Volumetric Studies In Oxidation-Reduction Reactions: Oxidation with ceric sulphate ferrous ethylenediamine sulphate method

Ceric sulphate has been used as an oxidizing agent in acid medium for the indirect volumetric determinations of ferrous ammonium sulphate, cuprous chloride, potassium thiocyanate, sodium thiosulpliate, sodiuin nitrite, hydrogen peroxide, sodium oxalate, hydroquinone and pyruvic acid. The excess of ceric sulphate added to each of the substances in acid medium was titrated with standard ferrous ethylenediamine sulphate solution using ferroin as an indicator.     

Quantitative Separation of Citric Acid From Trichloroacetic Acid on Plates Coated with Calcium Sulphate Containing Zinc Oxide

Abstract

Thin-layer chromatographic behaviour of ten acids on coating of calcium sulphate containing ammonium molybdate, aluminium oxide, calcium carbonate, copper sulphate, ferric chloride, magnesium sulphate, phthalic anhydride, titanium oxide, zinc oxide etc. has been studied. Quantitative separation of citric acid from trichloroacetic acids has been achieved on calcium sulphate containirig zinc oxide in ethyl acetate. Herbicide, trichloroacetic acid can be separated from plant growth regulators such as indole-3-acetic, β-naphthaleneacetic and β-naphthoxy acetic acids and from other organic acids.     

Volumetric studies in oxidation-reduction reactions: Oxidation with chloramine-t. iodine monochloride method

Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium' for the volumetric estimations of potassium iodide, hydrazine sulphate, arscnious oxide, stannous chloride, mercurous chloride, tartar-emetic, potassium thiocyanate and ferrous ammonium sulphate, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Studies in oxidation-reduction reactions: Oxidation with chloramine-b,iodine monochloride method

Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, arsenious oxide, tartar-emetic, mercurous chloride, stannous chloride, potassium thiocyanate, ferrous ammonium sulphate, hydrazine sulphate and hydroquinone, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride.     

Volumetric studies in oxidation-reduction reactions : Oxidation with sodium hypochlorite iodine monochloride method

Alkaline sodium hypochlorite was used as an oxidant to determine arsenious oxide, hydrazine sulphate, ferrous ammonium sulphate, stannous chloride, sodium sulphite, potassium iodide, mercurous chloride, thallous chloride and tartar emetic, by a volumetric method, using iodine monochloride as catalyst and preoxidizer. During these titrations, the normality of the solution with respect to hydrochloric acid was kept between 5N and 7N, Chloroform was used as an indicator. Its pink colour due to the liberation of iodine during the titration turns very pale yellow at the end-point because of the formation of iodine monochloride     

Ion chromatographic determination of selected ions in antarctic ice

Ion chromatography is used to measure the concentrations of chloride, nitrate, sulphate, ammonium and sodium ions at the μg l^?1 level in Antarctic ice and to investigate the occurrence of methanesulphonate, fluoride, formate, acetate and nitrite. Of the latter group of ions, only methanesulphonate was found in measurable concentrations.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent: Iodine monochloride method

The method of preparation of diethylenetetra-ammoniuin sulphatocerate is described. This substance has been used as an oxidant to determine potassium iodide, ferrous ammonium sulphate, arsenious oxide, stannous chloride, hydrazinc sulphate, thallous chloride. hydroquinone and potassium ferrocyanide by a volumetric method, using iodine inonochloride as catalyst and preoxidizer. During these titrations, normality of the solution with respect to hydrochloric acid has been kept at about 6N. Chloroform is used as an indicator. It is 'coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

5:6-Benzoquinaldinic acid as an analytical reagent: Determination of titanium

The reagent 5 :6 -benzoquinaldisic acid precipitates titanium(lV) completely from solution at and above pH 3.0 in the presence of rare earths. Coprecipitation of magnesium and the alkaline earths is easily prevented by the addition of ammonium chloride. Separation from iron(III), thorium or zirconium can be carried out in the presence of complexone III. magnesium sulphate being used as a demasking agent. Separation from aluminium is not possible. The titanium precipitate is not of definite composition and so it is ignited to the oxide before weighing.     

