A bacterium tentatively identified as a Pseudomonas sp. was isolated from a laboratory aquifer column in which toluene was degraded under denitrifying conditions. The organism mineralized toluene in pure culture in the absence of molecular oxygen. In carbon balance studies using [ring-UL-14C]toluene, more than 50% of the radioactivity was recovered as 14CO2. Nitrate and nitrous oxide served as electron acceptors for toluene mineralization. The organism was also able to degrade m-xylene, benzoate, benzaldehyde, p-cresol, p-hydroxy-benzaldehyde, p-hydroxybenzoate and cyclohexanecarboxylic acid in the absence of molecular oxygen.

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Isolation and characterization of a bacterium that mineralizes toluene in the absence of molecular oxygen.

Determination of carbon, phosphorus, nitrogen and silicon species in waters

Electrocatalytic oxidation of nitrite at an aluminum electrode modified by a chemically deposited palladium pentacyanonitrosylferrate film

A bacterium capable of utilizing fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate) as a sole carbon source was isolated from fenitrothion-treated soil. This bacterium was characterized taxonomically as being a member of the genus Burkholderia and was designated strain NF100. NF100 first hydrolyzed an organophosphate bond of fenitrothion, forming 3-methyl-4-nitrophenol, which was further metabolized to methylhydroquinone. The ability to degrade fenitrothion was found to be encoded on two plasmids, pNF1 and pNF2.

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Involvement of two plasmids in fenitrothion degradation by Burkholderia sp. strain NF100

A novel method for the spectrophotometric determination of nitrite in water.

A Rapid Spectrophotometric Method for the Determination of Nitrite in Water.

A sensitive and selective colour reaction for the determination of nitrite is presented. Nitrite reacts with p-aminophenylmercaptoacetic acid in the presence of hydrochloric acid to form a diazonium cation, which is subsequently coupled with N-(1-naphthyl)ethylenediamine dihydrochloride in acidic medium to form a stable bluish violet azo dye. The method is suitable for the determination of nitrite from 0.02 to 0.80 p.p.m. in a 1.0-cm cuvette. The observed molar absorptivity and Sandell's sensitivity of the azo dye are 4.65 × 104 l mol–1 cm–1 and 0.001 µg cm–2, respectively. The method is free from most interferences. The method has been applied to polluted water samples and the results obtained compare favourably with those from standard methods.

Spectrophotometric determination of nitrite in water

Surfactant-mediated extraction of iron and its spectrophotometric determination in rocks, minerals, soils, stream sediments and water samples

Application of a differential technique in laser-induced fluorimetry: simple and a precise method for the direct determination of uranium in mineralised rocks at the percentage level

A precise, accurate and rapid method for the sequential determination of FeO and Fe2O3 in rocks, soils and some non-refractory minerals by 1,10-phenanthroline spectrophotometry is described. Fe(II) and Fe(III) were leached from the sample (−200 mesh) using a mixture of NH4HF2 and H2SO4 at 40–80 °C for 10 min on a hot plate. Both Fe(II) and Fe(III) could be conveniently estimated sequentially from the same reaction mixture at the μg g−1 to percentage level. The method is better than the existing wet chemical methods, including the commonly used Pratt's titrimetric redox method, for Fe(II) and Fe(III) determinations in rock and soil samples in terms of precision, accuracy and rapidity. The throughput of the method was very high; at least forty to fifty samples could be estimated easily in a day. The results obtained compare favourably with those obtained by Pratt's method, as well as for certified/recommended values of a set of eleven certified reference materials having FeO and Fe2O3 contents in the range 0.21–14.63% and 0.58–8.48%, respectively. The optimised 1,10 phenanthroline method was found to be accurate to within 0.21% m/m FeO and 0.30% m/m Fe2O3 compared with the literature values of the certified reference materials studied.

P. K. Tarafder

Papers

A Rapid Spectrophotometric Method for the Determination of Nitrite in Water.

Spectrophotometric determination of nitrite in water

Surfactant-mediated extraction of iron and its spectrophotometric determination in rocks, minerals, soils, stream sediments and water samples

Application of a differential technique in laser-induced fluorimetry: simple and a precise method for the direct determination of uranium in mineralised rocks at the percentage level

An Optimised 1,10-Phenanthroline Method for the Determination of Ferrous and Ferric Oxides in Silicate Rocks, Soils and Minerals