characterization techniques, UV–vis spectroscopy, photoluminescence spectroscopy and Vickers micro hardness tester have been used. UV–vis spectra of bombarded samples reveal that the optical absorption increases with increasing the irradiation time. The direct and indirect optical band gap was found to decrease from 3.4 and 2.81?eV for pristine sample to 3.1 and 2.35?eV for that bombarded with alpha particles at the highest irradiation time (15?h), respectively. The number of carbon atoms per conjugated length (N) and the number of carbon atoms per cluster (M) have been estimated. An increase in both N and M with increasing the irradiation time was noticed. A remarkable decrease in PL intensity with increasing the alpha irradiation time was observed. This decrease is attributed to ion beam-induced change in molecular structure and/or defects in the modified layer. The surface hardness for unmodified and modified polymeric material has been studied.     

Reactions of Aroylhydrazones,IV: Synthesis of Nitrogen Heterocycles from Opianic Acid Hydrazones

Opianic acid reacts with various hydrazines to yield either hydrazone ( 3, 6 ) or phthalazinone ( 4 ) derivatives depending upon the electronic properties of the substituent attached to the hydrazine molecule. Oxidative cyclization of opianic acid aroylhydrazones with iodine and yellow mercuric oxide gave the 1,3,4-oxadiazole derivatives 21 . The aroylhydrazones were also condensatively cyclized by heating with acetic anhydride to give the 1,3,4-oxadiazoline derivatives 24 . Structures assigned to the prepared compounds were corroborated by studying their chemical as well as their spectral characteristics.     

Search for isovector giant monopole resonances via the Pb(3He,tp) reaction

The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45相似文献