摘要:

An enrichment method is described for the determination of nickel in urine by flame atomic absorption spectrometry after preconcentration with ammonium pyrrolidine dithiocarbamate on activated carbon. The recoveries are above 90%. The factors affecting recoveries, such as pH, amounts of activated carbon and complexing reagent, and the contact times, were also studied.

ISSN:0003-2719    

DOI:10.1080/00032719608000403

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Two new spectrophotometric methods for the simultaneous determination of analgin and hyoscine N-butyl bromide in their binary mixture are described. In the first method, derivative spectrophotometry, the determination of these drugs were performed by measuring the dA/dλ values at 291.8 nm and 219.8 nm in the first derivative spectra of the mixture for analgin and hyoscine N-butyl bromide respectively. The relative standard deviation of the method was found to be 0.08% for analgin and 0.77% for hyoscine N-butyl bromide. In the second method, the determination of these compounds in mixture was realized by precipitating hyoscine N-butyl bromide with ammonium reineckate at pH 6.0 selectively and reading the absorbance of the solution of the precipitate in acetone at 532.2 nm for hyoscine N-butyl bromide and, by measuring the dA/dλ values at 306.2 nm in the first derivative spectra of the remaining solution for analgin. The relative standard deviation of the method was found to be 0.75% for hyoscine N-butyl bromide and 0.10% analgin. These two methods have been succesfully applied to a sugar-coated tablets containing hyoscine N-butyl bromide and analgin.

ISSN:0003-2719    

DOI:10.1080/00032719608000404

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A simple colorimetric procedure is described for the quantitation of ampicillin and amoxicillin in their pharmaceutical preparations. The color production is based on the reaction of the oxidation product of ascorbic acid, dehydroascorbic acid, with the corresponding penicillenic acids obtained by the degradation of the antibiotics after heating under acidic conditions. The reaction demonstrated selectivity towards the penicillins having amino acid side chains and thus allowed interference-free quantitation of ampicillin and amoxicillin in combination with cloxacillin or clavulenic acid. The procedure showed good accuracy and precision and offers advantages over the official and many other reported analytical procedures.

ISSN:0003-2719    

DOI:10.1080/00032719608000405

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Commercially available C18-solid-phase extraction(SPE) materials, representing packed bed, disc and membrane-types were evaluated for their applicability as effective tools in the sample preparation step of HPLC assays of selective drugs and their metabolites from aqueous and serum samples. Chlorzoxazone (I) and its metabolite 6-hydroxychlorzoxazone (II), phenylbutazone (III) and its metabolite oxyphenylbutazone (IV), and imipramine (V) and its metabolite desipramine (VI) were extracted using each SPE device. In aqueous samples, the highest recoveries of I were achieved with packed bed or C18 disc, whereas the best recoveries of II were achieved with the packed bed-C18. The highest recoveries of III and IV were achieved with packed bed-C18, disc and membrane C18, and the best recoveries of V and VI were achieved with SPEC disc -C18. In serum samples, the highest recoveries of I and II were achieved with packed bed or Empore disc -C18, the best recoveries of III and IV were achieved with packed bed-C18, and SPEC disc C18 and the best recoveries of V and VI were achieved with SPEC disc -C18. The packed-bed and SPEC C18 disc materials were determined to be the best overall devices based on analyte recoveries and precision data.

ISSN:0003-2719    

DOI:10.1080/00032719608000406

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A colorimetric method is proposed for the determination of etilefrine hydrochloride, prenalterol hydrochloride and ritodrine hydrochloride, and their dosage forms. The proposed method depends on nitrosation of the phenolic drugs with sodium nitrite in acidic medium with subsequent chelation by copper (II) ions resulted in the formation of stable red color copper chelate which shows a maximum absorbance at 510, 460 and 520 nm for etilefrine, prenalterol and ritodrine chelate, respectively. The experimental conditions leading to optimum color stability and intensity were studied. The proportions of the reactants and the stability constant for the copper chelates were determined. The copper chelates obey Beer's law and their absorbance were used for the determination of the three drugs in their pharmaceutical dosage forms. To confirm the validity of the proposed method, recovery studies were carried out using the standard addition method. At the same time, the results of the applications of the method to the assay of the tested drugs in their commercial preparations were compared statistically with either an official or a published method. The proposed method demonstrate high percentage of recoveries with good accuracy and precision.

ISSN:0003-2719    

DOI:10.1080/00032719608000407

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The determination of paracetamol and salicylamide in the presence of each other was performed by means of a first-derivative spectrofluorimetric method with a “zero-crossing” technique of measurement. The reported method is based on the oxidation of the paracetamol with potassium hexacyanoferrate (III) to give a fluorescent substance.

ISSN:0003-2719    

DOI:10.1080/00032719608000408

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A complexation chemistry model is applied for the study of chelating ion exchange systems. A method is presented for the determination of equilibrium constants of the metal chelates with the chelating resin Dowex A-1. It is based on simultaneous pM and pH measurements in optimal pH ranges using ion selective electrodes. Equilibrium constants were determined for 1:1 calcium(II), copper(II), lead(II) and mercury(II) chelates with the resin. Theoretical distribution coefficients were calculated as function of pH for respective metal ion resin systems from the equilibrium constants determined.

ISSN:0003-2719    

DOI:10.1080/00032719608000409

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A procedure for simultaneous determination of chromium, nickel and selenium in their model mixtures, using adsorption stripping voltammetry (AdSV) for chromium and nickel and cathodic stripping voltammetry (CSV) for selenium is proposed. The effect of the adsorption time, pH, presence of possibly interfering anions, molar ratio of Cr, Ni and Se and the order of their determination in solution on the sensitivity peaks was examined. By a suitable choice of all these parameters, a simultaneous determination of the mentioned elements by voltammetric techniques in model mixtures was achieved.

ISSN:0003-2719    

DOI:10.1080/00032719608000410

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A solvent-soluble membrane filter is proposed for a simple and rapid preconcentration and spectrophotometric determination of iron (II), which was collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of iron (II)-1,10-phenanthroline with an anionic surfactant of dodecyl sulfate. The ion-associate collected was dissolved in 5 ml of 2-methoxyethanol together with the filter. The color intensity due to the ion-associate in the resulting solution was measured at 510 nm against a reagent blank. Beer's law is obeyed in the range 1–15 μg Fe (II) in 5 ml of solvent with excellent reproducibility, and detection limits better than 0.5 μg dm−3as Fe (II) can be achieved. The diverse components normally present in water do not interfere when proper masking reagent is added. The proposed method has been applied to the analysis of water samples from several sources such as river water, ground water and tapwater samples, the recoveries of the iron (II) added to the samples are quantitative, and results found are satisfactory.

ISSN:0003-2719    

DOI:10.1080/00032719608000411

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new decomposition set which digests nine samples at the same time was developed. Chromium, copper and nickel amounts were analyzed in water hyacinth (Eichhornia crassipes) samples by atomic absorption spectroscopy using only nitric acid or a combination of sulfuric and nitric acid. The results were statistically compared by t- and F- tests. Since there was no significant difference between these two methods, only nitric acid may be used for decomposition of plant samples.

ISSN:0003-2719    

DOI:10.1080/00032719608000412

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor