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Showing papers on "Potassium dichromate published in 2015"


Journal ArticleDOI
TL;DR: The ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal sites, where the temperature may reach ∼70°C is demonstrated.

70 citations


Journal ArticleDOI
TL;DR: The mechanism underlying the favorable effect of Mn(II) observed during Cr( VI) reduction by oxalic acid is revealed and may be helpful in designing a new, environmentally friendly strategy for the remediation of environments contaminated with Cr(VI).

32 citations


Journal ArticleDOI
TL;DR: In this paper, a one-pot method for synthesizing multi-substituted indolizines from α-halo-carbonyl compounds, pyridines and electron deficient alkenes was developed.
Abstract: A one-pot method for synthesizing multi-substituted indolizines from α-halo-carbonyl compounds, pyridines and electron deficient alkenes was developed. A sub-equivalent amount of potassium dichromate was used as an oxidant under base free conditions. The transformation developed should be of economic efficiency.

32 citations


Journal ArticleDOI
19 Aug 2015-Sensors
TL;DR: A novel rapid methodology for determining the chemical oxygen demand (COD) based on a thermal sensor with a flow injection analysis system was proposed and experimentally validated.
Abstract: A novel rapid methodology for determining the chemical oxygen demand (COD) based on a thermal sensor with a flow injection analysis system was proposed and experimentally validated. The ability of this sensor to detect and monitor COD was based on the degree of enthalpy increase when sodium hypochlorite reacted with the organic content in water samples. The measurement results were correlated with COD and were compared against the conventional method using potassium dichromate. The assay required only 5-7 min rather than the 2 h required for evaluation by potassium dichromate. The linear range was 5-1000 mg/L COD, and the limit of detection was very low, 0.74 mg/L COD. Moreover, this method exhibited high tolerance to chloride ions; 0.015 mol/L chloride ions had no influence on the response. Finally, the sensor was used to detect the COD of different water samples; the results were verified by the standard dichromate method.

19 citations


Journal ArticleDOI
TL;DR: After immunostaining followed by TCCA bleaching, the melanin could be completely removed in all 120 malignant melanoma tissue sections, and neither potassium permanganate nor potassium dichromate is an ideal solution, whereas T CCA might be an Ideal solution for melanin bleaching after the immunohistochemical staining of melanin-containing tissues.
Abstract: Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3'-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium permanganate bleaching and potassium dichromate bleaching clearly destroyed DAB, whereas TCCA bleaching had no significant effect on DAB. Therefore, neither potassium permanganate nor potassium dichromate is an ideal solution, whereas TCCA might be an ideal solution for melanin bleaching after the immunohistochemical staining of melanin-containing tissues. After immunostaining followed by TCCA bleaching, the melanin could be completely removed in all 120 malignant melanoma tissue sections. Compared with the control, the DAB intensity was clear, and the tissue structure and cellular nuclei were well maintained. It is worth noting that TCCA should be freshly prepared before each experiment, and used within 2 hours of its preparation. In addition, sections should not be incubated with TCCA for over 30 minutes.

19 citations


Journal ArticleDOI
TL;DR: In this article, the authors described extraction of chromium(VI) through supported liquid membrane (SLM), Celgard 2400, which was impregnated with trioctylphosphine oxide (TOPO) dissolved in toluene.
Abstract: The present study describes extraction of chromium(VI) through supported liquid membrane (SLM), Celgard 2400, which was impregnated with trioctylphosphine oxide (TOPO) dissolved in toluene. The stripping phase was comprised of diphenylcarbazide (DPC) in sulfuric acid (H2SO4) whereas the feed phase consists of potassium dichromate (K2Cr2O7) and hydrogen peroxide (H2O2). The effects of concentrations of chromium, TOPO, DPC, and H2SO4 have been studied in order to evaluate the transport efficiency of chromium(VI) ion. The optimum experimental conditions for the chromium(VI) extraction were established as follows: 19.2 × 10−4 mol L-1 chromium ion, 1.5 mol L-1 H2O2 concentration in the feed phase, 0.1 mol L-1 TOPO concentration in the membrane phase and 0.001 mol L-1 DPC and 1.5 mol L-1 H2SO4 as stripping phase. The measurements of percent recovery, distribution coefficient, flux and permeability were made at the given optimized conditions. The extraction time and membrane stability were also investigated. Extraction efficiency of 80% was recorded in 180 min and the SLM system was found stable up to 10 days. The optimized SLM system was then applied on the paint industry wastewater; about 80% of chromium(VI) was successfully removed from the wastewater.

