N.M.Made Gowda

Mutagenic sterol hydroperoxides

Sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide show weak dose-response direct mutagenicity towards Salmonella typhimurium strain TA 1537 in a liquid medium incubation bioassay. Responses were compromised by metabolism of the sterol hydroperoxides and by phase separation during the incubation period. Mutagenicity responses were increased by added superoxide dismutase but diminished by added rat liver S9 enzymes and abolished by added catalase. Catalase also abolished the stimulatory effect of superoxide dismutase. These results indicate that superoxide and peroxide be implicated in the mutagenicity responses.

Sterol hydroperoxide metabolism by Salmonella typhimurium

In order to rationalize multiphasic dose-response data evincing mutagenicity towards Salmonella typhimurium TA1537 for sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide their metabolism by the bacterial test strain was investigated. The 5 alpha-hydroperoxide was isomerized to the 7 alpha-hydroperoxide and reduced to 5 alpha-cholest-6-ene-3 beta,5-diol; the 7 alpha-hydroperoxide was reduced to cholest-5-ene-3 beta,7 alpha-diol and transformed to 3 beta-hydroxycholest-5-en-7-one. The 3 beta,5 alpha-diol and 3 beta,7 alpha-diol were not interconverted nor was either transformed to the 7-ketone.

Application of Azure C for the extractive spectrophotometric determination of microgram amounts of penicillin

A simple, accurate, and rapid method for the quantitative determination of penicillin is proposed. The method is based on the formation of a blue penicillin-Azure-C ion-pair that can be extracted into chloroform in phosphate-citric acid buffer. The molar absorptivities for sodium penicillin G and potassium penicillin V at 635 nm were 5.46 X 10(3) and 2.19 X 10(4) l/mol/cm, respectively. Beers law was valid over the concentration range of 4-80 micrograms/ml for sodium penicillin G and 3-55 micrograms/ml for potassium penicillin v. Maximum absorbance was obtained almost instantaneously and was stable for several days. The method was successfully applied to pharmaceutical preparations.

On reaction of sterol hydroperoxides with superoxide

Reduction of sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and cholesterol 7 alpha-hydroperoxide by KO2 (or other strong base in air) solubilized by crown ether in dimethylsulfoxide gave only corresponding alcohols, but in the presence of cholesterol (or other sterols) gave 3 beta-hydroxycholest-5-en-7-one together with the corresponding alcohols. Both hydroperoxides likewise gave the corresponding alcohol and ketone products with KO2 in benzene and in oxidations by ceric ammonium nitrate in a biphasic system. The 7-ketone product is recognized as deriving from termination reactions of sterol peroxyl and/or oxyl radicals.

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.

Assay of d-cycloserine by chloramine-B, bromamine-T, and bromamine-B

Abstract The reaction between d -cycloserine (DCS) and aromatic N -haloamines proceeds quantitatively over a wide range of experimental conditions. Simple titrimetric procedures for the assay of DCS are described. Oxidation of DCS involves an eight-electron change and the oxidation products are identified. The methods can be used for the assay of the antibiotic in medicinal preparations as well as for calculating the number of ligand molecules present in metal complexes of DCS.

Ethylisobutrazine hydrochloride as a selective and sensitive reagent for the spectrophotometric determination of vanadium(V) and its application to vanadium-bearing minerals and alloys

Abstract Ethylisobutrazine hydrochloride is proposed as a selective and sensitive reagent for the spectrophotometric determination of vanadium(V). It forms a red-colored species with vanadium(V) in 3.5–6.5 M phosphoric acid medium. An eight-fold molar excess of reagent is necessary for the full development of the color. The red species exhibits an absorption maximum at 518 nm with a molar absorptivity of 9.75 × 10 3 liters mol −1 cm −1 . Sandells sensitivity is 5.2 ng cm −2 . Beers law is obeyed over the range 0.1–6.2 ppm of vanadium(V) with an optimum concentration range of 0.4–6.0 ppm. The effects of acidity, time, temperature, order of addition of reagents, reagent concentration, and the interferences from various ions, are reported. The method has been used successfully for the determination of vanadium in ilmenite and vanadium steels that contain chromium, molybdenum, manganese, nickel, copper, tungsten, and titanium.

Spectrophotometric determination of microgram amounts of platinum

2-Ethyl-10-[3-(dimethylamino-2-methyl)propyl]phenothiazine hydrochloride (ethylisobutrazine hydrochloride) forms an orange-red complex with platinum(IV) at room temperature (26 ± 2 °C) in hydrochloric acid-sodium acetate buffer medium containing copper(II) ions. The complexation is complete within 10 min. The complex exhibits an absorption maximum at 529 nm with a molar absorptivity of 1.90 × 104 liters mol−1 cm−1. Beers law is obeyed over the concentration range 0.4–7.8 ppm of platinum. A 50-fold molar excess of the chromogenic reagent is necessary for the development of maximum color intensity. Jobs method of continuous variation, the molar-ratio method, and the slope-ratio method indicate a 1:1 composition for the complex. The effects of pH, time, temperature, reagent concentration, order of addition of reagents, and interference of various ions are reported. The reagent has also been used successfully for the determination of platinum in minerals and alloys.