New Colorimetric Method for the Determination of Phosphate. II

An improved method for the colorimetric determination of phosphate.

ALL the known colorimetric methods for the determination of phosphate are liable to errors arising from (a) slight changes in acidity and concentration of reagents, and (b) the presence of interfering substances (e.g. fluorides, nitrites etc.). The following method is almost entirely independent of these disturbing factors, and possesses the added advantage of being more sensitive than those pr...

New Enzymatic Colorimetric Method for the Quantitative Determination of Phenylalanine in Dry-Blood Spots

Phenylketonuria (PKU) is an autosomal recessive disorder, which is characterized by severe mental retardation, microcephaly and seizures. The symptoms of this disease can be prevented if detected soon after birth. Therefore, blood Phenylalanine (Phe) measurement is essential for the early diagnosis, treatment and dietary monitoring of PKU patients. The goal of this research was to introduce a r...

A new simple semimicro method for colorimetric determination of urea.

New colorimetric method for quantitative determination of protein in urine.

Total urinary protein is rapidly precipitated at room temperature by tannic acid. The tannic acid/protein precipitate, dissolved in aqueous triethanolamine/ferric chloride solution, gives a purple-violet color of high absorptivity. Absorbance at 510 nm is linearly related to concentration from 0.05 to 1.50 A for a protein content of 0.05 to 1.50 g/liter, and less than 5 mg/liter can be detected...

Some Applications of the Colorimetric Phosphate Method

Two years ago, a modification (1) of the Bell-Doisy phosphate method was published and at that time technique ‘was given for its application to inorganic phosphorus in blood and urine. Since then its use has been extended to a variety of analytical procedures, some of which are given below. In principle the method consists of the formation of phosphomolybdic acid and its subsequent reduction by...