18 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of chromium (both CrIII and CrVI) on the oxidative damages and the induction of antioxidant defence in turnip was studied, and the extent of oxidative damage was most in dichromate as it caused a maximum increase in lipid peroxidation and H2O2 concentration in leaves of turnip plants.
Abstract: Effect of chromium (both CrIII and CrVI) were studied on the oxidative damages and the induction of antioxidant defence in turnip. For this purpose turnip (Brassica rapa L.) plants were grown in refined sand under three different sources of chromium, i.e., chromium sulphate (CrIII), potassium chromate (CrVI) and potassium dichromate (CrVI) supplied at 250 µM concentrations for 4, 24 and 168 h (7 days) after 50 days of growth in normal nutrition. The extent of oxidative damage was most in dichromate as it caused a maximum increase in lipid peroxidation and H2O2 concentration in leaves of turnip plants. The growth and biomass of plants decreased, while the levels of chloroplastic pigment and iron increased in plants supplied CrVI (both potassium chromate and potassium dichromate). Exposure of plants to Cr led to increase in Cr concentration, more in the roots than in shoots. Excess supply of Cr (chromium sulphate, potassium chromate and potassium dichromate), though inhibited peroxidase activity (at 4 and 168 h exposure), stimulated catalase, ascorbate peroxidase and superoxide dismutase activities. Localization of different isoforms of APX and SOD on native gels revealed activation of certain isoform in the Cr-treated plants.

16 citations


Journal ArticleDOI
TL;DR: The study indicated hazardous effect of the hexavalent chromium to fish and other aquatic organisms and indirectly to human beings.
Abstract: The present study was undertaken to investigate the genotoxicity and mutagenicity of sublethal concentrations of hexavalent chromium (potassium dichromate) in the Indian major carp, Labeo rohita. The 96 h LC50 value of potassium dichromate estimated was 118 mg L−1 by probit analysis using SPSS (version 16.0) software. Based on 96 h LC50 value, three sublethal test concentrations of potassium dichromate (29.5, 59.0 and 88.5 mg L−1) were selected and specimens were exposed in vivo to these test concentrations for 96 h. The mutagenic and genotoxic effects of potassium dichromate were evaluated in gill and blood cells using micronucleus (MN) test and comet assay. In general, significant (p < 0.05) effects due to the concentrations and the exposure durations were observed in exposed specimens. The MN induction was highest at 96 h at all the test concentrations in the peripheral blood. A similar trend was observed for the DNA damage, measured in terms of percentage of tail DNA, in erythrocyte and gill c...

15 citations


Journal ArticleDOI
TL;DR: The accuracy of the standardization of a sodium thiosulfate solution by potassium dichromate was discussed from the apparent assays of potassium dichromaate under different measurement conditions.

9 citations


Journal ArticleDOI
TL;DR: In this paper, an effective strategy using potassium dichromate lotion to activate surfaces of commercial carbon papers leading to enhanced electrochemical capacitances was reported, which offers a feasible pathway to make commercial carbon paper a promising candidate for practical supercapacitors and is expected to extend to other carbon based electrode materials.