Chlorination of copper-containing raw material by ammonium chloride

A new method of processing the copper-containing raw material to copper(II) oxide was suggested and examined based on the chlorination of copper-containing raw material with ammonium chloride followed by dissolution of copper chloride, precipitation of copper hydroxide from a solution and its calcining to copper(II) oxide. Thermogravimetric analysis of the process was conducted. Kinetics of chlorination of copper(II) oxide by ammonium chloride was experimentally investigated. Technological scheme of the copper-containing raw material processing with ammonium chloride was suggested.     

Steam distillation methods for determination of ammonium,nitrate and nitrite

Steam distillation methods of determining ammonium, nitrate, and nitrite in the presence of alkali-labile organic nitrogen compounds are described. They involve the use of magnesium oxide for distillation of ammonium, ball-milled Devarda alloy for reduction of nitrate and nitrite to ammonium, and sulfamic acid for destruction of nitrite. The methods are rapid, accurate, and precise, and they permit nitrogen isotope-ratio analysis of ammonium, nitrate, and nitrite in tracer studies using ¹⁵N-enriched compounds. They give quantitative recovery of ammonium, nitrate and nitrite added to soil and plant extracts, and appear suitable for analysis of biological materials.     

Molten sodium nitrite—potassium nitrite eutectic: the reaction of some compounds of molybdenum

Molybdenum(VI) oxide, ammonium molybdate and molybdic acid reacted in molten sodium nitrite—potassium nitrite eutectic to form orthomolybdate, nitrogen dioxide and nitric oxide (with nitrate as a secondary product), a more polymerised polymolybdate being formed as an intermediate product. Tungsten(VI) oxide reacted similarly but less rapidly. Molybdenum and tungsten metals reacted to form the orthoxyanion and nitrogen, the latter metal reacting considerably faster and forming smaller amounts of nitric oxide and nitrous oxide. Reaction temperatures and stoichiometries are given and reaction pathways suggested.     

Molten lithium carbonate—sodium carbonate—potassium carbonate eutectic: The reaction of ten main group acidic oxides and oxyanions

The reactions of ten main group acidic oxides and oxyanions with molten alkali metal carbonate eutectics have been studied by thermogravimetry. Products have been identified by IR and Raman spectroscopy and stoichiometries suggested for the several reactions as oxide is progressively incorporated. Ultimately the tetrahedral ortho-oxyanion was formed except with the less acidic oxides (As₂O₃, Sb₂O₃, SiO₂). Sulphite was partially oxidised by the carbon dioxide atmosphere to sulphate.     

Potassium meta-periodate as volumetric reagent : Iodine bromide method

Potassium meta-periodate has been used as an oxidising agent in acid medium for the volumetric estimationss of potassium iodide, arsenious oxide, antimonous oxide, stannous chloride, mercurous chloride, sodium sulphite, sodium thiosulphate, sodium tetrathionate, ferrous sulphate, potassium thiocyanate, hydrazine sulphate, phenylhydrazine hydrochloride and hydroquinone by the iodine bromide method. Carbon tetrachloride is used as an indicator. It is coloured pink during the titration. and becomes colourless at the end-point due to the formation of stable iodine bromide complex IBr2-, which does not dissociate, in the presence of a large excess of bromide ion.     

Determination of nitrite, sulphate, bromide and nitrate in human serum by ion chromatography

An ion chromatographic method has been developed for the determination of trace amounts of nitrite, sulphate, bromide and nitrate in human serum, using an ODS column dynamically coated with cetylpyridinium chloride. The anions studied were eluted with 1 mM citrate - 2.5% methanol (pH 6.5) as the mobile phase and detected by an ultraviolet detector. The interfering proteins in human serum were removed by an initial filtration through an ultrafilter-paper. The many inorganic and organic anions commonly found in serum had little effect on the determination of the four anions. Recoveries of nitrite, sulphate, bromide and nitrate in serum were 107-110, 94-106, 106-110 and 92-100%, respectively. The proposed method was also applied to human saliva and urine.     

