Spectropolarimetric Assay of R(-)-Epinephrine

Abstract

A rapid, simple and specific procedure for the simultaneous assay and determination of enantiomeric purity of pharmaceutical grade 1-epinephrine solution is described. The procedure is faster, more precise and more specific for the levoisomer than the U.S.P. XXI method. It can also be used for 1-epine-phrine inhalation solution and 1-epinephrine injection solution.     

A Simple Method for Synthesis of Methylene Dioximes Using Poly(ethylene glycol)‐400 as a Phase Transfer Catalyst

Abstract

A simple method for synthesis of methylene dioximes by reaction of ketoximes with dichloromethane in the presence of aqueous sodium hydroxide solution using poly (ethylene glycol)‐400 (PEG‐400) as a phase transfer catalyst is described.     

A Fluorescence Quenching Method for the Determination of Chromium(VI) with L-Tyrosine

Abstract

A fluorescence quenching method for the determination of Cr(VI) in aqueous solution is described. The fluorescence intensity of the system is linear ever the range 5×10^?6 - 1.0×10^?4 M Cr(VI). The method has been applied to the determination of Cr(VI) In cast iron and waste water.     

Differential Titration Based on Transient ISE Response

Abstract

A new way of evaluating potentiometric titrations based on the transient response of some ISE's is described. The method is illustrated using the titra 2+ tion of sulphate with a Ba solution using a Na-ISE in weakly mineralized waters.     

The Analytical Applications of Organic Reagents in Hydrophobic Gel Media

Abstract

The use of hydrophobic gel particles containing an organic solvent solution of chelating agents is described. With the use of a column of such gel particles, it is possible to trap or concentrate metal ions selectively on the gel particles from very dilute aqueous solution. A method for the semi-quantitative determination of trace amount of metal ions is proposed.     

Determination of Total Sulphur in Vegetation by a Turbidimetric Method Following An Oxygen-Flask Combustion

Abstract

A rapid method of determining total sulphur in vegetation is described. The plant material is combusted in an oxygen-flask, and the sulphate content of an aliquot of the absorbing solution is determined turbidimetrically as barium sulphate. The method is convenient and accurate. Its results agree closely with those obtained by the AOAC magnesium nitrate procedure.     

The Binding of Cu(II) and Zn(II) Ions by Heparin

Abstract

A method is described for measuring the ion binding capacity of heparin. The method is based on the separation of the zinc or copper complex of heparin by gel permeation. It was found that the number of the cation per average molecule of heparin depends on the pH and on the initial concentration of metal cation in solution. The absorption spectrum of heparin-Cu complex is described. The molar absorptivity of this complex is determined, as is the complex formation constant.     

Trace Analysis by ESCA-Electrochemical Measurements

Abstract

A procedure which combines electrochemical deposition and ESCA measurements for the determination of trace levels of metals in solution is described. The method is demonstrated by an experiment in which microgram quantities of Pb, Cd, and Bi are deposited on a mercury-coated platinum electrode and then detected by ESCA measurements.     

Application of the Iodide Ion-Selective Electrode in the Potentiometric Determination of Chloral Hydrate

Abstract

A simple and sensitive micro method for chloral hydrate determination based on oxidation with iodine in chloroform solution is described. The produced iodide ion in the extract is determined using the iodide ion-selective electrode by either a direct measurement, standard addition technique or potentiometric titration with standard silver nitrate solution. Samples containing 0.1 - 4.0 mg chloral hydrate are analyzed with an average recovery of 99-9% and standard deviation of 0.1%.     

Extraction and Flameless AAS Determination of Germanium in Lignite Fly Ash

Abstract

The use of dicyclohexyl-18-crown-6 methyl isobutyl ketone solution in extraction and flamelessatomic absorption spectrophotometry (AAS) determination of germanium in lignite fly ashes have been studied.

Germanium is usually determined in lignites after the carbonaceous part of the sample has been burnt by a dry or wet ashing method. However, methods are described for direct determination of germanium.

In the present paper a wet ashing method is reported for the determination of germanium in lignite fly ashes by flameless AAS after extraction into dicyclohexyl-18-crown-6 methyl isobutyl ketone (MIBK) solution. Solvent extraction is a known hydrometallurgical method that could be applied in germanium recovery.     

Spectrophotomhtric Determination of Vanadium with Salicylic Acid in Formic Acid Medium

Abstract

A method is described for the spectrophotometric determination of vanadium by measuring its colored complex with salicylic acid in formic acid medium. Lambert-Beer's law is followed in the range of 2.0 - 32.0 μg V/ml of the final solution. Thirty-six ions were tested and did not interfore, at the established conditions.     

