‘J’HE MOST COMMONLY USED METHODS for the estimation of uric acid are those colorimetric procedures utilizing the reduction of phosphotungstic acid (1-7). Since these procedures are not specific for uric acid, an enzymatic procedure utilizing uricase, which oxidizes uric acid to allantoin, has been employed by a number of investigators (8-12). The enzymatic method, dependent upon the absorption ...

The performance of a simple colorimetric assay for urinary nicotine metabolites to assess smoking status in diabetic subjects (n = 251) was investigated. Several variations of the colorimetric assay and a qualitative extraction procedure were evaluated in comparison with a cotinine immunoassay as the "gold standard." Among these, the best overall performance was achieved with the qualitative te...

We developed a colorimetric and chromatographic assay for oseltamivir to assess the authenticity of Tamiflu (F. Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir. The colorimetric assay is quantitative and relies on an extractable colored ion-pair complex of oseltamivir with Congo red or bromochlorophenol blue. The reverse-phase chromatograph...

A simple micro (0.1 ml.) colorimetric method is described for the determination of serum calcium. This method employs the differential chelating characteristic of glyoxyl bis (2-hydroxyanil) in the presence of other divalent cations. The serum sample is placed in a colorimetric tube followed by additions of water, glyoxyl bis (2-hydroxyanil) reagent, and alkaline carbonate color developer. Chlo...

An indole-azadiene conjugate (1), synthesized by facile one-step condensation, behaves as a highly selective probe for detection of fluoride ion both in colorimetric and fluorometric analyses. The probe 1 shows F(-)-selective color change from colorless to yellow and appearance of green fluorescence. 1H NMR analysis and ab initio calculation reveal that the F(-)-induced colorimetric and fluorom...

In this paper, we propose a new method to predict the images on a CRT and a hardcopy of skin color under various illuminants. Spectral reflectance of human skin is analyzed by principal component analysis and it is shown that the spectral reflectance can be estimated by three basis functions. The estimation allows colorimetric color reproduction without colorimetric measurements for each illumi...

Since color scanners are not colorimetric, the optimal mapping from scanned values to colorimetric values is inherently nonlinear. Characterization of the scanner requires approximating this nonlinear mapping from the space of scanned values to a device independant color space. Neural networks are particularly suited to this task. Performance using an arti cial neural network generated LUT is c...

.............................................................................................................. vii Chapter 1: Introduction ......................................................................................... 1 Statement of the Problem .................................................................................. 1 Reason for Interest in the Study ..........................

In commonly used procedures for colorimetric assay of orotic acid in biological materials, certain substances interfere, positively or negatively. Some that interfere negatively are ornithine, cysteine, citrulline, tyrosine, proline, hydroxyproline, and polyamines. Protein and interfering agents are easily removed by first isolating the total organic acid fraction. The orotic acid in this fract...

A fully automated method has been developed for the determination of total cholesterol in blood serum, using the AutoAnalyzer system. According to the new method, based on the cholesterol determination of Abell et a!. (1), the serum sample is saponified and subsequently extracted with carbon tetrachloride. After treatment with Liebermann-Burchard reagent, the amount of cholesterol is determined...