Solid mineral fuels. Determination of extractable metals in dilute hydrochloric acid

2008 ◽  
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Extractable Metals

scholarly journals The spectrophotometric determination of boron in tourmalines

2005 ◽  
Vol 70 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Ljiljana Jaksic
Keyword(s):  
Hydrochloric Acid ◽  
Magnetic Separation ◽  
Relative Error ◽  
Spectrophotometric Determination ◽  
Dilute Hydrochloric Acid ◽  
Anhydrous Sodium Carbonate ◽  
Ph Adjustment ◽  
Coloured Complex ◽  
Heavy Liquids

A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA - NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.

Liquid Chromatographic Determination of Identity, Content, and Content Uniformity of Desipramine, Fluphenazine, and Promazine

1986 ◽  
Vol 69 (1) ◽  
pp. 178-179 ◽  
Author(s):  
Normand Beaulieu ◽  
Charles Gagné ◽  
Edward G Lovering
Keyword(s):  
Hydrochloric Acid ◽  
Active Ingredient ◽  
Dilute Hydrochloric Acid ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Content Uniformity ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic procedure has been developed for the assay, content uniformity, and identification of single active ingredient formulations of desipramine, fluphenazine, and promazine. The drugs are extracted from formulations with methanol or dilute hydrochloric acid and quantitated against an internal standard (norephedrine). The drugs are identified by comparison of retention times with those of the reference standards.

THE DETERMINATION OF SULPHUR IN WOOL

1937 ◽  
Vol 15b (2) ◽  
pp. 65-74 ◽  
Author(s):  
P. Larose ◽  
A. S. Tweedie
Keyword(s):  
Hydrochloric Acid ◽  
Organic Compounds ◽  
Dilute Hydrochloric Acid ◽  
Dry Weight ◽  
New Method ◽  
Macro Scale ◽  
Wool Wax

A modification of Pregl's micromethod for the determination of sulphur in organic compounds has been found to be satisfactory and convenient when applied on a macro scale to wool.The investigation of various methods of cleaning the samples shows that the best results are obtained when the wool wax is extracted with a solvent before washing with water. It is shown that a treatment with dilute hydrochloric acid is not necessary in preparing the sample.Three different procedures have been followed in determining the dry weight of the sample and the differences in the results are discussed. Results obtained by the new method are compared with those obtained by other recognized methods, and the agreement with the results of the Benedict-Denis-Barritt method is shown to be very good.

scholarly journals Spectrophotometric Method for the Determination of Some Drugs Using Fast Red B Salt

2008 ◽  
Vol 5 (s2) ◽  
pp. 1087-1097 ◽  
Author(s):  
Afaf Abul Khier ◽  
Magda M. Elhenawee ◽  
Manal S. Elmasry
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Nitro Group ◽  
Spectrophotometric Method ◽  
Dilute Hydrochloric Acid ◽  
Pharmaceutical Formulations ◽  
Zinc Powder ◽  
Fast Red ◽  
Phenolic Group

A simple spectrophorometric method for the determination of secnidazole, niclosamide, nifuroxazide and sulphasalzine is described. The method is based on reduction of the nitro group present in secnidazole and niclosamide molecule using zinc powder and dilute hydrochloric acid followed by reaction with fast red B salt in presence of ammonium chloride and sodium hydroxide, while in case of nifuroxazide and sulphasalazine the reaction takes place directly without any prior reduction between the phenolic group present in each drug and fast red B salt in presence of sodium hydroxide. Beer's law is valid in the concentration ranges 2.5-15, 1.25-10, 2.5-15, and 2.5-13.75 μg.mL-1for secnidazole, niclosamide, nifuroxazide and sulphasalazine respectively. The proposed method is applied successfully for the estimation of the mentioned drugs either in pure form or in their pharmaceutical formulations.

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

1979 ◽  
Vol 44 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Vladimír Macháček ◽  
Said A. El-bahai ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Base Catalysis ◽  
General Base ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

Synthesis of the semi-rigid analogues of prothiadene and dithiadene as potential antidepressant and antihistamine agents: 11-[2-(Dimethylaminomethyl)cyclohexylidene]-6,11-dihydrodibenzo[b,e]thiepins and 4-[2-(dimethylaminomethyl)cyclohexylidene]-4,9-dihydrothieno-[2,3-c]-2-benzothiepins

1985 ◽  
Vol 50 (5) ◽  
pp. 1078-1088 ◽  
Author(s):  
Zdeněk Polívka ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
Jan Metyš ◽  
Miroslav Protiva
Keyword(s):  
Hydrochloric Acid ◽  
Ir Spectrum ◽  
Title Compound ◽  
Dilute Hydrochloric Acid ◽  
Amino Alcohols ◽  
Geometric Isomers ◽  
Pharmacological Testing

Reaction of dibenzo[b,e]thiepin-11(6H)-one with 2-(dimethylaminomethyl)cyclohexylmagnesium chloride gave a mixture of stereoisomeric amino alcohols IX from which four homogeneous bases (IXa to IXd) were separated by chromatography. Dehydration of these compounds with boiling dilute hydrochloric acid afforded mixtures of racemic geometric isomers of the title compound VII, which were separated by crystallization. To the prevailing less polar base VIIa (E)-configuration was assigned on the basis of the IR spectrum. Using a similar procedure, thieno[2,3-c]-2-benzothiepin-4(9H)-one gave mixture of amino alcohols X from which three homogeneous stereoisomers X-A to X-C were isolated. Their dehydration resulted in both expected racemic geometric isomers VIII-A and VIII-B. Pharmacological testing proved the character of an antidepressant for the semi-rigid analogue of dithiadene VIII.

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