A. L. J. Rao

Spectrophotometric Methods for the Determination of Fluoroquinolones: A Review

The majority of quinolones of clinical use belong to the subset of fluoroquinolones, which have a fluoro group attached the central ring system, typically at the 6-position. Fluoroquinolones are widely used in human and veterinary medicine. In recent times there has been significant development in the field of fluoroquinolones and many new analogues have been synthesized. The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control and pharmacodynamic and pharmacokinetic studies. In this review article, various spectrophotometric methods used for determination of fluoroquinolones have been covered. The methods include visible spectrophotometry, which is based on formation of ion-pair or charge transfer complexes, UV spectrophotometry and derivative spectrophotometry. The application of these methods for the determination of fluoroquinolones in pharmaceutical and real samples has also been discussed.

Spectrophotometric determination of osmium with 1-phenyl-4,4,6-trimethyl-(1H,4H)-2-pyrimidinethiol and extraction into molten naphthalene

Conditions have been developed for the spectrophotometric determination of osmium with 1-phenyl-4,4,6-trimethyl-(1H,4H)-2-pyrimidinethiol after extraction of the complex into molten naphthalene. Beers law holds for the concentration range of 4-77 mug of osmium in 10 ml of the final solution. The molar absorptivity is 1.33 x 10(4) l.mole(-1).cm(-1). The reagent is highly selective for osmium.

SPECTROPHOTOMETRIC DETERMINATION OF ZIRAM, FERBAM AND ZINEB WITH DIPHENYLCARBAZONE

A procedure has been developed for the determination of ziram (zinc dimethyldithiocarbamate), ferbam (ferric dimethyldithiocarbamate) and zineb (zinc ethylenebisdithiocarbamate) after their decomposition and extraction of the diphenylcarbazone complexes of the zinc or iron into isobutyl methyl ketone. These complexes absorb strongly at 520 nm. The method is rapid, sensitive and selective and can be used for the determination of these dithiocarbamates in commercial and synthetic mixtures.

Spectrophotometric determination of zinc bis-ethylenedithiocarbamate (zineb)

A spectrophotometric method has been developed for the determination of zineb by converting it into a molybdenum ethylenedithiocarbamate complex, which is then extracted into isobutyl methyl ketone and measured at 670 nm against a reagent blank. Beers law is obeyed over the zineb concentration range 2-40 mug/ml in the extract. The method is sensitive and can be used for determination of zineb in the presence of ziram, thiram or ferbam.

Spectrophotometric determination of iron(III) dimethyldithiocarbamate (ferbam).

A spectrophotometric method was developed for the determination of ferbam (iron(III) dimethyldithiocarbamate) by converting it into an iron-phenanthroline complex, which was then absorbed on microcystalline naphthalene in the presence of tetraphenylborate, and the absorbance was measured at 515 nm against a reagent blank. The molar absorptivity of the complex was 1.2 x 10(4)l mol(-1)cm(-1). Ten replicate analyses of a sample solution containing 150 mug of ferbam gave a relative standard deviation of 0.84%. Beers law was obeyed over the concentration range 22.4-372.9 mug of ferbam. The effects of various factors such as reagent concentration and naphthalene, shaking time and diverse ions were studied in detail. The method is sensitive and selective and can be applied to the direct determination of ferbam in commercial samples and in mixtures containing various other dithiocarbamates (e.g. ziram, zineb and maneb) in foodstuffs.

Spectrophotometric Determination of Ferbam Using Sodium Selenite

Abstract A procedure has been developed for the microdetermination of ferbam (ferric dimethyldithiocarbamate) after extraction of its selenium dimethyldithiocarbamate complex into chloroform. The maximum absorbance is at 430 nm; Beers law is obeyed over the ferbam concentration range of 1.0–28.0 μg ml−1 in the extract. The method is sensitive, selective and can be safely employed for the determination of ferbam in commercial samples, and synthetic mixtures containing nabam, zineb and maneb.

Simple and sensitive method for determination of tetramethylthiuram disulphide (thiram)

A rapid, simple, direct and sensitive method has been developed for the determination of thiram (tetramethylthiuram disulphide) based on the formation of copper dimethyldithiocarbamate complex, which is rendered water-soluble by a cationic surfactant, cetytrimethylammonium bromide (CTAB). The method has been applied to the determination of thiram in synthetic mixtures, grain (wheat) samples and vegetables.

Development of a derivative spectrophotometric method for the determination of fungicide zinc ethylenebisdithiocarbamate using sodium molybdate

Neste trabalho foi desenvolvido um procedimento espectrofotometrico derivativo para a determinacao de etilenobisditiocarbamato de zinco(II), Zineb, com base na formacao do complexo azul de molibdato de sodio em meio acido. A lei de Beer e obedecida ate 40 µg mL-1 de Zineb no comprimento de onda de 956 nm. O limite de deteccao foi de 0,006 µg mL-1 de Zineb para a razao S/N = 3 considerando diversos parâmetros como o efeito da concentracao de acido. A interferencia de diversos ions na determinacao de Zineb foi avaliada. A maioria dos metais alcalinos e sais metalicos nao causou interferencias. O procedimento tem boa sensibilidade e foi empregado para a determinacao de Zineb em amostras comerciais de alimentos contendo Dithane Z 78 e Hexathane 75% W.P.. Os resultados foram comparados com procedimentos previamente propostos. Zineb foi determinado com sucesso sem a ocorrencia de interferencias na presenca de outros ditiocarbamatos, tais como Ziram, Thiram, Ferbam etc.

Extraction spectrophotometric determination of maneb with 1-(2′-pyridylazo)-2-naphthol (PAN)

A rapid, sensitive, simple and selective spectrophotometric method has been developed for the determination of micro-quantities of maneb (manganese ethylenebisdithiocarbamate) after extraction of the manganese-PAN complex in isobutyl methyl ketone (MIBK). The complex absorbs strongly at 550 nm. Beers law is obeyed over the concentration range 0.37-3.75 microg/ml. The molar absorptivity was found to be 4.1 x 10(4) l. mole(-1) . cm(-1). The developed method has been applied to the determination of maneb in commercial formulations, synthetic mixtures, grain and in the presence of various other dithiocarbamates.

Simple and sensitive spectrophotometric determination of ziram, zineb and ferbam in commercial samples and foodstuffs using phenylfluorone.

A procedure has been developed for the determination of ziram, zineb and ferbam dithiocarbamate pesticides by converting ziram and zineb into a zinc-phenylfluorone complex and ferbam into an iron phenylfluorone complex, which are then dissolved in water in the presence of cetylpyridinium bromide and pyridine as a surfactant. The method is sensitive, highly selective and can be used for the determination of ziram, zineb and ferbam in commercial samples and in foodstuffs.