Dissociation Constants of Some Isomeric Aminoquinolines: Determination of the Site of Protonation from Shifts in Electronic Absorption Spectra

1971 ◽  
Vol 60 (3) ◽  
pp. 371-374 ◽  
Author(s):  
S.G. Schulman
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Dissociation Constants ◽  
Electronic Absorption Spectra

scholarly journals Luminescent determination of residues of trazodon hydrochloride and melatonin after cleaning pharmaceutical equipment

2019 ◽  
pp. 73-81
Author(s):  
O. D. Voitiuk ◽  
A. V. Yegorova ◽  
Yu. V. Scrypynets ◽  
S. N. Kashutskуy ◽  
V. P. Antonovich
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Xenon Lamp ◽  
Excitation Spectra ◽  
Absorption Bands ◽  
Limit Of Quantitation ◽  
Trazodone Hydrochloride

A prerequisite for ensuring the quality of medicines is their production in accordance with the rules of GMP (Good Manufacturing Practice for Medicinal Products), one of the most important requirements of which is equipment cleaning. In many cases, the same equipment is used in the production of various preparations. Therefore, to prevent contamination of each of the following drugs, the previous one, it is very important to carry out an effective equipment cleaning procedure with a mandatory assessment of its purity. The purpose of this study was to develop simple, express, selective methods for luminescent determination of residual quantities of APIs of trazodone hydrochloride (TG) and melatonin (MT) in washes to control the completeness of their removal when cleaning process equipment. The excitation and luminescence spectra were recorded using a Cary Eclipse "Varian" spectrofluorimeter (Australia) with a xenon lamp 150 W. Electronic absorption spectra were recorded on a UV-2401 PC spectrophotometer «Shimadzu» (Japan). The electronic absorption spectra of TG and MT have absorption bands in the UV spectral region. It was established experimentally that the excitation spectra of TG and MT are similar to their absorption spectra (λex = 318 nm (TG) and λem = 274 nm (MT)). The effect on the luminescence intensity of TG and MT of methanol, ethanol, acetonitrile, dimethylformamide, dimethylsulfoxide, propanol (50 v/v) was studied. It is established that the maximum luminescence is observed in water. The methods were validated according to the following parameters: specificity, linearity, accuracy, limit of quantitation. The degree of extraction of trazodone hydrochloride and melatonin from applicators and surfaces of pharmaceutical equipment is more than 90%. The developed methods can be recommended for determining the residual amounts of trazodone hydrochloride and melatonin while monitoring the quality of the cleaning of pharmaceutical equipment.

Determination of photoredox properties of individual kinetically labile complexes in equilibrium systems

2011 ◽  
Vol 65 (5) ◽  
Author(s):  
František Šimo ◽  
Jozef Šima
Keyword(s):  
Quantum Yield ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Individual Species ◽  
Yield Values ◽  
Photochemical Properties ◽  
Species Being

AbstractThe paper evaluates the possibilities and limitations in characterising photochemical properties of individual kinetically labile species being in mutual equilibrium. A model of calculating quantum yield values is elaborated and applied to azidokojic iron(III) complexes in aqueous solutions. Based on the known speciation of the complexes as a function of pH, Fe(III) and azidokojic acid concentrations, electronic absorption spectra of individual species, and the determined overall quantum yield of Fe(II) photoformation at irradiation with monochromatised radiation at 366 nm, the quantum yield of Fe(III) to Fe(II) photoreduction was obtained for each of the complexes present in the investigated systems.

Dithiolate Mixed with Diimine and it's Metal Effects on Sensors

2014 ◽  
Vol 1021 ◽  
pp. 52-55
Author(s):  
Yong Hui Jia ◽  
Chao Xu
Keyword(s):  
Energy Level ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Spectra ◽  
Electronic Absorption Spectra ◽  
Orbital Energy ◽  
Absorption Bands ◽  
The Relationship ◽  
Orbital Energy Level

Determination of the two Maleinitriledithiolate • phenanthroline-5 ,6-dione Lynn mixed copper (II), zinc (II) complexes MLL' (L=mnty, 1,2 twelve dicyanoethylene-1,2 - thiol ion L '= phen-5, 6-dione, l, 10 - phenanthroline-5 ,6-one o) amine in dimethy-l phthalate (DMF), acetone (Acet.) and chloroform (HCli) electronic absorption spectra corresponding to transitions studied the relationship between the absorption bands in the electronic spectra associated molecular orbital energy level diagram to explore their photographic oxidation characteristics in DMF.

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