摘要:

Two simple and sensitive spectrophotometric methods for the determination of amlodipine besylate (ADB) in pure forms and tablets are described. These methods are based on the formation of an ion association complex between the drug and an acidic dye, Bromothymol blue, which is extractable into chloroform and has an absorption maximum at 405nm (Method-A), or by the formation of an oxidative coupling product with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in the presence of ceric ammonium sulphate (absorption maximum at 630nm (Method-B)). Beer's Law limits for Methods A and B are 5 to 40 μg/ml. All variables in these methods are optimised and the reaction mechanisms are presented. No interferences were observed from tablet additives and the applicability of the methods was examined by analysing tablets containing ADB. The quantities determined were 99.5–100.2% of the expected value.

ISSN:0003-2719    

DOI:10.1080/00032719708002295

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

We developed an interfacial device to couple hydride generation with mass spectrometry. Semimetals in sample solutions were reduced to gaseous hydrides by sodium borohydride and the generated hydrides were condensed in the interface device. The evolved hydrides were introduced into a GC-MS spectrometer. Detection limits for the semimetals were 1 ng for As and Sb, and 5 ng for Ge and Sn on the basis of mass chromatograms of the respective hydrides.

ISSN:0003-2719    

DOI:10.1080/00032719708002296

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An assessment of constant current anodic stripping potentiometry on a glassy carbon gold film electrode (GCAuFE) is described for the determination of arsenic in fish and water samples. The electrolytic preconcentration of arsenic, as As0, on the gold film was affected by the tendency for increased hydrogen evolution at longer deposition times (>3 min.), as well as by the presence of organic and inorganic substances. The hydrogen evolution problem was avoided by use of short deposition time (<1 min.), while organic and inorganic interferences were overcome either by sample decomposition and/or by use of standard additions for quantification. The decomposition of sample material by dry ashing with magnesium nitrate, as an ashing aid, enabled accurate determination of arsenic in fish on the GCAuFE. Reliable determination of arsenic in water samples was also accomplished after dilution with concentrated hydrochloric acid.

ISSN:0003-2719    

DOI:10.1080/00032719708002297

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A highly selective, sensitive, rapid and economical differential pulse-polarographic (DPP) method has been developed for the quantitative determination of trace amounts of arsenic in various environmental and crude oil samples. The morpholine-4-carbodithioate of arsenic was quantitatively adsorbed on microcystalline naphthalene in the pH range of 6.0–9.5. The metal complex alongwith naphthalene was shaken with 10 ml of 1 M HCl and arsenic determined with a differential pulse polarograph using HCl-pyridine-NaCl as the supporting electrolyte. Arsenic may also be adsorbed quantitatively under similar conditions on morpholine-4-dithiocarbamate-cetyltrimethylammonium bromide-naphthalene adsorbent packed in a column at a flow rate of 0.5–5.0 ml/min and determined similarly. The detection limit is 0.016 ppm at the minimum instrumental setting (signal to noise ratio=2). Arsenic is being determined in the concentration range of 0.08–9.0 ppm with a correlation factor of 0.9996 and a relative standard deviation of ±0.81% (n=8). Various parameters such as the effect of pH, volume of aqueous phase, and interference of a number of metal ions and anions on the estimation of arsenic have been evaluated to optimise the conditions for the estimation of arsenic in various environmental and crude oil samples.

ISSN:0003-2719    

DOI:10.1080/00032719708002298

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A systematic study on the solvent extraction behaviour of quadrivalent titanium, zirconium and hafnium from salicylate media using triphenylarsine oxide as an extractant has been undertaken and reported in this manuscript. The optimum extraction conditions are evaluated from critical study of various experimental parameters. The probable composition of the extracted species is ascertained from logD-logC plots. The method is rapid, accurate and highly reproducible.

ISSN:0003-2719    

DOI:10.1080/00032719708002299

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The trapping efficiency of fourteen solid adsorbent tubes for sampling trace level of carbonyl sulfide was quantified. A thermal desorption gas chromatographic method for the accurate separation of carbonyl sulfide from other simultaneously collected reduced volatile sulfur gases was developed. Results demonstrated that Silica Gel and Carbotrap 301 were the best solid adsorbent material for trapping carbonyl sulfide if the sweep gas or the sampled atmosphere is dry. Molecular Sieve and Carbosieve SIII (along with calcium chloride in a drying tube) were the best solid adsorbent material for trapping carbonyl sulfide if the sweep gas contains moisture (i.e., normal field sampling conditions).

ISSN:0003-2719    

DOI:10.1080/00032719708002300

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708002301

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719708002284

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor