Potassium Permanganate In Sulfuric Acid Research Articles

Magnetoresistance of graphite nanoplatelets with different structure

The magnetoresistance of bulk specimens of graphite nanoplatelets obtained by different methods is studied in magnetic fields up to 2.2 T. It has been established that magnetoresistance is negative for graphite nanoplatelets prepared by chemical treatment of source graphite with a solution of potassium permanganate in sulfuric acid. This negative magnetoresistance can be explained in terms of the model of charge carrier's weak localization in a system with imperfect structure. It has been established that the magnetoresistance is positive and independent of temperature for graphite nanoplatelets produced by sonication method. Moreover, magnetoresistance is linear relative to a magnetic field in fields above ∼0.7 T. It is shown that linear magnetoresistance can be explained in the terms of the Abrikosov's model of quantum linear magnetoresistance.

Brodie's or Hummers' Method: Oxidation Conditions Determine the Structure of Graphene Oxide.

Synthesis and studies of graphite oxide started more than 150 years ago and turned into a boom by the measurements of the outstanding physical properties of graphene. A series of preparation protocols emanated trying to optimize the synthesis of graphene oxide in order to obtain a less defective material, as source for graphene. However, over-oxidation of the carbon framework hampered establishing structure-property relationships. Here, the fact that two different synthetic methods for graphene oxide preparation lead to very similar types of graphene oxide with a preserved graphene lattice is demonstrated. Either sodium chlorate in nitric acid (similar to Brodie's method) or potassium permanganate in sulfuric acid (similar to Hummers' method) treatment are possible; however, reaction conditions must be controlled. With a preserved carbon lattice analytical differences between the samples relate to the altered on-plane functionality. Consequently, terming preparation protocols "according to Brodie's/Hummers' method" is not sufficient.

Mercury levels in hair samples of dentists: A comparative study in Sri Lanka.

Elemental mercury is widely used in dentistry as dental amalgam. Hair samples constitute preferred biomarkers to determine the index of mercury exposure. In the absence of any published studies, the aim of the present study was to ascertain the level of mercury in a selected sample of dentists and controls in Sri Lanka. Hair samples (.7g) from dentists working in and around the Colombo district in Sri Lanka (n=50) and controls (n=50) were digested with sulfuric acid-potassium permanganate solution, and reduced to metallic mercury with stannous chloride. Digested samples were analyzed for mercury using an atomic absorption spectrophotometer. The average mercury contents of the test and control samples (n=50 each) were 5.36±2.64ppb and 3.1±1.99ppb, respectively. Based on the estimated ratio of mercury in hair to blood in humans as 250:1, the average content of mercury in the blood of the two groups could be .02ppb and .01ppb, respectively. The number of years in dentistry and number of amalgam restorations performed within 1week were not correlated with the hair concentration of mercury. As the values of both groups were well below 10ng/mL (10ppb), within the concentrations considered as normal, mercury use was not considered an occupational hazard for dentists.

Oxidative peeling of carbon black nanoparticles

We demonstrate that layered carbon black nanoparticles can be oxidatively peeledviathe reaction with potassium permanganate in sulfuric acid.

Sequential Flow Membraneless Microfluidic Fuel Cell with Porous Electrodes

A novel convective flow fuel cell with porous electrodes is described. In this fuel cell design, the fuel (formic acid in sulfuric acid) flows radially outward through a thin disc anode and across a gap to a ring shaped cathode. The oxidant (potassium permanganate in sulfuric acid) is introduced into the gap and advects radially outward through the cathode. This fuel cell differs from previous designs in that the reactants flow in series rather than in parallel. The flow velocity field is examined using microscale particle image velocimetry and shown to be nearly axisymmetric and steady. The results show that increasing the electrolyte concentration and flow rate reduce the cell Ohmic resistance and mass transport losses, resulting in larger peak power densities. Additionally, the fuel utilization decreased with higher flow rates, and increased with higher ionic strength solutions.

Flow Injection Chemiluminescence Analysis of Some Penicillins by Their Sensitizing Effect on the Potassium Permanganate-Glyoxal Reaction

A new chemiluminescence method using flow injection is described for the determination of four penicillins, namely: phenoxymethylpenicillin potassium, amoxicillin, ampicillin, and ampicillin sodium. The method is based on sensitizing effect of these drugs on the chemiluminescence reaction of potassium permanganate in sulfuric acid with glyoxal. The different experimental parameters affecting the chemiluminescence intensity were carefully studied and incorporated into the procedure. The method allows the determination of 0.1-1.0 microg/ml phenoxymethylpenicillin potassium, 0.1-1.0 microg/ml amoxicillin, 0.1-1.0 microg/ml ampicillin, and 0.1-1.0 microg/ml ampicillin sodium. The method was successfully applied to the determination of four penicillin antibiotics in pharmaceutical preparations.