Determination of inorganic ions in food and beverages by capillary electrophoresis

A review of the applications of electrophoresis to the determination of inorganic anions (sulphate, sulphite, phosphate, nitrate, nitrite and halides) and inorganic cations (ammonium, alkali and alkaline metals and trace elements) in food and beverages is presented.     

Preparation, characterization and application of ZnO sol containing quaternary ammonium salts

The zinc oxide sol containing quaternary ammonium salts (DMDAAC-ZnO) was synthesized by zinc acetate and dimethyldiallyl ammonium chloride via the sol–gel process. Effects of zinc acetate concentration, diethanolamine dosage and dimethyldiallyl ammonium chloride dosage on the absorbance-ratio and viscosity of the sol were investigated. Zinc oxide sols were characterized by XRD, TEM and FT-IR. DMDAAC-ZnO was applied to cotton samples and cotton samples treated were tested by antibacterial activity, UV resistance and breaking strength. The antibacterial activity and UV resistance of samples treated by zinc oxide sol containing quaternary ammonium salt were both better than sample treated by zinc oxide sol.     

Dry state preparation of radioiodine labeled meta-iodobenzylguanidine

Radioiodination of meta-iodobenzylguanidine (MIBG) by the isotopic exchange technique in the dry state has been performed. Benzoic acid, pivalic acid and acetamide have been used as molten protic media to promote isotopic exchange reactions. Ammonium sulphate, diammonium hydrogen ortho-phosphate and ammonium chloride were used as catalysts which provide acidic media to facilitate exchange reactions. Maximum radiochemical yields of 97.1±1.3% and 84.3±1.6% [¹³¹I] MIBG were obtained when ammonium sulphate and benzoic acid were used. High radiochemical yields of 88.3±1.1% and 74.4±1.5% [¹³¹I] MIBG were also obtained in case of diammonium hydrogen orthophosphate and pivalic acid which suggests their successful use as reaction media in the radioiodination of MIBG. The activation energy for the exchange reaction in ammonium sulphate was calculated to be 10.8 kcal/mole.     

Preparation of High-Purity Iron by Means of Ammonium Chloride Complexes

A method for the preparation of high-purity iron via the chlorination of a mixture containing iron(III) oxide by ammonium chloride with the subsequent decomposition of the intermediate product to iron(III) chloride, its sublimation, and further reduction in a hydrogen flow was proposed. The reaction between ammonium chloride and iron(III) oxide and the thermal decomposition of the ammonium chloride complex were thermogravimetrically studied. The conditions and energetic characteristics of these reactions were determined. The method was tested on iron-containing raw materials. The impurities in the end product of reduction by hydrogen were 0.25%.     

Particle size distribution of major inorganic species in atmospheric aerosols from Majorca (Spain)

Atmospheric aerosols collected by means of a cascade impaction system at the campus of the University of the Balearic Islands (Majorca, Spain) from November 1993 to February 1994 were analysed for chloride, nitrate, sulphate, ammonium, calcium, magnesium, sodium and potassium. Based on particle size distribution, the species studied were classified into three groups: (a) concentration decrease with particle size (sulphate and ammonium), (b) concentration increase with particle size (chloride, calcium, magnesium and sodium), and (c) independent of particle size (nitrate and potassium). A principal component analysis (PCA) revealed a clear relationship between particle size and analyte origin. Also, the origin of sulphate and potassium fine and coarse particles was found to be different.     

Anion-exchange separation of cobalt from nickel

An anion-exchange method has been developed for the separation of cobalt from nickel, based on the observation that from a malonic acid solution containing sodium nitrite, cobalt is preferentially adsorbed by the exchanger but nickel passes through. The cobalt is eluted with 2M ammonium chloride in dilute ammonia solution. Prom an ammonium malonate solution containing chloride and nitrate, cobalt is quantitatively electro-deposited on a platinum cathode to give a bright, adherent deposit. Nickel is deposited from a solution of similar composition.