9 citations


Journal Article
TL;DR: Investigating the toxic effects of Hexavalent chromium (VI) on PC12 cells indicated neurotoxic effects of Cr (VI), however increased production of ROS and lipid peroxidation in Cr ( VI) treated groups demonstrated that oxidative stress might be involved in neurotoxicity ofCr (VI).
Abstract: Objective: Hexavalent chromium [Cr (VI)] compounds are well-known environmental contaminants generated from industrial processes. Several studies have reported the harmful effects of Cr (VI) on different organs, however, little is known about neurotoxic effects of Cr (VI). The aim of this study is to investigate the toxic effects of Cr (VI) on PC12 cells. Methods : PC12 cells were cultured following standard protocol and exposed to various concentrations (1-100 μM) of potassium dichromate (K2Cr2O7) for 24, 48 and 72 h. After exposure, cell viability was measured by the MTT assy. Also following exposure, production of reactive oxygen species (ROS) and lipid peroxidation were measured. Results: Potassium dichromate induced significant cell death in PC12 cells. The IC50 values for cytotoxicity were 22.02 for 24 h, 1.88 for 48 h, and 1.85 for 72 h of exposure. Significant differences between IC50 for 24 h of exposure compared to 48 and 72 h of exposure were observed (p<0.05). ROS production and lipid peroxidation significantly increased in the Cr (VI) treated groups compared to the control group (p<0.05). Conclusion: The results indicated that Cr (VI) induced dose and time dependent cytotoxicity in PC12 cells which indicated neurotoxic effects of Cr (VI). Mechanisms of Cr (VI) induced toxicity have not been fully determined, however increased production of ROS and lipid peroxidation in Cr (VI) treated groups demonstrated that oxidative stress might be involved in neurotoxicity of Cr (VI).

Journal ArticleDOI
TL;DR: Cell growth was affected by the presence of chromium added at the beginning of cultures, and the best growth rates were obtained at lower metal concentrations in the medium, including hexavalent chromium.
Abstract: Microalga biomass has been described worldwide according their capacity to realize biosorption of toxic metals. Chromium is one of the most toxic metals that could contaminate superficial and underground water. Considering the importance of Spirulina biomass in production of supplements for humans and for animal feed we assessed the biosorption of hexavalent chromium by living Spirulina platensis and its capacity to convert hexavalent chromium to trivalent chromium, less toxic, through its metabolism during growth. The active biomass was grown in Zarrouk medium diluted to 50% with distilled water, keeping the experiments under controlled conditions of aeration, temperature of 30°C and lighting of 1,800 lux. Hexavalent chromium was added using a potassium dichromate solution in fed-batch mode with the aim of evaluate the effect of several additions contaminant in the kinetic parameters of the culture. Cell growth was affected by the presence of chromium added at the beginning of cultures, and the best grow...

Journal Article
01 Nov 2015-in Vivo
TL;DR: The findings indicate that at the concentration tested, the chromium compound is a clastogenic as well as an aneugenic in animal and plant bioindicators.
Abstract: Background Chromium typically occurs in two oxidation states in the natural environment, Cr(3+) [Cr(III)] and Cr(6+) [Cr(VI)]. Out of the two chromium species, Cr(VI) is the most mobile, labile and toxic. Hexavalent chromium [Cr(VI)] compounds are classified by the International Agency for Research on Cancer (IARC) as carcinogenic agents to humans. The main source of release of chromium in aquatic ecosystems is related to the industrial application of this metal in metallurgies, tanneries, and in the manufacturing of paints and dyes. The ecotoxicology of Cr(VI) is linked to its environmental persistence and the ability to induce adverse effects in biological systems. In the present study, we evaluated mutagenic effects of Cr(VI) in animal and plant bioindicators. Materials and methods We evaluated primary DNA damage and frequencies of micronuclei (MN) and morphological nuclear abnormalities (NA) in erythrocytes in peripheral blood of the fish Oreochromis niloticus exposed to potassium dichromate at 12 mg l(-1). The genotoxicity and cytotoxicity of Cr(VI) in the onion (Allium cepa) test were also assessed. Results The comet assay showed a significant increase of tailed nucleoids in the erythrocytes of fish treated with K2Cr2O7; MN frequency was also increased in the treatments; cytotoxicity of a low concentration of potassium dichromate, however, was not confirmed. Conclusion The combination of both systems - animal and plant - is adequate and advantageous for mutagenicity evaluation. The findings indicate that at the concentration tested, the chromium compound is a clastogenic as well as an aneugenic.

