The chemical nature of the important new chromogen ABTS [2,2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid)] is described together with an account of the redox and spectroscopic properties of the system ABTS--H2O2--peroxidase. Keq. is calculated and a study of the steady-state kinetics over a whole range of substrate concentrations is reported. By using novel methods of kinetic analysis, a...

Three simple and sensitive visible spectrophotometric methods (A, B, and C) have been developed for the quantitative estimation of mesalamine in bulk drug and pharmaceutical dosage forms. Methods were based on the formation of colored chromogens, which were measured at 552 nm, 440 nm, and 494 nm, respectively. The results obtained with the proposed methods were found to be unsatisfactory with t...

A simple accurate and reproducible spectrophotometric method was established for the estimation of Cilastazol based on the formation of condensation product. The method is based on the formation of yellow colored chromogen, when the drug reacts with p-Dimethylaminobenzaldehyde (PDAB). The colored species has an absorption maximum at 425 nm and obeys Beer's law in the concentration range of 6-10...

HAAS and HILL [1925, 1] have recently directed attention to a chromogen of considerable interest which escapes from the plasmolysed cells of Mercurialis perennis. If the coarsely divided tissue be steeped, anaerobically, in chloroform water for a short time, there results an extract which, on exposure to oxygen, assumes first a rich blue and then a yellow-brown colour. These investigators [1925...

A number of chromogens have been proposed in the past. In the glucose oxidase “GOD-Perid”1 method, the subject of study in this paper, ABTS is used as the chromogen (6). Unfortunately, the glucose oxmdase methods are not free of interference from other substances, uric acid being one. Here, I examine each reaction step of the GOD-Perid method, discuss possible mechanisms of interference by uric...

Chalcones are open analogues of flavonoids and give bright red to purple colours with different reagents which can be used to distinguish them from other flavonoids such as flavanones, flavones, aurones etc. Studies show that the bathochromic shift arises due to the formation of carbonium ion at the carbonyl group (>C = O) of the chromogen (ArCOCH = CHAr) as an intermediate which produces deepe...

Manual and automated methods for the determination of blood glucose have been devised using an oxidase/peroxidase system, with dl adrenaline, a non-carcinogen, as oxygen acceptor. The manual technique employs a stable single solution protein precipitant and the other reagents used are also stable. The automated methods are operated at 40/hr sample speed and washover between samples, over a very...