Rapid spectrophotometric determination of ruthenium with diethazine hydrochloride

Diethazine hydrochloride reacts with ruthenium(III) instantaneously at high acidity (sulphuric or hydrochloric acid) to form a red 1:1 complex with absorbance maximum at 515nm. A tenfold molar excess of reagent is necessary for complete complexation. Beer's law is obeyed for 1.0-10.4 ppm of ruthenium(III), with optimum concentration range 2-9 ppm. The molar absorptivity is 5.35 x 10(3) 1.mol(-1) .cm(-1).     

Spectrophotometric determinations of some phenothiazine drugs

A rapid and sensitive spectrophotometric method has been developed for the quantitative determination of some phenothiazine derivatives as the pure substances and in different dosage forms. The method is based on the formation of red coloured products with 1% iodic acid in sulphuric or phosphoric acid medium. The reaction involves oxidation of the phenothiazine nucleus into a semiquinonoid radical. The optimum reaction conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with phenothiazine drugs has been studied. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.     

Tungstophosphoric acid as a new reagent for the spectrophotometric determination of phenothiazines

A simple and rapid spectrophotometric method for the determination of phenothiazines based on the formation of a colored compound between tungstophosphoric acid and phenothiazines is described. The proposed method is successfully employed for the determination of phenothiazine drugs in various pharmaceutical products.     

Attenuation of second sound in superfluid 3He-A1

The attenuation of second sound (spin-entropy) wave in the superfluid A1 phase has been measured in magnetic fields up to 11 T and to sufficiently high frequency to observe the bulk attenuation proportional to the square of frequency. The measured attenuation coefficient is compared with the existing theories of hydrodynamics and dissipative coefficients. The resulting "excess" attenuation is discussed in terms of the temperature dependent spin diffusion coefficient in the superfluid.