Highly sensitive and selective spectrofluorimetric determination of metoclopramide hydrochloride in pharmaceutical tablets and serum samples using Eu3+ ion doped in sol-gel matrix.

A simple, sensitive and selective spectrofluorimetric method for the determination of Metoclopramide hydrochloride (MCP) is developed. The MCP can remarkably enhances the luminescence intensity of the Eu(3+) ion doped in sol-gel matrix at lambda(ex)=380 nm in DMSO at pH 8.7. The intensity of the emission band of Eu(3+) ion doped in sol-gel matrix increases due to energy transfer from MCP to Eu(3+) in the excited state. The enhancement of the emission band of Eu(3+) ion doped in sol-gel matrix at 617 nm was found to be directly proportional to the concentration of MCP with a dynamic range of 5 x 10(-9) - 1.0 x 10(-6) mol L(-1) and detection limit of 2.2 x10(-11) mol L(-1).

Novel spectrofluorimetric method for measuring the activity of the enzyme alpha-L-fucosidase using the nano composite optical sensor samarium(III)-doxycycline complex doped in sol-gel matrix.

A novel, simple, sensitive, and precise spectrofluorimetric method was developed for measuring the activity of the enzyme alpha-L-fucosidase (AFU). The method was based upon measuring the quenching of the luminescence intensity of the produced yellow colored complex ion associate of 2-chloro-4-nitrophenol [2-CNP] and a nano composite optical sensor samarium(III)-doxycycline [Sm(3+)-DC](+) complex in a sol-gel matrix at 645 nm. The remarkable quenching of the luminescence intensity of the [Sm(3+)-DC](+) complex doped in a sol-gel matrix by various concentrations of the reagent [2-CNP] was successfully used as an optical sensor for the assessment of AFU activity. The calibration plot was achieved over the concentration range 3.4 x 10(-9)-1.0 x 10(-6) mol L(-1) [2-CNP] with a correlation coefficient of 0.99 and a detection limit of 6.0 x 10(-10) mol L(-1). The method was used satisfactorily for the assessment of the AFU activity in a number of serum samples collected from various patients. A significant correlation between the luminescence activity of the enzyme AFU measured by the proposed procedure and the standard method was applied to patients and controls. The method proceeds without practical artifacts compared to the standard method.

Spectroscopic and electrochemical studies of ruthenium and osmium complexes of salicylideneimine-2-thiophenol Schiff base.

The reactions between [M(3)(CO)(12)], M = Ru and Os, and salicylideneimine-2-thiophenol Schiff base in THF under reflux gave [Ru(CO)(4)(satpH)] and [Os(CO)(3)(satpH(2))] complexes. Structures of the two complexes were proposed on the basis of spectroscopic studies. Magnetic study of [Ru(CO)(4)(satpH)] suggested that a change in oxidation state of the ruthenium atom from zero to +1 was achieved via oxidative addition of the SH group with a proton displacement to give a low-spin d(7) electronic configuration. UV-Vis spectra of the two complexes in different solvents exhibited visible bands due to metal-to-ligand charge transfer. Electrochemical investigation of the free ligand and complexes showed some cathodic and anodic irreversible peaks due to interconversions through electron transfer.