Showing papers on "Potassium dichromate published in 2004"
TL;DR: Results indicate that vitamin C could be used in effective remediation of Cr(VI)-contaminated soils and groundwater in a wide range of pH, with or without sunlight.
174 citations
TL;DR: Results showed a clear DNA alteration in plants as a response to chromium exposure and the effect was dose-dependent, suggesting random DNA mutation in response to potassium dichromate and arguing against preferential sites for mutation.
116 citations
TL;DR: No differences were observed between the reactions before and after placement of the orthodontic appliances; this indicates that they did not sensitize the patients or affect their tolerance to these metals during the study period.
68 citations
TL;DR: In this article, the results indicated that the presence of dichromate has a large influence on the extraction of metals, such as Cu, Co, Zn, and Fe.
64 citations
TL;DR: Taurine seems to exert some beneficial effects against Cr(VI)-induced oxidative stress and chromium accumulation in mice kidney tissue in this study.
Abstract: The kidney has been regarded as a critical organ of toxicity induced by acute exposure to hexavalent chromium [Cr(VI)] compounds. Reactive intermediates and free radicals generated during reduction process might be responsible for Cr(VI) toxicity. In this study, the effects of pretreatment or posttreatment of taurine on Cr(VI)-induced oxidative stress and chromium accumulation in kidney tissue of Swiss albino mice were investigated. Single intraperitoneal (ip) potassium dichromate treatment (20 mgCr/kg), as Cr(VI) compound, significantly elevated the level of lipid peroxidation as compared with the control group (p<0.05). This was accompanied by significant decreases in nonprotein sulfhydryls (NPSH) level, superoxide dismutase (SOD), and catalase (CAT) enzyme activities as well as a significant chromium accumulation (p<0.05). Taurine administration (1 g/kg, ip) before or after Cr(VI) exposure resulted in reduction of lipid peroxidation levels and improvement in SOD enzyme activity (p<0.05). On the other hand, administration of the antioxidant before Cr(VI) exposure restored the NPSH level and CAT enzyme activity and also reduced tissue chromium levels (p<0.05), whereas posttreatment had only slight effects on these parameters. In view of the results, taurine seems to exert some beneficial effects against Cr(VI)-induced oxidative stress and chromium accumulation in mice kidney tissue.
35 citations
TL;DR: In this paper, the results of electron paramagnetic resonance measurements of wet and dry-leached and unleached samples were performed in order to determine the paramagnetic complexes that were formed.
Abstract: Wood treated with CCB (chromated copper borate) has an expected service life of 20–50 years, depending on conditions of service and method of treatment. After this period, treated wood is discarded as special waste. Due to toxic elements (Cu, Cr, and B) in such treated wood, burning and landfill disposal are not considered as environmentally sound solutions. Chemical extraction seems more promising. The principle of the method is to convert fixed biocides in wood into soluble form and leach them out of the wood. In order to elucidate this process, copper(II) sulfate, potassium dichromate, and CCB-treated samples were leached using five different agents, namely, water, an aqueous solution of oxalic or acetic acid, and an aqueous solution of oxalic or acetic acid with ammonia. Afterwards, the amounts of leached copper and chromium were determined. In a parallel experiment, electron paramagnetic resonance measurements of wet- and dry-leached and unleached samples were performed in order to determine the paramagnetic complexes that were formed. The highest chromium leaching was achieved with the aqueous solution of oxalic acid, as chromium was converted into water-soluble chromium oxalate. While the mixture of oxalic acid and ammonia resulted in the highest copper leaching, EPR observation revealed that in this case water-soluble complexes of copper, oxalic acid, and ammonia were formed. We found out that oxalates formation is not the only mechanism responsible for copper or chromium leaching. High acidity may play an important role too.
32 citations
TL;DR: A novel method of photochemical polymerization of thiophene derivatives in aqueous solution catalyzed by potassium dichromate and initiated by illumination is described.
27 citations
TL;DR: Results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemical exposure, and this biochemical parameter could be developed as a biomarker in environmental monitoring.
Abstract: In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobinsshowed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemicalexposure, and this biochemical parameter could be developed as a biomarkerin environmental monitoring.