Journal ArticleDOI
TL;DR: The results suggested significant genomic template instability as a measurement of DNA damage and further demonstrated the potential of RAPD as a powerful tool for detecting genotoxicity induced by potassium dichromate in aquatic environments.
Abstract: The present study used the random amplification of polymorphism DNA (RAPD) technique to evaluate possible DNA damage in the blood cells of Cyprinus carpio exposed to potassium dichromate. Test specimens were exposed to 3 sublethal test concentrations (93.95, 187.9, and 281.85 mg L^{?1}) of potassium dichromate for a period of 96 h. The samplings were collected at 24, 48, 72, and 96 h after exposure. DNA was isolated from the blood samples of both the control and treated groups of C. carpio, and 3 selected decamer primers were used for RAPD-PCR. In comparison to the control, potassium dichromate-treated groups showed differences in RAPD profiles with respect to the disappearance of several bands and the appearance of new ones. There was a significant (P < 0.05) difference between 72 and 96 h after exposure with respect to genomic template stability. The variation in RAPD profiles indicated both time- and concentration-dependent relationships. The results suggested significant genomic template instability as a measurement of DNA damage and further demonstrated the potential of RAPD as a powerful tool for detecting genotoxicity induced by potassium dichromate in aquatic environments.

Journal ArticleDOI
TL;DR: Ginseng has a protective effect against potassium dichromate-induced nephrotoxicity as it has antioxidant, anti-inflammatory, and antiapoptotic activities.
Abstract: Background Chromium is a heavy metal used in painting, dyes, and leather tanning industries. Potassium dichromate Cr6+ has demonstrated ability to induce nephrotoxicity associated with oxidative stress in humans and animals. Ginseng is one of the most popular herbal remedies, with a wide range of beneficial therapeutic effects. Objective The aim of the study was to evaluate the effect of potassium dichromate on the convoluted tubules of adult male albino rats and the possible protective role of ginseng. Materials and methods Forty adult male rats were divided equally into four groups (10 rats for each): Group I was the control group. In group II (the ginseng group), rats received a daily oral dose of ginseng at 100 mg/kg body weight/day by means of a gastric tube for 3 weeks. In group III (the potassium dichromate group), rats received a single subcutaneous injection of potassium dichromate at 15 mg/kg body weight. In group IV (the potassium dichromate and ginseng group), rats received potassium dichromate and ginseng for 3 weeks. Kidney specimens were prepared for light microscopic examination {stained with (H&E), Masson’s trichrome, immunohistochemical detection of caspase-3}. Semithin and ultrathin sections were prepared for electron microscopic examination. Results Group III showed degeneration and necrosis of cells of the renal tubules (proximal and distal) with tubular dilatation, an increase in collagen fibers around degenerated convoluted tubules, and cell apoptosis (highly expressed caspase-3). Electron microscopic results showed marked disrupted brush border of proximal convoluted tubules and disturbance of the basal infoldings of distal convoluted tubules. The cytoplasm had mitochondria that were irregular in shape and variable in size and large electron-dense particles. The smooth endoplasmic reticulum membrane revealed whorly appearance around the degenerated organelles. Group IV showed improvement in the light and electron microscopic changes described before. Conclusion Ginseng has a protective effect against potassium dichromate-induced nephrotoxicity as it has antioxidant, anti-inflammatory, and antiapoptotic activities. We advice the workers who deal with chromium to take enough doses of ginseng to protect themselves from its side effects.

Journal Article
TL;DR: Results showed that Potassium dichromate (K2 Cr2 O7) is highly teratogenic metal and it’s deteriorating affects increase with increase in its concentration.
Abstract: The liver plays vital role in metabolism and act, as a storage center of many substances while kidney function is to maintain homeostasis. Any damage to liver and kidney tissue will induce abnormalities in this process and ultimately can result in mortality of fish. The objective of present study was to identify the degree and damage to the histological changes of Common carp (Cyprinus carpio) liver and kidneys exposed to Potassium dichromate (K2Cr2O7). Fish samples were exposed to 2 doses viz 5 and 10 mg.L -1 designated as P1, P2 while P0 was control. 16 days exposure of Potassium dichromate (K2Cr2O7) induced changes in liver tissue of fish were coagulative necrosis, focal area of necrosis, dilation and congestion in blood sinusoid, aggregations of inflammatory cells between the hepatocytes, and degeneration of parenchyma cell while haemosiderin and aggregations of inflammatory cells, dilation in the capillary tubes of renal tubules and hemorrhage were observed in kidney of Common carp (Cyprinus carpio) when exposed to sub lethal concentration of Potassium dichromate (K2Cr2O7) with respect to control showing normal histology. Present study results showed that Potassium dichromate (K2 Cr2 O7) is highly teratogenic metal and it’s deteriorating affects increase with increase in its concentration.

