Showing papers on "Potassium dichromate published in 1976"
51 citations
TL;DR: Instrumentation for cold-vapor atomic absorption determination of mercury has been improved by several modifications including an a.p.c. switching circuit; a single module for the light source, beam splitter, and reference PMT; and the use of an electrically heated glass tube to vaporize water mist, in place of the conventional magnesium perchlorate drying tube as discussed by the authors.
43 citations
TL;DR: The kidney slice technique has been found to be a sensitive indicator in the assessment of halogenated hydrocarbon-induced nephrotoxicity and differential effects of compounds on in vitro organic acid and base trasport provides information about the transport of these compounds as well as about their neph rotoxicity.
Abstract: A number of studies by the author and other investigators are reviewed in which the in vitro kidney slice technique has been used to evaluate the nephrotoxicity of various compounds. The kidney slice technique can be used to determine the effect of prior drug treatment of laboratory animals on renal organic acid (p-aminohippurate) or organic base (N-methylnicotinamide) transport, on glucose synthesis, and on oxygen consumption by renal coritical slices. The nephrotoxic agents uranyl nitrate and potassium dichromate exert inhibitory effects on renal function, althouhg both agents enhance organic base transport at low doses and potassium dichromate enhances organic acid transport at moderate doses. Enhanced PAH transport has been found to be a sensitive indicator of gentamicin induced nephrotoxicity, while inhibition of other parameters has been reported. The tissue slice method is less effective in evaluation chronic nephrotoxicity such as that produced by lead. The inhibitory effect of mercurial diuretics has been shown to be due to the general depression of metabolic activity by mercury. The kidney slice technique has been found to be a sensitive indicator in the assessment of halogenated hydrocarbon-induced nephrotoxicity. Differential effects of compounds on in vitro organic acid and base trasport provides information about the transport of these compounds as well as about their nephrotoxicity. Although it is often desirable to perform in vivo tests or other in vitro renal function tests, the kidney slice technique has proved to be extremely useful in toxicological evaluations.
42 citations
TL;DR: Golgi's light microscope method of selective silver impregnation for nervous tissue combined with electron microscopy appears to offer a promising method for working out the detailed anatomy of individual neurons and their connections.
Abstract: Golgi's light microscopic method of selective silver impregnation for nervous tissue combined with electron microscopy appears to offer a promising method for working out the detailed anatomy of individual neurons and their connections. Insect nervous tissue is fixed in a mixture of 2% paraformaldehyde and 21/2% glutaraldehyde in Millonig's buffer (pH 7.2) before postfixation for 12 hours in a solution brought to pH 7.2 with KOH containing 2% potassium dichromate, 1% osmium tetroxide and 2% D-glucose. The tissue is then transferred to a solution of 4% potassium dichromate for 1 day; and for 1-2 days to a 0.75% silver nitrate solution. After dehydration and embedding in Araldite, 50μm sections am made. Areas of interest are cut from these sections and re-embedded in silicone molds. Ultrathin sections are then cut and stained with uranyl acetate and lead citrate. The Golgi method described here gives good results at the level of both light and electron microscopy.
25 citations
Journal Article•
TL;DR: Following intravenous or intraperitoneal injections of 3H-l-dopa radioactivity in adrenal medullary chromaffin cells of the mouse has been followed by autoradiographic and radioisotopic assay methods.
Abstract: Following intravenous or intraperitoneal injections of 3H-l-dopa radioactivity in adrenal medullary chromaffin cells of the mouse has been followed by autoradiographic and radioisotopic assay methods. For autoradiographic purposes tissues were fixed in either phosphate buffered glutaraldehyde or in 1-5% potassium dichromate in glutaraldehyde pH 7-2. A high initial radioactivity is demonstrated by both autoradiography and radioisotopic assay. During the first hour dopamine is the predominant labelled amine. Between 1 and 4 hours after the injection noradrenaline is in highest concentration and from 1 to 24 hours labelled adrenaline appears and becomes the predominant labelled amine (about 70%) after 24 hours. Autoradiographs of tissues fixed in glutaraldehyde alone confirm that adrenaline is lost from sections by this technique. When 1-5% potassium dichromate is added to glutaraldehyde then adrenline is fixed in A cells and these show only a slightly decreased grain count as compared to NA cells at 5 days; this slight decrease is probably due to more rapid turnover of amines by A cells.
