Potassium dichromate

About: Potassium dichromate is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 18967 citations. The topic is also known as: Potassium dichromate(VI) & Chromium potassium oxide.

Determination of ethanol in wine by titrimetric and spectrophotometric dichromate methods: collaborative study.

Abstract: A dichromate-spectrophotometric method for the determination of ethanol in wine was compared in a collaborative, matched pair study with the AOAC dichromate-titrimetric method, 11.008-11.011. Both methods require distillation of the sample into dichromate. The titrimetric method measures ethanol by titrating the excess dichromate with ferrous ammonium sulfate after conversion of ethanol to acetic acid; the spectrophotometric method directly measures the reduced dichromate formed after oxidation. In addition to comparing the 2 methods, the collaborative study also compared the use of 2 types of assemblies for obtaining the ethanol distillate: the Scott-type, which is used in 11.008-11.011, and the electric Kirk-type. Results of the collaborative study indicated that the repeatability and reproducibility of the official titrimetric method were generally far superior to those of the spectrophotometric method; therefore, adoption of the spectrophotometric method is not recommended. Comparison of titrimetric method results obtained using the 2 types of stills indicated that repeatability and reproducibility were somewhat better when Scott apparatus was used, but measurements using Kirk-type compared well in the range of ethanol concentrations found in table and fortified wines. The Kirk-type distillation apparatus has been adopted official first action as an alternative to Scott apparatus in the dichromate oxidation method for ethanol in wine, 11.008-11.011.

On the hardening of the chorion of the fish egg after fertilization. iii. the mechanism of chorion hardening in oryzias latipes

Abstract: 1. Oxidizing agents, such as potassium ferricyanide, sodium tetrathionate, iodine, hydrogen peroxide, sodium periodate, chromic acid and potassium dichromate, cause hardening of the chorion. Chromic acid is less effective than any of the other agents.2. In the presence of reducing agents, such as sodium sulfide, potassium cyanide, sodium thiosulfate, sodium sulfate, sodium thioglycolate, ammonium sulfate, and potassium ferrocyanide, the chorions fail to harden.3. Treatment of unfertilized eggs with mercuric chloride or p-chloromercuribenzoate induces the inhibition of chorion hardening when they are subsequently inseminated in Ringer's solution. The same result is also obtained in the cases where both agents are applied after fertilization. Either inhibitory effect is removed if the treatment is followed by that with potassium cyanide.4. Iodoacetic acid and chloroacetophenone likewise inhibit hardening when eggs are treated after insemination.5. Neither urea nor lithium bromide has any effect on the chori...

Genotoxicity of chromium in human gastric mucosa cells and peripheral blood lymphocytes evaluated by the single cell gel electrophoresis (comet assay).

Abstract: Hexavalent chromium compounds are well-recognized carcinogens. They easily penetrate the cell membrane and are reduced inside the cell to their trivalent form, which is supposed to react directly with DNA. Chromium is present in some workplaces as well as in water resources and food chain, so it can interact with the mucosa of the gastrointestinal tract. In order to elucidate the genotoxic potency of chromium in human gastric mucosa (GM) cells, the DNA-damaging effect of potassium dichromate (K2Cr2O7) was investigated using alkaline single cell gel electrophoresis (comet assay). Biopsy samples were obtained during gastroscopy from macroscopically healthy tissue of the stomach. Parallel test with human peripheral blood lymphocytes was also performed. Both types of cells were incubated at 37 degrees C with 1.6 mM of K2Cr2O7 for 1 h and after washing, were placed in a chromium-free medium to examine DNA repair. Alkaline single cell gel electrophoresis (comet assay) was used to assess DNA damage and repair. Chromium introduced a damage to DNA both in the GM cells and lymphocytes. The effect induced by K2Cr2O7 in GM cells was comparable with that caused in the lymphocytes. Treated cells were able to recover within a 60-min incubation in a chromium-free medium at 37 degrees C. The results obtained indicate that hexavalent chromium compounds, which may be found in the diet, can interact directly with DNA of the mucosa of the stomach.