Patent
29 Apr 2015
TL;DR: In this paper, a corrosion resistant and resistance-reduction conductive concrete for acid soil areas is proposed. But the concrete is not suitable for the transmission line grounding grid, as it can not be used for not only reducing the grounding resistance but also improving the corrosion resistance of a grounding electrode.
Abstract: The invention relates to the field of conductive concrete and particularly relates to corrosion-resistant and resistance-reduction conductive concrete for acid soil areas The corrosion-resistant and resistance-reduction conductive concrete is prepared from the following raw materials: cement, polyaniline and a filler, wherein the polyaniline is composed of the following components in parts by weight: 20-40 parts of aniline, 5-15 parts of acidic catalyst, 30-40 parts of oxidant and 3-20 parts of solvent; the filler is one or more of sand, stone, fly ash and grey stone; the acidic catalyst is one or more of hydrochloric acid, phosphoric acid, picric acid, dodecylbenzene sulfonic acid, dinonylnaphthalenesulfonic acid sol and succinic acid dioctyl phthalate sulfonic acid; the oxidant is one or more of persulfate ammonium, potassium dichromate, hydrogen peroxide, potassium iodate and potassium permanganate; the solvent is one or more of water, ethanol and ethyl acetate; when applied to a transmission line grounding grid, the conductive concrete provided by the invention can be used for not only reducing the grounding resistance, but also improving the corrosion resistance of a grounding electrode, especially in an acidic corrosive soil environment

Journal Article
TL;DR: In this article, carbon cloth was used as an anode for microbial fuel cell (MFC) anodes and the modified anodes yielded maximum power densities of 291.11 mW·m −2 and 438.08 mW ·m−2, 21% and 82% higher than that of the unmodified carbon cloth anode respectively.
Abstract: Oxidants of nitric acid and acidic potassium dichromate were used to modify anode carbon cloths. Modification was completed by first putting the carbon cloth into nitric acid or acidic potassium dichromate at a given temperature, soaking for 30 min and then rinsing with de-ionized water until no variation in pH and finally putting into a vacuum dryer, drying for 12 h. Fourier transform infrared spectroscopy measurements indicated that many hydroxyls and carboxyls were attached on the carbon cloth surface after modification. SEM results showed that the surface of carbon cloth became rougher than the unmodified one. In addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements demonstrated that both modified anodes had excellent electrochemical properties. Using the modified carbon cloths as microbial fuel cell (MFC) anodes respectively, such MFCs yielded maximum power densities of 291.11 mW·m −2 and 438.08 mW·m −2 , 21% and 82% higher than that of the MFC with unmodified carbon cloth anode respectively.

Journal Article
TL;DR: In this article, the authors evaluated the corrosion susceptibility and inhibition of 12Cr martensitic stainless steel in different sulphuric acid and acid chloride concentrations using Potentiodynamic polarization resistance technique.
Abstract: Corrosion susceptibility and inhibition of 12Cr martensitic stainless steel was evaluated in different sulphuric acid and the acid chloride concentrations. Corrosion inhibition of the tested samples in 1M H2SO4 was evaluated using potassium dichromate of different concentrations. The experiments were performed at ambient temperature using potentiodynamic polarization measurement. This paper reports the observed electrochemical response of the tested samples in the strong acid environments. Potentiodynamic polarization resistance technique was used to estimate the corrosion rate, the polarisation resistance and inhibition of the alloy samples tested. The results obtained showed some varied magnitude of corrosion susceptibility for the stainless steel at the different H2SO4 concentrations and also in the acid chloride test media. Corrosion inhibition of the tested samples was effectively achieved using the potassium dichromate inhibitor.