21 citations
TL;DR: Fruits dipped in thiabendazole before storage remained virtually free of fungal attack even after they had completely ripened, indicating that plantain fruits may be sensitive to chlorine.
Abstract: Mature green plantains (Bini variety) dipped in fungicide and stored with Purafil in polyethylene bags, remained green and hard for 3–4 weeks before ripening started. Fruits stored with Purafil or potassium permanganate kept longer (by 2 weeks) than those stored with potassium iodate or potassium dichromate. Severe chemical and fungal damage occurred in fruits stored with calcium hypochlorite, indicating that plantain fruits may be sensitive to chlorine. No significant difference in storage life was observed between fruits stored in polyethylene bags alone and those stored in potassium iodate or potassium dichromate. There was much lower incidence of fungal infection in fruits dipped in thiabendazole (1 g/l) than those dipped in Diathane M45 (3 g/1). Fruits dipped in thiabendazole before storage remained virtually free of fungal attack even after they had completely ripened.
16 citations
TL;DR: A simplified and improved chemical oxygen demand (COD) procedure for water and waste water samples containing up to 1500 mg Cl l−1 was proposed in this paper, where the detection limit is 3 mg L−1 and the relative standard deviation at the 112 mg COD l− 1 level is 4.3%.
16 citations
14 citations
TL;DR: Out of 30 patients positive to 0.05 % dichromate when the patch lest was done routinely, 29 were also positive when thePatch test was removed after 24 h, and the effect of the earlier removal of the patch test was also noted in seven other patients, when results of tests with lower dichromates were taken into account.
Abstract: The rate of release in vitro of four potassium dichromate concentrations (0.5, 0.1, 0.05 and 0.01%) was determined. In the course of 24 h, 90.1-97.5% was released of the total K2Cr2O7 amount in 48 h. Out of 30 patients positive to 0.05% dichromate when the patch test was done routinely, 29 were also positive when the patch was removed after 24 h. The effect of the earlier removal of the patch test was also noted in seven other patients, when results of tests with lower dichromate concentrations were taken into account.
13 citations
TL;DR: A procedure has been devised for the separate determination of benzoic and sorbic acids in orange juice based on the steam distillation of these preservatives from an acidified juice into an alkaline trap and recovery of both preservatives were satisfactory.
Abstract: A procedure has been devised for the separate determination of benzoic and sorbic acids in orange juice. It is based on the steam distillation of these preservatives from an acidified juice into an alkaline trap. The distillate is divided into two portions, each of which is treated with potassium dichromate and sulphuric acid, but under different conditions. Drastic oxidation leads to the destruction of sorbic acid and, after re-distillation, allows the determination of benzoic acid at 225 nm (with no interference from sorbic acid). Milder oxidation selectively converts sorbic acid into malonaldehyde, and the latter is subsequently converted into a coloured compound and determined at 532 nm (with no interference from benzoic acid).Recoveries of both preservatives from orange juice were satisfactory.
11 citations
ARCO1
TL;DR: An extremely rapid Golgi procedure for immersion impregnation of the whole brain of the frog Rana esculenta is described and the results show neuronal details on a clear background.
Abstract: An extremely rapid Golgi procedure for immersion impregnation of the whole brain of the frog Rana esculenta is described. It uses an isotonic 2% osmium tetroxide solution buffered with sodium barbital at pH 7.2 that has previously been used for electron microscopy. To 15 ml of this solution 85 ml 3% potassium dichromate is added just before us. Twelve-hour treatments (6 hr in the chrome-osmium solution plus 6 hr in 0.75% silver nitrate) are sufficient to obtain consistently excellent impregnations of external brain formations. Twenty-four-hour treatments (12 hr in the chrome-osmium solution and 12 hr in the silver solution) impregnate also the deeper regions of the brain. The results show neuronal details on a clear background.