21 citations
TL;DR: Data on the dermal irritation by copper and its compounds is scant, and its irritancy has not been determined, e.g., in terms of an irritant dose ID50.
Abstract: Data on the dermal irritation by copper and its compounds is scant, and its irritancy has not been determined, e.g., in terms of an irritant dose ID50. Irritancy of copper can only be comparatively characterized in relation to other metal salts. A rank order for the irritancy of metal compounds can be inferred from the patch test concentrations recommended as non-irritating for the purpose of cutaneous allergy testing: potassium dichromate 0.5% in petrolatum; copper sulfate, cobalt chloride and palladium chloride ex equo: 1% in aqueous solution, and nickel sulfate: 5% in petrolatum.
15 citations
TL;DR: In this article, specific morphologies occasionally appear in the crystal growth in gels, such as Potassium dichromate (K 2 Cr 2 O 7 ) and K 2 Cr O 7.
Abstract: Specific morphologies occasionally appear in the crystal growth in gels. Potassium dichromate (K 2 Cr 2 O 7 ) crystals grown in gelatin gel have been found to exhibit various morphologies by varyin...
15 citations
Journal Article•
TL;DR: In this article, a sensitive method was presented for the spectrophotometric determination of phenothiazine derivatives of biological importance, namely, chlorpromazine hydrochloride (CPH), trifluoperazine hydro chloride (TFPH), prochlorperazine maleate (PCPM), and fluphenazine hydric acidification (FPH).
Abstract: A sensitive method is presented for the spectrophotometric determination of phenothiazine derivatives of biological importance. The drugs namely, chlorpromazine hydrochloride (CPH), promethazine hydrochloride (PH), trifluoperazine hydrochloride (TFPH), prochlorperazine maleate (PCPM) and fluphenazine hydrochloride (FPH) are reacted with a fixed amount of dichromate in acidic conditions. After the reaction is complete, the unreacted dichromate is determined by treating with iron(II) and ortho-phenanthroline at a raised pH and measuring the absorbance at 510 nm. The amount of dichromate reacted corresponds to the drug content. The linearity ranges are found to be 5-30, 2.5-25, 5-45, 7.5-60 and 5-50 μg mL -1 for CPH, PH, TFPH, PCPM and FPH, respectively. The apparent molar absorptivity values are in the range 3.46×10 3 -6.47×10 3 L mol -1 cm -1 and the limits of determination range from 0.49 to 1.87 μg mL -1 and the relative standard deviation is less than 2%. The proposed method has been applied for the determination of these drugs in pure form and in pharmaceutical formulations with recoveries in the range 96.28-103.24%. The method was further validated by parallel determination by the official British Pharmacopoeial procedure and by recovery studies.
Patent•
17 Nov 2004
TL;DR: In this article, a vacuum superconduction liquid preparation method was proposed, wherein the composition for preparation comprises potassium dichromate, calcium chloride, ethanol, sodium perborate, boric acid, manganese dioxide, aluminum hydroxide, cobalt oxide, and potassium chloride.
Abstract: A vacuum superconduction liquid preparation method, wherein the composition for preparation comprises potassium dichromate, calcium chloride, ethanol, sodium perborate, boric acid, manganese dioxide, aluminum hydroxide, cobalt oxide, sodium peroxide, and potassium chloride. The preparation process comprises heating, agitating, and dissolution. The invention realizes high heating efficiency.
TL;DR: This study suggests that potassium dichromate is a suitable alternative to freezing for preservation of whole blood for dioxin, dibenzofuran, and PCB measurements when either lipid or wet weight based results are reported.
TL;DR: Transport inhibition observed in larvae exposed to potassium dichromate was accompanied by changes in ascorbate peroxidase and dehydroascorbate reductase activities, whereas those exposed to fenitrothion displayed an increase in transaminase activity.
