HEN ALCOHOLIC POTASSIUM HYDROXIDE and m-dinitrobenzene are used in the Zimmerman reaction (1) for the determination of 17ketosteroids (17-KS), a purple complex is formed which has a broad absorption band in the green portion of the visible spectrum. Application of this reaction to urine extracts also gives rise to other chromogens which are brown in color. On occasion, the ratio of brown chromo...

A simple, specific and reproducible serum iron method is described using the recently synthesized and highly sensitive chromogen, tripyridyl-S-triazine. The absorbance of this chromogen is compared to other iron reagents. Procedural modifications are given for using the Ramsay iron-binding capacity method with this serum iron procedure. The normal values found agree with most of those in the li...

In this automated single-run enzymatic procedure for specific determination of triglycerides in serum, free glycerol is removed from the reaction mixture by pre-incubation with glycerol phosphate oxidase and peroxidase. The subsequent addition of lipase and the chromogen, 4-aminoantipyrine, results in the formation of color proportional to the amount of triglycerides in serum. Standards contain...

The recovery of five free ketosteroids, three glucuronides, and six sulfates, added to water or urine and subjected to acid hydrolysis for various lengths of time, was investigated. Dehydroepiandrosterone (DHEA) in all its forms was most susceptible to destruction. The behavior of glucuronides and sulfates differed, and no single set of conditions provided equal recovery for all conjugates. A c...

New, simple and cost effective spectrophotometric methods have been developed for the quality assessment of isoniazid (INH), in bulk and in pharmaceutical formulations by using novel reagents. The proposed methods involve the utility of ethyl 2-[(E)-(4hydroxyphenyl) diazenyl]-3-oxobutanoate and benzil as novel reagents for the determination of INH. Developed methods are based on the condensatio...

The concentration of plant pigments in excreta vs. food provided a measure of digestibility of most plants by grasshoppers. Digestibility values obtained with the chromogen-ratio method and consumption-excretion ratios were highly correlated (r = 0.789**). Greatly disparate results were obtained in 4 cases. The chromogen method, when applicable, gave better duplicability and eliminated many of ...

An automated micromethod for measuring iron concentration in serum employing thioglycollic acid and bathophenantroline sulphonate as reducing agent and chromogen respectively, is described. Measurements are carried out using an AutoAnalyzer (Technicon) and require 0.1 ml of sample. The reproducibility, assessed by the mean coefficient of variation (1.9%), and the mean recovery of iron added to ...

Two simple, sensitive, accurate, rapid, and economical spectrophotometric methods have been developed for the estimation of diacerein in Pharmaceutical dosage forms. Method A is based on the reaction of diacerein with Folin-Ciocalteu reagent, in the presence of 0.5 N sodium hydroxide solution, giving a pink-colored chromogen, which shows maximum absorbance at 512 nm against reagent blank, while...

After a preliminary hydrolysis of the serum samples, the liberated sialic acid is determined by the thiobarbituric acid method of WARREN adapted to the Autoanalyzer. By measuring the developed chromogen in very hot solution, the use of extraction or the addition of stabilizing agents is avoided. Sixty determinations can be run per hour and the optical densities follow a straight line well withi...

A method for the determination of total cholesterol in serum is described. Optimum conditions are found for the isolation of the steroid free from extraneous chromogens, and a new sensitive colour reagent is introduced. The procedure is convenient for routine application, the final colour being light-stable and reasonably time-stable at room temperature. Comparisons are made with one other meth...