TL;DR: In this article, the authors described an automated version of the most popular calorimetric (thiobarbituric acid) method, originally proposed by Schmidt, which uses a gas diffusion membrane in lieu of steam distillation for the separation of sorbic acid from the food samples.
Abstract: The increasing use of sorbic acid and sorbates has created a need for a rapid, reliable and accurate analytical procedure for the routine analysis of these materials in food products. In this paper is described an automated version of the most popular calorimetric (thiobarbituric acid) method, originally proposed by Schmidt. The procedure uses a gas diffusion membrane in lieu of steam distillation for the separation of sorbic acid from the food samples. The separated acid is cleaved with potassium dichromate in acidic medium to yield an intermediate malon-aldehyde, which in turn, when reacted with thiobarbituric acid, produces a red dye. The absorbance of the red color, measured at 530 nm was proportional to the concentration of the sorbic acid in the sample. This automated procedure is capable of analyzing 30 samples per hour.
TL;DR: To white paraffin containing potassium dichromate in various concentrations (0.5,0.1, 0.05 and 0.01%) the following emulsifiers were added: 10% glycerol monostearate; 10% Tween 60, and 3% Span 20.
Abstract: To white paraffin containing potassium dichromate in various concentrations (0.5, 0.1, 0.05 and 0.01%) the following emulsifiers were added: 10% glycerol monostearate; 10% Tween 60, and 3% Span 20. Pa
TL;DR: In this article, the determination of reduced substances in sub-hydric soils is possible by rapid oxidation with a diluted potassium dichromate/sulfuric acid solution at room temperature, and subsequent titration with FeSO4 solution.
Abstract: Quantitative determination of reduced substances in subhydric soils
The determination of reduced substances is possible by rapid oxidation with a diluted potassium dichromate/sulfuric acid solution at room temperature, and subsequent titration with FeSO4 solution. These values (meq/100 ml of fresh sample) show a nonlinear, negative correlation with redox potential, and increase with increasing content of organic material. Sulfides, expressed as FeS, amount to appr. 50 % of the reduction equivalents. Subhydric soils rich in nutrients show an increasing amount of reduced substances with increasing depth, whereas oligotrophic and mesotrophic soils give no distinct depth function.
TL;DR: A potentiometric procedure for the assay of mercaptoacetic acid with potassium dichromate in the presence of potassium iodide is described, using starch or naphthol blue-black as indicators.
Abstract: A potentiometric procedure for the assay of mercaptoacetic acid with potassium dichromate in the presence of potassium iodide is described. The oxidation of mercaptoacetic acid proceeds via the liberation of iodine from potassium iodide (added to the titration mixture) by the addition of potassium dichromate. Oxalic acid is used as the catalyst to accelerate the reaction between potassium iodide and potassium dichromate. Mercaptoacetic acid is also determined visually with potassium dichromate, using starch or naphthol blue-black as indicators.
TL;DR: In a proposed new procedure the sample is treated with bromine, the excess of bromines removed, and the residue extracted with methanol and the filtrate is evaporated to remove methanl and the bromides are dissolved in hydrochloric acid for determination of metallic iron.
TL;DR: In this paper, it was shown that the drag of Xmax is shifted from that obtained in the binary system, when mixed complex formation occurs with the AL, to the presence of lower complexes.
Abstract: eluded that dragged Xmax is shifted from that obtained in the binary system, when mixed complex formation occurs with the AL. Since Succ is able to hold Ti in solution at PH 4·0 and still the Xmax is at a higher value, the drag of Xmax cannot be attributed to hydrolysis and polymerization of free metal iO:1. As mentioned earlier, this is attributed to the simultaneous presence of lower complexes-,