Abstract: The effect of sublethal concentrations of potassium dichromate and fenitrothion on sodium-leucine cotransport in brush border membrane vesicles from Chironomus riparius larvae has been investigated. Exposure to potassium dichromate and fenitrothion caused a dose- and time-dependent inhibition of leucine uptake. Transport inhibition is easily detectable at doses 100-fold lower than LD50. Kinetic experiments showed that inhibition was mainly caused by a decrease of the Vmax (680 ± 53 vs. 382 ± 23 and 555 ± 27 nmol/15s/mg protein in control and exposed larvae to K2Cr2O7 and fenitrothion, respectively). Inhibition is possibly related to a variation of sodium ions permeability as evidenced by increased membrane lipid peroxidation. Appropriate control experiments ruled out that the observed differences could be due to changes in general features of membrane preparations. Transport inhibition observed in larvae exposed to potassium dichromate was accompanied by changes in ascorbate peroxidase and dehydroascorbate reductase activities, whereas those exposed to fenitrothion displayed an increase in transaminase activity. The possible value of leucine uptake as biochemical biomarker is briefly discussed. Arch. Insect Biochem. Physiol. 55:90–101, 2004. © 2004 Wiley-Liss, Inc.
Journal Article•
TL;DR: The conclusion of this study was that potassium dichromate has obvious teratogenic effect on Vicia faba root tip cells.
Abstract: We studied the aberrant effects of different concentrations of potassium dichromate on Vicia faba root tip cells. The micronucleus and chromosome aberration assay was conducted to determine the micronucleus rate and chromosome aberration rate of Vicia faba root tip cells induced by potassium dichromate. The result indicated that potassium dichromate could increase the micronucleus rate of Vicia faba root tip cells. Within certain range of concentration the rate of micronucleus was found to be increased with the increase of potassium dichromate concentration,but beyond this range the rate of micronucleus decreased with further increase of potassium dichromate concentration. The potassium dichromate at different concentrations could increase the cell mitosis index. Besides,it also caused various types of chromosome aberration,and the rates of chromosome aberration were always higher than that of the control group. The conclusion of this study was that potassium dichromate has obvious teratogenic effect on Vicia faba root tip cells.
Patent•
10 Mar 2004
TL;DR: A superconducting heat transfer medium has three basic layers, the first layer being various combinations of cobalt, manganese, beryllium, strontium, rhodium, copper, beta-titanium, potassium, boron, calcium, and the dichromate radical as discussed by the authors.
Abstract: A superconducting heat transfer medium that has three basic layers, the first layer being various combinations of sodium, beryllium, a metal such as manganese or aluminum, calcium, boron and dichromate radical; the second layer formed over the first layer and being various combinations of cobalt, manganese, beryllium, strontium, rhodium, copper, beta -titanium, potassium, boron, calcium, a metal such as manganese or aluminum and the dichromate radical; and the third layer formed over the second layer and being various combinations of rhodium oxide, potassium dichromate, radium oxide, sodium dichromate, silver dichromate, monocrystalline silicon, beryllium oxide, strontium chromate, boron oxide, beta -titanium and a metal dichromate, such as manganese dichromate or aluminum dichromate. The three layers can be applied to a conduit and then heat polarized to form a superconducting heat transfer device that transfers heat without any net heat loss, or can be applied to a pair of plates having a small cavity relative to a large surface area to form a heat sink that can immediately disperse heat from a heat source.
01 Jan 2004
TL;DR: In this paper, the effects of preservatives on milk component analysis using infrared spectrophotometric method were investigated, and it was concluded that bronopol, potassium dichromate and sodium azide are effective preservatives for raw milk components analysis.
Abstract: The effects of preservatives on milk component analysis using infrared spectrophotometric method were investigated. Raw milk samples from sixty farms were collected. Thirty ml from each milk sample was kept in plastic vial containing either 0.02 % bronopol, 0.40 % potassium dichromate or sodium azide tablet (0.03 %) as preservatives. All milk sub-samples were stored under refrigeration at 4∞C then analyzed for milk components at 0, 7, 14, 21 and 28 days of storage. Control samples (without preservative) were analyzed only at 0 day. The means of milk fat, protein, lactose and total solids for the non-preserved milk at 0 day storage were 4.10, 3.00, 4.84 and 12.65 %, respectively. Analysis result of milk components among the control, milk preserved with bronopol and milk preserved with potassium dichromate showed no statistical different at 0 day storage. At this storage day, however, raw milk with sodium azide had lower (P<0.01) fat, protein and total solids. Prolonged storage of milk preserved with the three chemicals over 7 days illustrated a potential decline in most components analyzed. Changing pattern of the analysis results of milk preserved with the three respective chemicals at 28 days when compared with those of 0 day storage were -5.39, -4.79 and -8.36 % for fat, -0.30, -1.17 and +0.13 % for protein, -1.22, -0.91 and -0.91 % for lactose, and -2.45, -2.29 and -3.11 % for total solids. It is concluded that bronopol, potassium dichromate and sodium azide are effective preservatives for raw milk component analysis by infrared spectrophotometry. However, commercial sodium azide in the tablet form contains sodium salt, which can depress milk component analysis result. In addition, preserved raw milk samples should be kept under refrigeration at 4∞C and analyzed within 7 days.
