Showing papers on "Potassium dichromate published in 1980"

Follow-up study of patients with contact dermatitis caused by chromates, nickel, and cobalt.

Abstract: The patch test results from 1,000 patients tested with the ICDRG standard series are analyzed for positive reactions to potassium dichromate, nickel sulphate, and cobalt chloride Nickel appears to be

Relationship between the induction of micronuclei in marrow cells by chromium salts and their carcinogenic properties

Abstract: The micronucleus test has been used to study the mutagenic activity of chromium derivatives and to examine the relationship between their carcinogenic properties and their ability to induce chromosomal damage. It has been found that potassium dichromate is a potent mutagen increasing, for instance, the rate of micro-nucleated erythrocytes while calcium chromate and chromic nitrate are ineffective. From our observations and the data on carcinogenicity, it can be concluded that the micronucleus test cannot be used to predict the carcinogenic properties of chromium derivatives.

Redox substoichiometry in isotope dilution analysis

Abstract: Radiometric titration of antimony(III) with potassium bromate in hydrochloric acid media using the standard series method provided much valuable informations on the titration errors which depended on the concentrations of the acid and antimony(III). The hydrochloric acid concentrations between 2.5 and 3.0M were found to be optimum for the oxidation of antimony(III) amounts of 4 μg or less. Under these optimum reaction conditions the redox substoichiometric isotope dilution analysis was applied to the determination of antimony in metallic zinc and the satisfactory results were obtained, without the separation of matrix element. Also, the merits of various oxidizing agents hitherto studied for the quantitative oxidation of antimony(III) were compared and discussed.

Variations of DNA Physico-Chemical Parameters in its Interactions with Mutagenic and/or Carcinogenic Compounds

Abstract: Mugagens and/or carcinogens (genotoxics) mainly act by altering DNA structure binding themselves to the nitrogen bases or to phosphate residues, causing a break in the nucleic acid chain or inserting themselves between the bases.

Method for the manufacture of capacitive electronic discs

Abstract: A method for passivating the surface of a recorded metal substrate in which the substrate is immersed for 5-30 minutes in a 35° C.-85° C. aqueous bath containing from about 5 to 30 g/l of an alkaline cleaner and from about 2.5 to 20 g/l of sodium dichromate, potassium dichromate, sodium permanganate, potassium permanganate, or mixtures thereof.

Chemical treatment method for zinc and zinc alloy

Abstract: PURPOSE:To reduce the amt of hexavalent chromium used and to facilitate waste liquor treatment, etc by treating zinc and a zinc alloy with a treating bath consisting of sodium molybdate, potassium dichromate, phosphoric acid and acetic acid CONSTITUTION:Zinc and a zinc alloy are subjected to chemical treatment with a treating bath of the following compsn: Sodium molybdate 15-50 g/l, potassium dichromate 01-05 g/l, phosphoric acid 0-25 cc/l and acetic acid 0-20 cc/l In case of dipping treatment a bath temp of 50-80 degC, a dipping time of 1-45 min and a bath pH value of 25-5 are suitable

Constant current coulometric method for the determination of uranium in active process solutions

Abstract: The determination of uranium in the range of 2.5–5 mg by constant current coulometry is described. The procedure is based on the modified version of the DAVIES—GRAY method, wherein uranium, after the reduction step, is oxidized by adding a known amount of potassium dichromate, and the excess of dichromate is determined by titration with Fe2+ solution. Fe2+ ions needed for the titration are generated in situ with 100% current efficiency by electrolytic reduction of Fe3+. The method is found to be accurate with a coefficient of variation better than 0.2%.

Calibration checking standard solution for residual chlorine gauge

Abstract: PURPOSE:To facilitate and easy modification as well as to realize a long-time reservation for the calibration checking standard solution of the iodine substitution type polarograph-system chlorine gauge which measures the residual chlorine in the water process system, by using the oxidizing agent which oxidizes the iodine ion and the acid which gives a fixed pH in combination. CONSTITUTION:The calibration checking standard solution for the iodine substitution type polarograph-system residual chlorine gauge is produced by mixing the oxidizing agent which liberates the iodine through oxidization of the iodine ion and the acid (such as the sulfuric acid, nitric acid, etc.) of such amount as to secure pH1.5-3.0 when mixed with the active reagent at introduction into the residual chlorine gauge. The oxidizing agent uses the sodium iodate, potassium iodate, potassium dichromate and the like, and is modified previously up to the 1-1000- fold density compared with the introduction time into the residual chlorine gauge. And in the case of the bromine substitution type polarograph-system liberation chlorine gauge, the potassium salt of bromic acid or the sodium salt is used for the oxidizing agent.

Contaminación aguda por vertidos textiles: Tratamiento de carpines dorados (Carassius auratus) con dicromato potásico; determinación de la toxicidad y niveles de cromo en branquias.

Abstract: Chromium is quantitatively the most import metal in the rejects of the Textile Industry; it comes essentially from dyeing processes with chromatable dyes. Carps of the species Carassius auratus have' been submitted to the acute treatment with potassium dichromate dissolved in the water of experimental tanks. Toxicity and chromium levels in branchia are determined. The chromium concentration in the branchial tisswes is obtained by means of atomic absortion spectrophotometry, previous digestion with NO3H and C1H (1:3). Curves % Mortality-Time of treatment for doses of hexavalent chromium are established.

Simple methods for oxidation of o-allylphenols to chrom-3-enes

Abstract: The reaction of o-allylphenols (1) with potassium dichromate dissolved in benzene using Adogen 464, a commerical mixture of methyl-trialkyl-(C8–C10)-ammonium chloride, or with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in ether affords the corresponding chrom-3-enes (3) in good yields.