H.Sanke Gowda

Chlorpromazine hydrochloride as a new redox indicator in vanadametry.

Chlorpromazine hydrochloride is proposed as an indicator in the vanadametric titration of iron(II) and molybdenum(V). It gives a sharp, reversible colour change from green to violet at the equivalence point. It has advantages over the diphenylamine class of indicators. Its redox and transition potentials are reported.

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

Abstract 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.

Spectrophotometric studies on platinum-promethazine hydrochloride complex.

Abstract Promethazine hydrochloride forms a yellowish-green complex with platinum(IV) in sodium acetate-hydrochloric acid buffer containing copper catalyst. The complex has an absorption maximum at 406 nm with molar absorptivity 1.001 × 104 liters mol−1 cm−1. The sensitivity of the reaction is 19.5 ng/cm2 for log I ° I = 0.001 . Beers law is valid over the range 0.5–7.5 ppm of platinum(IV) with optimum concentration range 0.8-7.3 ppm. Continuous variations, mole ratio, and slope ratio methods indicate 1:1 composition for the complex. The effects of pH, time, temperature, order of addition of reagents, reagent concentration, and interferences from various ions are reported.

Magnetic, spectral and thermal studies of copper(II) phenothiazine complexes

Abstract Complexes of copper(II) with eight phenothiazines have been prepared. Probable structures for the complexes have been proposed on the basis of elemental analysis and conductometric, spectral, thermogravimetric and magnetic susceptibility data.

N-Substituted phenothiazines as redox indicators in bromatometry

Diethazine hydrochloride, butaperazine dimaleate, trifluoperazine hydrochloride, promethazine hydrochloride, prochlorperazine maleate and chlorpromazine hydrochloride have been studied as indicators in bromate titration of quinol, metol and ascorbic acid. They give a very sharp reversible colour change at the equivalence point. Their formal potentials have been determined. A simple but accurate method for the estimation of quinol and metol is reported.

Rapid spectrophotometric determination of phenothiazines with molybdophosphoric acid

Abstract A simple and rapid spectrophotometric method for the determination of six phenothiazines can be based on the formation of a coloured compound between molybdophosphoric acid and phenothiazines. The i.r. and e.s.r. spectra of the coloured compounds showed that molybdophosphoric acid oxidizes phenothiazines to a radical cation with which it then forms a coloured compound. The proposed method is employed for the determination of phenothiazines in pharmaceutical preparations. Calibration graphs are linear over ranges of about 100–2000 μg of the phenothiazine.

N-substituted phenothiazines as indicators in titrations with chloramine-T

Abstract Trifluoperazine dihydrochloride, butaperazine dimaleate, promethazine hydrochloride, diethazine hydrochloride, prochlorperazine maleate and chlorpromazine hydrochloride have been studied as redox indicators in titrations of hydroquinone, metol and ascorbic acid with chloramine-T. The end-points obtained are sharper than with conventional indicators. The molar absorptivities of the oxidized indicators are reported. Simple but accurate methods for the determination of hydroquinone and metol are described.

Prochlorperazine bismethanesulfonate: Sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium

Abstract Prochlorperazine bismethanesulfonate (PCPMS) is proposed as a new sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium. PCPMS forms a red-colored species with osmium(VIII) or osmium(VI) instantaneously at room temperature in 5 M phosphoric acid medium. The red species exhibits maximum absorbance at 529 nm. Beers law is valid over the concentration range 0.05–3.6 ppm for osmium(VIII) and 0.15–6.4 ppm for osmium(VI). Sandells sensitivity of the reaction is 2.89 nm cm−2 for osmium(VIII) and 4.24 ng cm−2 for osmium(VI). The effects of time, temperature, acidity, order of addition of reagents, reagent concentration, and diverse ions are investigated. The application of the proposed method in the determination of osmium content in synthetic ores has been explored.

Propericiazine as a reagent for the spectrophotometric determination of ruthenium(III)

Abstract Propericiazine forms an orange-red species with ruthenium(III) immediately in 6–8 M phosphoric or hydrochloric acid or 4.5–5.5 M sulphuric acid. The absorption maximum is at 511 nm and the molar absorptivity is 1.1 × 10 4 1 mol −1 cm −1 . Beers Law is obeyed over the range 0.2–9.4 mg 1 −1 (optimum range 0.5–9.0 mg 1 −1 ). Interferences are described. The method is used to determine ruthenium in synthetic zinc–magnesium alloy and uranium alloy (fuel) solutions.

Rapid spectrophotometric determination of cerium(IV), arsenic(III), and nitrite with perphenazine

Abstract Perphenazine dihydrochloride, PPN, is proposed as a new reagent for the spectrophotometric determination of cerium(IV), arsenic(III), and nitrite. The reagent forms a red-colored species with cerium(IV) instantaneously in 3.5–5.5 M phosphoric acid medium. The red species exhibits maximum absorbance at 516 nm. A 15-fold molar excess of PPN is necessary for the full development of the color intensity. Beers law is obeyed over the cerium concentration range 0.4–20 ppm and Sandells sensitivity is found to be 0.016 μg/ cm2. The effects of acidity, time, order of addition of reagents, temperature, reagent concentration, and diverse ions are reported. The proposed method offers the advantages of good sensitivity, simplicity, rapidity, selectivity, and a wider range of determination without the need for heating or extraction. Arsenic(III) and nitrite are also indirectly determined. The method is extended to the determination of cerium content in synthetic mixture corresponding to misch metal.