Journal ArticleDOI
TL;DR: In this article, the mechanism of clindamycin phosphate by potassium dichromate in aqueous sulfuric acid medium is studied spectrophotometrically at 25°C at a constant ionic strength of 3.60 m−DM−3.
Abstract: Kinetics and mechanism of oxidation of clindamycin phosphate by potassium dichromate in aqueous sulfuric acid medium is studied spectrophotometrically at 25°C at a constant ionic strength of 3.60 mol dm−3. The stoichiometry of the reaction is determined and it was found that one mole of clindamycin phosphate consumes two moles of chromium(VI) (1:2). The oxidation products are characterized and confirmed by spectral studies such as IR, GC-MS and LC-MS. The reaction is first order each in chromium(VI) and clindamycin phosphate concentrations. An increase in the sulfuric acid concentration causes an increase of the reaction rate. The order with respect to acid concentration is found to be 1.65. From the results of kinetic studies, reaction stoichiometry and product analysis a suitable free radical mechanism is proposed. Based on investigation of the reaction at different temperatures, computation of the activation parameters with respect to the slow step of the proposed mechanism was evaluated.

Patent
11 Nov 2015
TL;DR: In this article, a rapid simultaneous detection method for the content of copper, zinc and iron in gold mud was proposed, where a sample is dissolved by utilizing nitric acid, aqua regia, sulfuric acid and nitric-sulfuric acid.
Abstract: The invention relates to a rapid simultaneous detection method for the content of copper, zinc and iron in gold mud A sample is dissolved by utilizing nitric acid, aqua regia, sulfuric acid and nitric-sulfuric acid; after sulfuric acid is added for smoking, a copper-zinc-iron compound is decomposed to form a corresponding oxide, HAuCl4 is decomposed to form elemental gold, and H [AgCln] is decomposed to form silver chloride; after sulfuric acid is added for dissolving salts, the copper iron zinc oxide is dissolved to form sulfate; after ammonia water is added, silver-copper-zinc is transformed into corresponding ammonia complex ions, iron is transformed into iron hydroxide precipitation, and gold and iron are filtered and then separated from filtrate; after the pH value of the filtrate is adjusted by adding sulfuric acid and ammonia water, sodium chloride is added for precipitation of silver, the silver is recovered by filtering, copper in the filtrate is detected by adopting iodometry, and zinc is detected by adopting an EDTA method; and iron is detected by using a potassium dichromate method The sample consumption is less in a detection process, precious metals can be effectively classified and recovered, the detection process is simplified, the energy consumption is reduced, and the detection efficiency is improved

Journal Article
TL;DR: In this paper, the authors evaluated hepatotoxicity induced by potassium dichromate in chickens via drinking water and found that the liver cells of the liver treated with Cr(VI) were severely dilated and the liver appeared severe inflamed and necrotic.
Abstract: Article history Received: 19 Apr, 2015 Revised: 22 May, 2015 Accepted: 24 May, 2015 Abstract This study evaluated hepatotoxicity induced by potassium dichromate in chickens via drinking water. Seventy-two Hyland Brown male chickens were randomly divided into 4 groups (18 chickens each group): Control group, low-dose (2%LD50) Cr(VI) group, middle-dose (6%LD50) Cr(VI) group, high-dose (10%LD50) Cr(VI) group. Potassium dichromate was given orally via drinking water to the chickens for 42 day. The control group was treated with the same volume of distilled water. Blood biochemical indexes (ALT, AST, GGT), antioxidant indicators (SOD, GSH and MDA) in liver homogenates and pathologic changes in tissues were detected at 14, 28 and 42 day respectively. The levels of serum biochemical indexes (ALT, AST, GGT) increased significantly (P<0.05) in Cr(VI)-treated groups. The activities of SOD and GSH decreased significantly (P<0.05) in the Cr(VI)-treated groups while the content of MDA increased significantly (P<0.05) in the Cr(VI)-treated groups compared to control with the increasing dose and time. The cells of the liver treated with Cr(VI) were severely dilated and the liver appeared severe inflamed and necrotic. The results indicated that Cr(VI) can lead to hepatotoxicity damage in chicken with time and dosedependent relationship.