Flow injection-chemiluminescence determination of octyl dimethyl PABA in sunscreen formulations

A sensitive flow injection (FI) procedure was developed for the determination of the UV-filter octyl dimethyl PABA in sunscreen formulations based on its chemiluminescence (CL) induced by potassium permanganate in sulfuric acid. Both second-order and log–log calibration graphs can be used to perform the analysis. Ninety injections per hour can be carried out, which means a sample throughput of 18 h −1 if five injections per solution are performed. The limit of detection (3 σ) was 25 ng ml −1. The interference effects of the excipient and other UV filters are studied. Sunscreen formulations containing octyl dimethyl PABA were analysed by both the proposed FI-CL method and a liquid chromatography reference method. The two methods gave comparable results.

Potassium Permanganate Can Be Used For Degrading Hazardous Compounds

Solutions of potassium permanganate in 3 M sulfuric acid, 1 M sodium hydroxide solution, and water can be used to degrade hazardous compounds. Excess oxidant can be removed by using sodium metabisulfite. Manganese, a carcinogen and mutagen, can be removed from the final reaction mixtures by making these mixtures strongly basic. Aqueous dilution causes the soluble potassium sulfate to dissolve while still allowing the insoluble manganese compounds to be removed by filtration and so reduces the weight of precipitate. In all cases the amount of manganese left in the filtrates was less than 2 ppm and the reaction mixtures were nonmutagenic. When ethanol was used as a test compound, degradation was much more rapid when the solvent was 3 M sulfuric acid or 1 M sodium hydroxide solution than when the solvent was water. However, the variation of the rate of reaction with pH depends on the nature of the substrate. Thus the effectiveness of the various methods may vary for other substrates. Potassium permanganate in sulfuric acid was used to degrade four polycyclic heterocyclic hydrocarbons. Destruction was greater than 99.9% and the final reaction mixtures contained no more than 0.5 ppm manganese and were not mutagenic. By modifying the work-up procedures to remove manganese from the final reaction mixture, procedures previously developed for degrading hazardous compounds can still be employed.

The Safe Disposal of Diaminobenzidine

Abstract Diaminobenzidine is a mutagen and possible carcinogen which is widely used in microscopy. The disposal of unneeded bulk quantities and aged working solutions is a problem for many laboratories. A number of methods for the treatment of diaminobenzidine for safe disposal were evaluated. The methods tested were oxidation with potassium permanganate in sulfuric acid, treatment with hydrogen peroxide in the presence of horseradish peroxidase, treatment with sodium hypochlorite, and treatment with sodium nitrite and hypophosphorous acid. The methods were tested to see that the compound was completely degraded and that only nonmutagenic reaction mixtures were produced. Two methods can be recommended for general use: destruction using potassium permanganate or using hydrogen peroxide in the presence of horseradish peroxidase. These procedures can be used for diaminobenzidine in tris(hydroxymethyl) aminomethane or phosphate buffer or for bulk quantities. The diaminobenzidine is completely destroyed (less ...

Reductive destruction of dacarbazine, procarbazine hydrochloride, isoniazid, and iproniazid

Reductive destruction of dacarbazine, procarbazine hydrochloride, isoniazid, and iproniazid using nickel-aluminum alloy in basic solution is described. Solutions of dacarbazine 10 mg/mL were prepared by adding dacarbazine 100 mg, citric acid 100 mg, and mannitol 50 mg to 10 mL of water. Aqueous solutions of procarbazine hydrochloride 10 mg/mL were prepared from commercially available capsules, and aqueous solutions of isoniazid 10 mg/mL and iproniazid 5 mg/mL were prepared from powdered drug. Reductive destruction of drugs was accomplished by mixing each solution with an equal volume of 1 M potassium hydroxide solution and adding 1 g of nickel-aluminum alloy for each 20 mL of basified solution. The resulting mixtures were stirred for 20 hours (96 hours for iproniazid) and analyzed by high-performance liquid chromatography and gas chromatography for the presence of residual drug and degradation products. Dacarbazine solutions were also subjected to destruction by photolysis and by oxidation using potassium permanganate in sulfuric acid, and the results were compared with those obtained by reductive destruction. All reaction mixtures were tested for mutagenicity in Salmonella strains. All drugs subjected to reductive destruction were completely degraded to the limits of detection of the assay and produced only nonmutagenic reaction mixtures. The only acceptable results for dacarbazine were obtained by the reductive destruction method. Reduction of dacarbazine, procarbazine hydrochloride, isoniazid, and iproniazid with nickel-aluminum alloy in dilute base appears to be a good method for the destruction of these toxic compounds.

Oxidative destruction of hydrazines produces N-nitrosamines and other mutagenic species.