01 Jan 2004
TL;DR: In this article, a simple kinetic spectrophotometric method for the determination of oxalic acid has been described, based on its catalytic effect on the oxidation of pyrocathecol violet (PCV) with potassium dichromate in acidic media.
Abstract: A simple kinetic spectrophotometric method for the determination of oxalic acid has been described, based on its catalytic effect on the oxidation of pyrocathecol violet (PCV) with potassium dichromate in acidic media. The reaction was monitored photometrically by measuring the decrease in absorbance of PCV at 450 nm. The influence of acid, PCV concentration, dichromate concentration, and temperature were studied and optimized completely. Under the optimum condition, a calibration graph from 0.08 to 1.3 µg/mL of oxalic acid with a detection limit of 0.07 µg/mL was obtained. The relative standard deviation for ten replicate measurement of 0.8 µg/mL oxalic acid is 0.8%. The proposed method is fast and simple. The applicability of the method was demonstrated by the determination of oxalic acid in wastewater, spinach, and mushroom samples.
Patent•
16 Dec 2004
TL;DR: In this article, an apparatus for detecting the presence of Gamma-hydroxybutyrate or other drugs in a veverage comprises apparatus wherein cobalt nitrate, oxammonium chloride/ferric chloride, 5% ferric chloride and saturated potassium dichromate, toluene/cobalt thiocyanate, chromium (IV) oxide/sulphuric acid carbodiimide salts in combination with oxamonium salts and or lacmoid is supported on a substrate.
Abstract: Apparatus for detecting the presence of foreign substances in a beverage. The apparatus for detecting the presence of Gamma-hydroxybutyrate or other drugs in a veverage comprises apparatus wherein cobalt nitrate, oxammonium chloride/ferric chloride, oxammonium sulphate/ferric chloride, 5% ferric chloride, saturated potassium dichromate, toluene/cobalt thiocyanate, chromium (IV) oxide/sulphuric acid carbodiimide salts in combination with oxammonium salts and ferric chloride, or lacmoid is supported on a substrate. The apparatus for detecting the presence of ketamines or other drugs in a beverage comprises apparatus wherein modified-Dragendorff Reagent is supported on a substrate.
TL;DR: The solubilities of the K2Cr2O7 + CrO3 + KNO3+HNO3 + H2O system at 0 °C, 25 °C and 45 °C were determined, and the phase diagrams were constructed.
Abstract: The solubilities of the K2Cr2O7 + CrO3 + KNO3 + HNO3 + H2O system at 0 °C, 25 °C, and 45 °C were determined, and the phase diagrams were constructed. Furthermore, analyses and discussions are made on the crystalline areas in the phase diagrams. Based on the solubility data, the technique of a new cleaner process for manufacturing chromium trioxide and potassium nitrate simultaneously by decomposing potassium dichromate with nitric acid was evaluated.
01 Jan 2004
TL;DR: In this paper, a rank order for the irritancy of metal compounds can be inferred from the patch test concentrations recommended as non-irritating for the purpose of cutaneous allergy testing: potassium dichromate 0.5%, copper sulfate, cobalt chloride and palladium chloride ex equo: 1% in aqueous solution, and nickel sulfate: 5% in petrolatum.
