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Cathodic adsorptive stripping square-wave voltammetric determination of nifedipine drug in bulk, pharmaceutical formulation and human serum

“…Several analytical methods have been described for the assay of nifedipine in pharmaceutical formulations and biological fluids. These methods include spectrophotometry [3,4,5,6], gas chromatography [5,6,7,8,9,10,11,12,13,14], liquid chromatography [6,15,16], high-performance thin-layer chromatography [17], high-performance liquid chromatography [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41], flow-injection tandem mass spectrometry [42] polarography [43,44], linear-sweep voltammetry [45] and differential-pulse stripping voltammetry [46,47].…”

Association of Complex Ferrumcyanide Anions with Pinacyanol Cation in Aqueous Solution

“…The preparation technique of dye solutions as well as other reagents was presented in the prior publications [9,11,14]. Throughout the course of the study of Аn iinteraction with the dye the acidity of the solution was kept at the level that ensured coexistence of the corresponding ionic forms.…”

“…A number of "standard" dyes as well as colourless organic ions are used for more detailed investigation of cationic-anionic association in water. They include quinaldine blue and its structural analogues [7,8], quinaldine red [8], astraphloxin [9,10] (as cyanines), tetrabromophenylfluoron [11] (as oxyxanthene dye), rhodamin 110 [12] (as aminoxanthene dye), phenol red [13][14][15] (as sulfonephthalein dye), tetraphenylborat anion (TPB -), tetraphenylarsonium ion (TFA + ) [10,12,15,16], and tetrabutylammonium ion (as colourless ions). Accumulation of experimental data on equilibrium properties of associates not only promotes development of the theory of intermolecular interactions but also allows predicting the thermodynamic and spectral properties of complex species which are formed in solutions [17].…”

Group conjugations of Dirac operators as an invariant of the Riemannian manifold

“…Identity (1) permits us to write the operator L in the form L = γ k P k , where γ k is a solution of system (5). Equivalence (3) means that between matrices γ k and γ k the following connection S γ k = γ k S is true. Let us make a non-singular change of coordinates x i = x i (x i ).…”

“…From the mathematical point of view, operator L is the same Dirac operator D, but in some other representation. In this paper, we consider that sometimes L = D. This is possible if S is a unit matrix in formula (3). The physical consequences of identities ( 1) and (3) were discussed with concrete examples in our papers [1,2].…”