As part of the joint International Agency for Research on Cancer-National Cancer Institute program for the evaluation and development of methods for the degradation of chemical carcinogens, four oxidative techniques for the degradation of hydrazines were investigated. The oxidizing agents used were as follows: sodium hypochlorite, calcium hypochlorite, potassium iodate, and potassium permanganate in sulfuric acid. In each case, at least 99% of the hydrazine initially present was destroyed; however, the potential usefulness of these methods was compromised by the formation (in some reaction mixtures) of carcinogenic N-nitroso compounds and/or unknown mutagenic species. Oxidative degradation of hydrazines is recommended only for the decontamination of glassware and for the treatment of spills, for which reductive degradation methods are not suitable.

Oxidative Destruction of Hydrazines Produces N-Nitrosamines and Other Mutagenic Species

As part of the joint International Agency for Research on Cancer-National Cancer Institute program for the evaluation and development of methods for the degradation of chemical carcinogens, four oxidative techniques for the degradation of hydrazines were investigated. The oxidizing agents used were as follows: sodium hypochlorite, calcium hypochlorite, potassium iodate, and potassium permanganate in sulfuric acid. In each case, at least 99% of the hydrazine initially present was destroyed; however, the potential usefulness of these methods was compromised by the formation (in some reaction mixtures) of carcinogenic N-nitroso compounds and/or unknown mutagenic species. Oxidative degradation of hydrazines is recommended only for the decontamination of glassware and for the treatment of spills, for which reductive degradation methods are not suitable.

Assay for mercurial preservatives in biological products by cold-vapor atomic absorption spectrophotometry

The cold-vapor method of flameless atomic absorption spectrophotometry was applied to the rapid, accurate and precise assay for mercurial preservatives in vaccines and other biological products through the quantitation of mercury. Sample dilution or a microliter sample size permitted the use of an uncomplicated cold concentrated sulfuric acid-potassium permanganate digestion procedure. This digestion procedure freed the mercury from the organic material in the organomercury preservative compounds and from the sample matrices which ranged in complexity from diluents with preservatives to toxoids, influenza virus vaccines and globulins. Microgram amounts of mercury were detected in some rubber components of final container closure-systems in contact with liquid products containing mercurial preservatives.

An Improved Procedure for Wet Oxidation of the 14C Nbs Oxalic Acid Standard

An improved procedure for wet combustion of 14C NBS oxalic acid standard has been devised which gives consistent high carbon yields and average δ13C values of —19.1‰. The principal cause of fractionation in earlier attempts to prepare CO2 by the wet oxidation method was the inexact nature of the end-point. The new procedure employs a chocolate-brown end-point by adding 5ml more of the sulfuric acid-potassium permanganate solution after the initial reddish brown end-point is reached. The sulfuric acid-potassium permanganate solution is added to the NBS oxalic acid in a steady drop-wise flow, heat is applied to the generating apparatus, and a cycling technique is utilized to collect the CO2.Fifteen samples of the NBS oxalic acid were processed. The per cent carbon yields range from 98.8 to 100.9% with an average of 99.7% and an average δ13C of —19.12‰. The results obtained by this procedure are much more consistent than previous results obtained in several laboratories by direct combustion.

Rapid Analysis for Total Mercury in Urine and Plasma by Flameless Atomic Absorption Analysis

Abstract A rapid, simplified method is described for analysis for total mercury in urine and plasma. A sulfuric acid—potassium permanganate digestion of small sample volumes efficiently prepares them for measurement of both organic and inorganic mercury, which can be done at the rate of about 100 samples per hour.

γ-Butyrolactoneの利用研究 (第10報)

2, 5-Dimethoxyaniline and α-acetyl-γ-butyrolactone were reacted to 2-[1-(2, 5-dimethoxyphenylimino) ethyl]-γ-butyrolactone (I), which was later treated with phosphorous oxychloride to give 2-methyl-3-(2-chloroethyl)-4-chloro-5, 8-dimethoxyquinoline (II). Treatment of (II) with either acetic acid or thiourea afforded the corresponding 4-methyl-6, 9-dimethoxy-2, 3-dihydrofuro [3, 2-c]-quinoline (III) and 4-methyl-6, 9-dimethoxy-2, 3-dihydrothieno [3, 2-c] quinoline (VI), respectively. (III) and (VI) were treated with 47% hydrobromic acid to give 4-methyl-2, 3-dihydrofuro [3, 2-c] quinoline-6, 9-diol hydrobromide (IV) and 4-methyl-2, 3-dihydrothieno [3, 2-c] quinoline-6, 9-diol hydrobromide (VI) which were converted to 4-methyl-2, 3-dihydrofuro [3, 2-c] quinoline-6, 9-dione (V) and 4-methyl-2, 3-dihydrothieno [3, 2-c] quinoline-6, 9-dione (VIII) respectively by the oxidation of potassium permanganate in sulfuric acid.