Abstract: Data on the dermal irritation by copper and its compounds is scant, and its irritancy has not been determined, e.g., in terms of an irritant dose ID50. Irritancy of copper can only be comparatively characterized in relation to other metal salts. A rank order for the irritancy of metal compounds can be inferred from the patch test concentrations recommended as non-irritating for the purpose of cutaneous allergy testing: potassium dichromate 0.5% in petrolatum; copper sulfate, cobalt chloride and palladium chloride ex equo: 1% in aqueous solution, and nickel sulfate: 5% in petrolatum.
TL;DR: Zinc potassium chromate (4Zn·O4CrO3·K2O·3H2O) was prepared using zinc salt solution, sodium hydroxide and potassium dichromate solutions.
Abstract: Zinc potassium chromate (4Zn·O4CrO3·K2O·3H2O) was prepared using zinc salt solution, sodium hydroxide and potassium dichromate solutions. The pigment synthesised was investigated by various methods. Upon heating, this pigment underwent decomposition to form ZnCr2O4, K2CrO4 and ZnO. The pigment obtained was successfully used in the preparation of glaze and then on a tile. The L*, a* and b* values of the fired glaze were 71.607, 2.695 and 67.327, respectively.
Journal Article•
TL;DR: In this article, the determination of COD in wastewater by potassium dichromate colorimetric method was discussed and results showed the detection limit was 6mg/L, and errors were bigger under concentration of cOD below 24mg/l.
Abstract: The determination of COD in wastewater by potassium dichromate colorimetric method was discussed. Results showed the detection limit was 6mg/L, and errors were bigger under concentration of COD below 24mg/L.The practice process demonstrated this method was simple, fast, stable, cost effective, and monitoring apparatus was portable.
01 Jan 2004
TL;DR: In this article, a rapid and simple method based on visible spectrometric procedure is proposed for the determination of COD in wastewater treatment system, which is an improvement of standard method to determine COD.
Abstract: A rapid and simple method based on visible spectrometric procedure is proposed for the determination of COD in wastewater treatment system. It is an improvement of standard method to determine COD, i.e. determination of excess dichromate (Cr -2O + {2- } -7) by visible spectrometry at 442 nm. The absorbance value (A) of Cr -2O + {2- } -7 and the concentration of COD have linear relation by computer analogy, so COD is determined indirectly in this way. Some influencing factors, such as the refluxing time, the amount of wastewater sample and potassium dichromate, sulfuric acid concentration are investigated, respectively. The result shows that when the concentration of COD in wastewater sample is in the range of 65~(650 mg·L + {-1 }), the results obtained by using the method presented exhibit good agreement with those given by the standard method of COD determination, and the relative error is less than 5.0%. The viability of this method is demonstrated by analyzing two kinds of synthetic wastewater and five kinds of industrial wastewater, and it proves to be a rapid and accurate method for COD determination.
TL;DR: In this article, the effects of various concentrations of metal salts, pH of the printing paste, and the thickening agent on the color strength and fastness properties of the printed fabrics were studied to determine the optimum printing conditions.
Abstract: Acrylic fabrics were pretreated with metal salts (aluminum sulfate, copper sulfate, ferrous sulfate, and potassium dichromate) in different concentrations. The tensile strength, elongation, and moisture regain of pretreated and untreated samples were examined. The effects of various concentrations of the metal salts, the pH of the printing paste, and the thickening agent on the color strength and fastness properties of the printed fabrics were studied to determine the optimum printing conditions. The pretreatment improved the printability of acrylic modified with a cationic dye and the fastness properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 130–134, 2004
TL;DR: The rate of reduction of Cr(VI) to Cr(III) in 0.05 M K2Cr2O7 has been studied and was found to be first order and to decrease with the addition of amines.
TL;DR: The solubilities of the K2Cr2O7 + CrO3 + KNO3+HNO3 + H2O system at 0 °C, 25 °C and 45 °C were determined, and the phase diagrams were constructed.
Abstract: The solubilities of the K2Cr2O7 + CrO3 + KNO3 + HNO3 + H2O system at 0 °C, 25 °C, and 45 °C were determined, and the phase diagrams were constructed. Furthermore, analyses and discussions are made on the crystalline areas in the phase diagrams. Based on the solubility data, the technique of a new cleaner process for manufacturing chromium trioxide and potassium nitrate simultaneously by decomposing potassium dichromate with nitric acid was evaluated.