摘要:

The accumulation/voltammetric behavior of the tricyclic antidepressant imipramine (Imip) was investigated at a fatty acid modified carbon paste electrode This hydrophobic drug accumulated onto the electrode surface, then was stripped by scanning the potential toward the positive direction. The oxidation peak response showed a great enhancement on using the modified electrode over the unmodified one. The peak current was examined with respect to preconcentration time, pH, paste composition, reproducibility, possible interferences and other variables. The response is linear over the range from 0.1 to 8.0 μM (r = 0.9980), after 3 minutes stirring time, using phosphate (0.1 M) pH 9. A detection limit of 0.001 μM was obtained. The method was applied to the pharmaceutical formulation Tofranil and to the biological samples.

ISSN:0003-2719    

DOI:10.1080/00032719708001707

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

For the purpose of investigation of the electroanalytical properties of Mo(VI) at a hanging mercury drop electrode (HMDE) in nitrate media, square-wave voltammetry (SWV) was used. The effect of the parameters at the excitation signal on the first SWV peak of molybdenum is discussed. It was found that the best results were obtained with the following SWV parameters: initial potential 0.000 V, final potential -1.000 V, frequency 40 Hz, amplitude 0.02 V, scan increment 2 mV and purge time 240 s.

ISSN:0003-2719    

DOI:10.1080/00032719708001708

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The colour reactions of molybdoyttric acid and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol) were investigated. Three highly sensitive spectrophotometric methods for the determination of yttrium have been developed, based on the ion-assocation complexes of molybdoyttric acid with three basic dyes (BD), e.g. rhodamine B (RB), butyl rhodamine B (BRB) and nile blue (NB) in aqueous acidic solution in the presence of poly(vinyl alcohol) (PVA). Their spectrophotometric behaviors, such as the suitable conditions for the reactions, the composition of the ion-association complexes, and the effects of foreign ions, have been studied. The absorption maxima waves were at 590, 580 and 590 nm with apparent molar absorptivities of 3.53 × 105, 4.74 × 105and 4.99 × 105L mol−1cm−1, respectively. Beer's law was obeyed up to 3.5, 3.0 and 3.5 μg yttrium per 25 ml, respectively. The detection limits (3 [sgrave] blank) were 1.8, 2.6 and 4.8 ng ml−1, respectively, and for a 0.08 μg ml−1solution of yttrium the relative standard deviations were 3.2, 2.8 and 1.1%, respectively (n = 6). The proposed methods have been applied to the spectrophotometric determination of trace amounts of yttrium in magnesium alloys and some geological samples.

ISSN:0003-2719    

DOI:10.1080/00032719708001709

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708001710

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The analysis of random errors is discussed for the equilibrium constants of very stable metal complexes, determined through competitive potentiometric methods. Prior to this analysis the calculation of standard deviations both for overall and stepwise equilibrium constants is considered. Clues are given as to how a system can be properly characterized. To illustrate the error analysis, the following systems were selected: Cu(II) andL-2,6-diaminohexanoic acid (L-lysine); Cu(II) and ethylene diaminotetraacetic acid (EDTA); and Cu(II), EDTA and 1,2-dihydroxybenzene (catechol).

ISSN:0003-2719    

DOI:10.1080/00032719708001711

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708001696

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor