A new method for the determination of nitrogen in biologic material is described. It is basedon an improvedashingprocedureand the Berthelot reactton in which nitrogen is converted to indophenol.The concentration of this substance is determined photometrically. The proposedmethod yields the same results as the Keldahi procedure; however, it offers a higher degree of sensitivity combined with the...

The objective of the present work was to compare colorimetric and distillationÈtitration methods to determine the ammonia-nitrogen con3 centration in sheep and goat urine samples. Colorimetric methods used were based on the indophenol reaction, whereas titrimetric methods were based on the alkali distillation of ammonia from the urine and its titrimetric determination with a standard acid. Colo...

This paper is a continuation of the study of the penetration of oxidation-reduction indicators into living plants of Valonia ventricosa. Two indicators have been used, namely, meta-bromo-phenol indophenol and guaiacol indophenol. The first one is the most positive of any of the indicators so far used in this series and is very readily reduced by living cells. The second one is in the region of ...

A simple, developed, fast and accurate spectrophotometric method for determination of Mesalazine (MSL) in its pure form pharmaceutical preparation (Pentasa). This was based on the formation complex between MSL reagent 2,6-Dichloro indophenol sodium (DIS) to give a red color product that gives ats highest absorption at wavelength 520 nm. The best conditions were found (time, temperature, optimal...

HARRIS [1933] concluded from the results of biological tests that only about one-third of the material in Jensen rat sarcoma which reduces 2:6-dichlorophenolindophenol is ascorbic acid. Later Young & Mitolo [1934] and Mitolo [1934] brought forward evidence which they believed to indicate that brain tissue also contains an indophenol-reducing factor (I.F.) which is not ascorbic acid. Recent inve...

Despite the wide application of nanoscale zero valent iron (nZVI) for the treatment of a plethora of pollutants through reductive reactions, reactivity evaluation of nZVI towards dehalogenation has not been standardized. In this light, it was desired to develop a simple colorimetric assay, for versatile laboratory application, using merely a spectrophotometer for color intensity determination. ...

From stroma-freed chloroplasts of Antirrhinum m ajus polypeptides with the apparent molecular weights 44 000, 26 000 and 20 000 were isolated. The antiserum to a polypeptide with the moleculair weight 44 000 inhibits the photoreduction of anthraquinone-2-sulfonate with dichlorophenol indophenol/ascorbate when the concentration of the electron donor dichlorophenol indophenol is low. The antiseru...