Patent
07 Jan 2015
TL;DR: In this article, a method for detecting potassium dichromate and ascorbic acid by using a graphene quantum dot probe is described. But the method is not suitable for high-sensitivity detection.
Abstract: The invention discloses a method for detecting potassium dichromate and ascorbic acid by using a graphene quantum dot probe. The method is characterized in that the graphene quantum dot probe is used as a fluorescence probe and by virtue of the characteristics that the fluorescence intensity of the graphene quantum dot probe weakens with the increasing of the concentration of a potassium dichromate solution and increases with the increasing of the concentration of an ascorbic acid solution, high-sensitivity detection is performed and the change value of the fluorescence intensity of the graphene quantum dot probe forms a good linear relationship with both the concentration of the potassium dichromate and the concentration of the ascorbic acid, with the correlation coefficients of 0.994 and 0.996 respectively. The method is easy and convenient to operate, rapid in detection, high in sensitivity and good in selectivity, and can perform online in-situ rapid and sensitive detection on the potassium dichromate and the ascorbic acid in a mixed sample.

Patent
27 May 2015
TL;DR: In this paper, an accurate, energy-saving and consumption reduction method for measuring COD (chemical oxygen demand) is proposed, which comprises the following steps: preparing potassium dichromate standard solution with the concentration of 0.25mol/L; preparing ferroin indicator solution; preparing ammonium ferrous sulfate solution; and preparing sulfuric acid-silver sulfates solution.
Abstract: The invention relates to an accurate, energy-saving and consumption-reduction method for measuring COD (chemical oxygen demand). The method comprises the following steps: preparing potassium dichromate standard solution with the concentration of 0.25mol/L; preparing ferroin indicator solution; preparing ammonium ferrous sulfate solution; preparing sulfuric acid-silver sulfate solution; calibrating the ammonium ferrous sulfate solution, namely, drawing 1mL of potassium dichromate standard solution, adding with water for dilution until reaching 20mL, adding with 3mL of concentrated sulfuric acid, adding with one drop of ferroin indicator solution, placing the ammonium ferrous sulfate solution into a seat type micro burette for titration; weighing 0.04g of mercury sulfate, adding into a HACH transparent threaded pipe, adding with 2mL of water sample, adding with 1mL of potassium dichromate standard solution and 3mL of sulfuric acid-silver sulfate solution simultaneously and placing into a HACH digestion apparatus; performing titration experiment, namely, cooling the solution in the HACH transparent threaded pipe to be at room temperature, transferring the solution into a 50mL conical flask and diluting to reach 20mL with deionized water, adding with one drop of ferroin indicator solution, and titrating with the seat type micro burette, therefore, the COD measurement can be finished. The method is accurate, convenient, safe and environmentally friendly.

Patent
29 Apr 2015
TL;DR: In this paper, a method for detecting potassium dichromate by using a fluorescent carbon dot probe was proposed, which can reach a detection limit of 25*10 mol/L using fluorescence quenching method.
Abstract: The invention discloses a method for detecting potassium dichromate by a fluorescent carbon dot probe The method comprises the following steps: preparing the fluorescent carbon dot probe; preparing a mixed solution of the fluorescent carbon dot probe and a sample solution, and detecting the concentration of potassium dichromate in the mixed solution by a fluorescence quenching method The method has the beneficial effects that a fluorescent carbon dot is used as the probe, when the high sensitivity of potassium dichromate is detected by utilizing the characteristics that fluorescent lights of the fluorescent carbon dot are quenched via potassium dichromate, the detection limit of potassium dichromate can reach 25*10 mol/L, thus the detection process is easy and convenient to operate, high in sensitivity and excellent in selectivity, and the method can be used for detecting potassium dichromate in the mixed sample

Ayoub, Abdulwahid, Bazzaz, Neama, Ali, Ahmad, Noorhan, Chelebi 
01 Jan 2015
TL;DR: The results indicate the safety of small and mild intoxication doses of the potassium dichromate on distribution of Toxocara canis in brain portions of mice.
Abstract: The frequency of the infective larvae of Toxocara canis, the common parasite of the dog was assessed in brain portions of male Albino mice ingested two doses: 200 mg/Kg and 400 mg/Kg of potassium dichromate-hexavalent (VI) as an indicator. Only 2,000 ova of the parasite were inoculated orally to twenty seven healthy young male mice. Frequency of the parasite was tested 13 weeks post-inoculation. Using bio-statistical analysis (one way analysis of variance) the frequency of detected larvae of both doses in the brain portions of the experimental animals showed an insignificant difference (p ≥ 0.05) in comparison with control. The results indicate the safety of small and mild intoxication doses of the potassium dichromate on distribution of Toxocara canis in brain portions of mice.