Fluorescent Labeling of Fatty Acids with 9-Anthryldiazomethane (ADAM) for High Performance Liquid Chromatography

Abstract

A novel method for rapid and simple fluorescent labeling of carboxylic acids with 9-anthryldiazomethane (ADAM) for HPLC is described. This reagent is stable in solution and highly reactive with carboxylic acids. Esterification proceeds at room temperature without catalyst. The labeled compounds are separated using a reversed-phase system and determined with a flow-through flurometer. Picomole level of fatty acids are determined by this method.     

Selective Determination of Organic and Inorganic Thiocyanates in Aqueous Solution by IR Spectrophotometry

Abstract

A new spectrophotometric method for the determination in aqueous solution of both organic and inorganic thiocyanates is described. Organic thiocyanates are determined by measuring at wavenumber of 2150 cm^?1 the absorption of solutions directly extracted with carbon tetrachloride. Inorganic thiocyanates require a previous derivatization reaction with dimethylsulfate, and are determined as methylthiocyanates. The method is quick, accurate and selective. The results obtained suggest its utilization in analysis of aqueous samples.     

Spectrophotometic Determination of Pyrene,Fluoranthrene and Phenanthrene in Anthracene Oil

Abstract

A method for the determination of pyrene, fluoranthrene and phenanthrene in the “anthracene oil” residue, after removal of anthracene, is described utilizing measurements of absorbance at three wavelengths in the ultraviolet and solution of the three simultaneous equations produced. Molar absorptivities for the three hydrocarbons are given and the accuracy of the determination is discussed.     

Zum aminkatalysierten Abbau von Oligochlorsilan mit HCl

Tetrakis(trichlorosilyl)silan (neo-Si₅Cl₁₂) is cleaved in an amine catalysed reaction by HCl in benzene solution to tris(trichlorosilyl)silan HSi(SiCl₃)₃ (1). The amine catalysed cleavage of1 with different amines and solvents is investigated. A new method for preparation of pentachlorodisilane HSi₂Cl₅ is described and a reaction mechanism for the cleavage is postulated.

     

Indirect Microdetermination of Hydroxide Ions by Atomic Absorption Spectrophotometry

Abstract

A simple indirect atomic absorption spectrophotometric method is described for the determination of hydroxide ions. The method is based on the reduction of silver ions which takes place when hydroxide sample is treated with silver (I) solution in presence of manganese(II) ions. The unconsumed silver is determined by atomic absorption spectrophotometry. The effects of a number of factors have been studied and the method was employed for the determination of free alkali in paper samples.     

The Analysis of Fluoride in the Acetic Acid Leach Solution of Fluorspar with an Ion-Selective Electrode

Abstract

An analytical procedure for the determination of fluoride ion left in the acetic acid leach solution of the U. S. Customs method for fluorspar is presented. The technique described employs an Orion fluoride ion-selective electrode. A semilogarithmic plot of fluoride ion concentration versus millivolt response yields a linear calibration curve. The new procedure s shown to compare favorably with the Customs method in economy analysis time, accuracy and precision.     

Botanical Source Differentiation of Podophyllum Resin by HPLC

Abstract

A high-performance liquid chromatographic method to determine botanical sources of Podophyllum resin via approximate podophyllotoxin content is described. North American resin contains about 10% podophyllotoxin, the Indian variety about 40%. Samples are dissolved in mobile phase solution and analyzed by HPLC using normal-phase chromatography with detection at 280 nm. Estimates of podophyllotoxin content were made using commercially available references.     

Determination of Rhein Anthrone in Caecal Content of Rats Using Reversed Phase HPLC

Abstract

A sensitive spectrofluorimetric method is described to determine small quantities of rhein anthrone in complex biological systems as caecum content and faeces. The method is based on the stability and fluorescent properties of anthrone molecules in borax solution and combines the sensitivity of spectrofluorimetric methods with the resolution power of liquid chromatography.

After extraction of the faeces with a solution of sodium tetraborate and ascorbic acid in water and centrifugation, an aliquot of the supernatant is injected on a Sephadex-G25 precolumn. After rejection of the first fractions (fluorophors present in caecal content), rhein anthrone is collected on an RP-C18 column and eluted with an acetonitrile-borax buffer gradient. The anthrone is quantified using a fluorescence HPLC monitor.     

Analysis of Indenolol In Biological Fluids By High Performance Liquid Chromatography

Abstract

The analysis of indenolol in plasma and urine is described. The method involves extraction of the drug from plasma or urine using chloroform at basic pH. The separation was performed on CN column using methanol and 0.01M potassium dihydrogen phosphate solution 50:50. The efficiency of extraction was 97%. Minimum detectable amount by fluorescence was 20 ng/ml.