DERIVITISATION OF PREGABALIN FOR SIMULTANEOUS ESTIMATION WITH METHYLCOBALAMINE USING ULTRAVIOLET SPECTROSCOPY

Accurate, sensitive, and economical procedures for simultaneous estimation of pregabalin and methylcobalamine in tablet dosage form have been developed. The method employed is simultaneous equation method. This method employs the formation and solving of simultaneous equation using 528 nm and 568 nm as the two wavelengths for forming equation. Drugs obey Beer’s law in the concentration range 10-50 µg mL-1 for pregabalin and 10-50 µg mL-1 for methylcobalamine. The proposed spectrophotometric method was validated and successfully applied for the assay of both drug combinations in several laboratory prepared mixtures and commercial tablets

Method Development for Leachable Furfural Determination in Wood-Based Panels by HPLC-Uv System

Analytical method has been developed and validated to determine free or leachable furfural concentration in wood-based panels. Particleboards obtained from birch wood and suberinic acids binder were chosen as a reference material. Two methods and two solvents were tested. Acetone extracts of the samples were analyzed with gas chromatography (GC) flame ionization detector system. Water extracts were analyzed with high-performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV) system. After the GC data in acetone extracts furfural concentration was below method limit of detection. HPLC-UV data showed that in water extracts furfural concentration was possible to determine. It was concluded that HPLC-UV is suitable and fast method for furfural determination in wood-based panels water extracts.

Construction and Properties of Ag-I Polymeric Clusters Attach With Nitrogen Heterocyclic Transition Metal Moiety

Two silver cluster compounds {[Co(1,10′-phen)3]2‧[Ag8I12]} (1) and {[Co(2, 2′-bipy)3]‧[Ag10I11]‧(OH)‧3DMF‧2H2O} (2) (1,10′-phen=1,10′-phenanthroline, 2, 2′-bipy=2,2′-bipyridine) were designed and synthesized by solvent evaporation method. The two silver cluster compounds were characterized by elemental analysis, infrared spectroscopy, ultraviolet spectroscopy, thermogravimetric analysis and X-ray powder diffraction. The crystal structures of compounds 1 and 2 were determined by X-ray crystallography diffraction. Through the electrostatic interaction between the metallic Ag cluster moiety and the metallic Co cluster moiety, form stable interlaced layered super molecular structures. In order to explore functional properties, the catalytic reduction of p-nitrophenol and electrochemical behavior of compounds 1 and 2 were explored. The results show that compounds 1 and 2 can efficiently catalyze the reduction of p-nitrophenol in the aqueous solution, and the reduction and removal rate can reach more than 90%.

Report on the Real Structure of Benzene Molecules and the Thickness of Graphene

The problem of the benzene molecular structure has not been solved for a long time. This research proposes a new concept of covalent bonds based on the existing theory: each electron shared by the nucleus corresponds to a half-valent bond, and a half-valent bond can be formed between interval carbon atoms of the benzene ring. A new theory was established. Quantum mechanical calculations results can quantitatively explain experimental results, such as the hydrogenation heat and ultraviolet spectroscopy of benzene. It has solved more than one hundred years of difficult problems. The design of the new structural forms of benzene molecules shows half-valent bonds with dotted lines, which have a wide range of adaptability, and shows the structural forms and reaction formulas of more than dozens of benzene homologs and derivatives. Under the guidance of the new theory, the stacked three-dimensional structure of benzene was explored. The thickness of the three-layer benzene tube is calculated to be almost equal to the thickness of the graphene. Therefore, it is speculated that graphene may be a three layer structure.

Ballistic ΔS=2 Intersystem Crossing in a Cobalt Cubane Following Ligand-Field Excitation Probed by Extreme Ultraviolet Spectroscopy

Femtosecond M2,3-edge X-ray absorption near-edge structure (XANES) spectroscopy is used to probe the excited-state dynamics of the cobalt cubane [CoIII4O4](OAc)4(py)4 (OAc = acetate, py = pyridine), a model for water oxidation catalysts. After ligand-field excitation, intersystem crossing to a metal-centered quintet occurs in 38 fs. 30% of the hot quintet undergoes ballistic back-ISC directly to the singlet ground stat, with the remainder relaxing to a long-lived triplet.