Patent
20 May 2015
TL;DR: In this article, a blood stabilizer is used for stabilizing a blood sample, which consists of the following components according to concentrations: 10-300micromol/L of beta-cyclodextrin, 15-350micromolate/l of disodium cromoglycate, 0.05-1.5% of lecithin and 2.5-5.0mumol of EDTA tripotassium salt.
Abstract: The invention relates to a blood stabilizer and application thereof. The blood stabilizer is used for stabilizing a blood sample. The blood stabilizer disclosed by the invention comprises the following components according to concentrations: 10-300micromol/L of beta-cyclodextrin, 15-350micromol/L of disodium cromoglycate, 0.01%-0.5% of potassium dichromate, 5-150micromol/L of triflusal, 0.05%-1.5% of lecithin and 2.5-5.0mumol/L of EDTA tripotassium salt, wherein the concentration of potassium dichromate and lecithin is mass percent concentration. The blood stabilizer is capable of stabilizing hemocyte, preventing karyocyte from cracking to avoid releasing DNA in cells, and avoiding increasing the concentration of DNA outside the hemocyte; and meanwhile, the blood stabilizer disclosed by the invention is capable of preventing in vitro degradation of the DNA and preventing blood coagulation.

Journal ArticleDOI
S. M. Sayyah1, H Moustafa1, A H El-Ghandour1, Ahmed Aboud1, M Y Ali1 
TL;DR: In this paper, a molecular mechanism for the oxidation of poly-p-aminophenol using potassium dichromate is proposed, which explains the specific features of polymeric oligomerization and polymerization reactions.
Abstract: The synthesis of poly-p-aminophenol (PPAP) by oxidative chemical polymerization using potassium dichromate as oxidizing agent was carried out. The optimum conditions for the polymerization reaction were investigated. The order of reactions and thermodynamic activation parameters were calculated. A molecular mechanism for the oxidation of p-aminophenol using potassium dichromate is proposed. This mechanism explains the specific features of p-aminophenol oligomerization and polymerization reactions. Spectroscopic studies using IR, UV–vis and elemental analysis have evidenced the structure of polymeric chain. The surface morphology of the obtained polymer was characterized by X-ray diffraction and transmission electron microscopy (TEM). The thermo gravimetric analysis (TGA) was used to confirm the proposed structure and number of water molecules in each polymeric chain unit. Moreover, determinations of dielectric properties of the prepared polymer at the investigated optimum condition were carried out. The a.c conductivity (σ ac ) of (PPAP) was investigated as a function of frequency and temperature. The microscopic conduction mechanism of charge carries over the potential barrier in polymer backbone was found to be classical hopping model. The equilibrium ground state geometric parametric of p-aminophenol (PAP) neutral monomer and radical cation are investigated theoretically using DFT – B3LYP/ 6-311G ** level of calculation. The initiation and propagation steps of oxidative chemical polymerization are theoretically investigated.

01 Dec 2015
TL;DR: The delay in tooth eruption observed after exposure to hexavalent chromium is the result of a lower rate of bone remodeling in the developing alveolus, showing the importance of controlling toxic substances in drinking water.
Abstract: Improperly treated hexavalent chromium-containing industrial wastes contaminate drinking water, potentially affecting children taking breast milk or baby bottles prepared with infant formula. Thus, the aim of the present work was to determine the effect of this toxic on bone activity in the developing alveolus during tooth eruption of suckling Wistar rats intoxicated with potassium dichromate. Experimental animals received a daily dose of 12.5mg/kg body weight of potassium dichromate by gavage for 10 days; controls received an equivalent volume of saline solution. Histologic and histomorphometric studies of the mandible were performed. The data were statistically analyzed using Student's t test; statistical significance was set at a value of p <0.05. Experimental animals exhibited delayed tooth eruption, decreased periodontal width and bone volume, a lower percentage of bone formation surfaces, and higher percentage of quiescent surfaces (p<0.05) compared to controls. The delay in tooth eruption observed after exposure to hexavalent chromium is the result of a lower rate of bone remodeling in the developing alveolus. The obtained results show the importance of controlling toxic substances in drinking water, since their effects may alter the growth and development of subjects who were exposed during early infancy.