Ewa Kleszczewska

Application of reinecke salt and alizarin S for the determination of promazine.

Reinecke salt and alizarin S have been tested as reagents for the determination of promazine. They react in neutral and acidic media with promazine forming a reddish and brown crystalline compounds. The compounds are sparingly soluble in water but fairly soluble in acetone and methanol. The quantitative extraction of compound of promazine with alizarin S has been used for the extractive spectrophotometric determination of promazine. Formation of promazine ion-association complex with Reinecke salt has been applied for indirect determination of low concentrations of promazine by AAS measurement of the chromium content of the reineckate counter - anion.

Spectrophotometric determination of imipramine hydrochloride using ammonium peroxidisulfate and niobium(V) thiocyanate complex

Two methods for the determination of imipramine hydrochloride are presented. One method is based on the oxidation of imipramine using ammonium peroxidisulfate with the formation of colored products. This property is the basis of a new spectrophotometric method for imipramine determination. The second method employs the liability of the imipramine tertiary amine group nitrogen atom to form ion-pair compound with niobium(V) thiocyanate complex. The formed ion associate is insoluble in water but well-soluble in organic solvents. Both reactions were followed spectrophotometrically by measuring the absorbances at 658 nm (oxidative method) and at 350 nm (extractive method). The methods have been successfully applied to the determination of imipramine in pharmaceutical preparations. The results were compared with those obtained by the official procedure.

Voltammetric investigation of reaction of L-ascorbic acid with chlorpromazine hydrochloride and potassium iodide

Abstract Electrochemical oxidation of l-ascorbic acid by a chlorpromazine and a potassium iodide at a platinum electrode in 5 × 10−1 M K2SO4 + 5 × 10−1 M KHSO4 has been studied. l-Ascorbic acid was the oxidation product, which has been verified by spectrophotometry and potentiometry. The rate constant for the catalytic reaction was evaluated as (6.4 ± 0.05) × 103 M−1 s−1 for a chlorpromazine and as (7.4 ± 0.04) × 103 M−1 s−1 for a potassium iodide. Experimental conditions, which maximize the current efficiency of this electrochemical oxidation, such as pH value and the concentration of the catalyst, were also investigated and discussed in this article.

FIA-Spectrophotometric Determination of Ascorbic Acid in Rat's Lung by Reduction of Iron(III)

Abstract A FIA indirect spectrophotometric determination of ascorbic acid (vitamin C) was developed using its reducing action on Fe(III) and following the spectrophotometric determination of the reduced ion by 2,2′-dipyridyl and monitoring the absorbance signal at 520 nm. The procedure is based on the reduction of iron(III) to iron(II) with ascorbic acid. The iron(II) obtained is then able to react with 2,2′-dipyridyl in order to form a colored complex. The linear range of the method was 1.0–10.0 ppm ascorbic acid. The proposed method was sensitive, rapid (40 samples/h) and reproducible (relative standard deviation 1.2%, n = 40). Satisfactory results were obtained in the determination of ascorbic acid in rats lung.

Cu(II) complexation does not affect oxytocin action on pregnant human myometrium in vitro

OBJECTIVE Copper may influence the in vivo and in vitro uterine activity. Recent evidence shows that cupric ions can easily form complexes with oligopeptides like oxytocin (OXT). The high complex stability in vitro suggests a possibility of complex formation in vivo. STUDY DESIGN In vitro isometric contractions were recorded in uterine tissues from pregnant women undergoing caesarean sections and the effect of OXT and the Cu-OXT complex on isolated human pregnant myometrium was investigated. RESULTS In the concentration range from 10(-14) to 10(-6)M of OXT alone, pre-formed Cu-OXT complex, and OXT following sample preincubation with Cu(II) salt, nosignificant differences were observed for the following parameters of pregnant uterine smooth muscle contraction: the area under the curve, frequency and amplitude of contraction. CONCLUSION The binding of Cu(2+) ions does not abolish the ability of OXT to interact with oxytocin receptors and stimulate myometrial contraction in vitro.

Levels of l-ascorbic acid and cadmium in the saphenous vein of patients with coronary artery disease are negatively correlated

BACKGROUND The aim of this study was the simultaneous determination of levels of cadmium and l-ascorbic Acid (AA) in human saphenous vein (SV) used in coronary artery bypass grafting (CABG) and check whether there is a relationship between these levels. METHODS Human SV were collected from 40 patients (20 men and 20 women; age, 40-75 years) at the time of routine coronary artery surgical revascularization. The concentration of cadmium in the tissue was determined according to the GF AAS-atomic absorption method. The concentration of AA was assayed in supernatant by FIA method with spectrophotometric detection. RESULTS AA concentration (mean±SD); men: 98,7±13,18μg/g tissue, women: 96,06±11,98μg/g tissue. Cadmium concentration(mean±SD); men: 309±103,71ng/g tissue, women: 348,5±255,71ng/g tissue. Correlations among concentrations of AA and cadmium were insignificant negative in the group of men (Pearson r=-0,1504, p=0,5269) and in the group women (Pearson r=-0339, p=0144). CONCLUSIONS Negative correlations among concentrations of AA and cadmium in human SV obtained in our study may indicate a protective effect of this vitamin in relation to toxic cadmium.