During the many years that tungstic acid has been employed as a precipitant for blood proteins, as suggested by Folin and Wu, the method has met with practically no criticism and has probably been one of the most widely employed processes used in biochemistry. It is, however, well to have more than a single method of procedure available in connection with special problems which may arise, so we...

Uric acid added to serum is incompletely recovered in tungstic acid filtrates of serum. Contrary to previous views, the poor recovery is not the result of the adsorption of uric acid upon the precipitated protein, nor is it the result of the presence in the filtrates of inhibitors of the color-forming reaction between the sodium carbonate and phosphotungstic acid reagents, and the uric acid. Ev...

Silica tungstic acid (STA) has been found to be an efficient and reusable solid acid catalyst for the synthesis of 2-amino-4H-chromenes via the three-component reaction of aromatic aldehydes, malononitrile, and β-naphthol. STA as a novel solid acid was characterized by X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy.

Ultramicro methods for the determination of serum urea nitrogen, uric acid, and creatinine have been evaluated and the results are re corded in reports VII, VIII, and IX, respectively. The method for the determination of urea nitrogen is an ultramicro adaptation of the reaction in which a blue color is developed when the ammonium ion reacts with phenol and hypochlorite. Ammonia is released from...

NCOMPLETE RECOVERIES OF CREATININE added to plasma or serum have been reported by investigators who have used a tungstic acid protein precipitation and the picric acid method of analysis (1-7). Controversy exists as to whether the creatinine is lost by adsorption on the protein precipitate or whether the alkaline picrate formed in these circumstances is modified so that less color is formed. Ow...