Deproteinization is a necessary step in many procedures for the chemical analysis of body fluids. A variety of reagents have been used for this purpose, especially in blood analysis. Of these perhaps tungstic acid and trichloracetic acid are the most widely used to-day, and for this reason we may consider them a moment. Folin and Wu (1919) introduced tungstic acid to prepare proteinfree filtrat...

The studies to be reported were undertaken with the idea of throwing more light on the proteins of the gastric juice. It has been found that they can be precipitated by tungstic acid at pH 3.5 and that, although heating coagulated a protein, there remained in solution a heat-uncoagulable substance which gave a positive biuret reaction. Interest in the subject was stimulated by the investigation...

The studies to be reported were undertaken with the idea of throwing more light on the proteins of the gastric juice. It has been found that they can be precipitated by tungstic acid at pH 3.5 and that, although heating coagulated a protein, there remained in solution a heat-uncoagulable substance which gave a positive biuret reaction. Interest in the subject was stimulated by the investigation...

Some time ago a brief report (1) was made on the use of the Pulfrich photometer for the determination of sulfhydryl and disulfide compounds by a modified Folin (2) method. Since then the method has been extensively used in this laboratory (3-9). Folin’s method is based upon the observation that cystine plus sulfite gives a blue color with phospho-18-tungstic acid; whereas cystine alone develops...

The studies to be reported were undertaken with the idea of throwing more light on the proteins of the gastric juice. It has been found that they can be precipitated by tungstic acid at pH 3.5 and that, although heating coagulated a protein, there remained in solution a heat-uncoagulable substance which gave a positive biuret reaction. Interest in the subject was stimulated by the investigation...

The studies to be reported were undertaken with the idea of throwing more light on the proteins of the gastric juice. It has been found that they can be precipitated by tungstic acid at pH 3.5 and that, although heating coagulated a protein, there remained in solution a heat-uncoagulable substance which gave a positive biuret reaction. Interest in the subject was stimulated by the investigation...

Some time ago a brief report (1) was made on the use of the Pulfrich photometer for the determination of sulfhydryl and disulfide compounds by a modified Folin (2) method. Since then the method has been extensively used in this laboratory (3-9). Folin’s method is based upon the observation that cystine plus sulfite gives a blue color with phospho-18-tungstic acid; whereas cystine alone develops...

This study is focused on the composition and the evolution of tungstate ions solutions as a function of pH and increasing concentrations. The Raman analysis showed that, during the titration of the tungstate solutions, WO4(2-), HWO4- ions and probably W2O7(2-) , HW2O7(2-) and H2W2O7 solvated species could exist in aqueous solutions. For diluted solutions, additions of a strong acid does not cau...