A simple, sensitive and economical spectrophotometric method was developed for the determination of cefixime trihydrate in pharmaceutical formulations. This method is based on the formation of pink colored chromogen complex by the reaction of drug with ferric chloride and 2, 2 bipyridyl, which absorbs maximally at 520 nm. Beer’s law is obeyed at a concentration range of 110 mcg/ml for method. T...

The original Ellman's spectrophotometrical method for cholinesterase activity determination uses 5,5'-dithiobis-2-nitrobenzoic acid (DTNB, Ellman's reagent) as a chromogen and records the level of cholinesterase activity as an increase of absorbance at 412 nm. Although this procedure usually poses no problem, exceptions arise when the concentration of DTNB is far higher than the concentration o...

We describe a colorimetric assay for glucose determination in human serum, with use of the chromogen 2-amino-4-hydroxybenzenesulfonic acid (AHBS), glucose oxidase, and peroxidase. With this assay, glucose concentrations less than or equal to 27.8 mmol/L can be measured in serum, with a sample/reagent volume ratio as low as 0.0025. The chromogen itself is easily soluble in water and does not req...

Simple and rapid spectrophotometric & chromatographic methods have been developed and validated for the determination of Darunavir and Ropivacain in tablets and as bulk drug. The methods applied were involing use 1,2-naphthoquinone-4-sulphonate (NQS). The formar was solubilised in an alkaline medium with NQS to form an orange-colored product with λmax at 488 nm while the later gave blue colored...

The use of bilirubin oxidase to remove interference by bilirubin in hydrogen peroxide/peroxidase detecting systems is hampered by its inherent "chromogen oxidase" activity (its ability to oxidize the chromogens used in the systems). This unwanted activity is greater than 99% inhibited by 0.5 mmol/L cyanide, 97% inhibited by 20 mmol/L azide. At these same concentrations, they inhibit bilirubin o...

Four different, well known colour reagents for iron determination were tested in a citrate buffer at pH 2.0 under the same automated standard conditions and compared with a manual reference method on human serum and plasma samples. Specific results were obtained only with the chromogen tripyridyl-s-triazine. A micromethod was developed, which is generally well suited for automated, direct serum...

A new chromogen that absorbs maximally at 329nm was frequently found in the liver oils of the freshwater fish Bagarius bagarius and Wallago attu. It was shown to be a diester of 3-hydroxyretinol. 3-Hydroxyretinol was found to be a metabolite of lutein during the biosynthesis of 3-dehydroretinol in a freshwater fish. A new method for the chemical synthesis of 3-hydroxyretinol from methyl 3-dehyd...