scholarly journals ON THE COLORIMETRIC DETERMINATION OF SMALL QUANTITIES OF PHOSPHORIC ACID AND OF SILICA.

1903 ◽  
Vol 25 (2) ◽  
pp. 169-184 ◽  
Author(s):  
F. P. Veitch
Keyword(s):  
Phosphoric Acid ◽  
Colorimetric Determination

The Colorimetric Determination of Phosphoric Acid in Hydrochloric Acid and Citric Acid Extracts of Soils

1930 ◽  
Vol 20 (4) ◽  
pp. 532-540 ◽  
Author(s):  
R. G. Warren ◽  
A. J. Pugh
Keyword(s):  
Citric Acid ◽  
Phosphoric Acid ◽  
Gravimetric Method ◽  
Potassium Ferrocyanide ◽  
Clay Soils ◽  
Acid Extraction ◽  
Colorimetric Determination ◽  
Colour Development ◽  
Good Agreement

1. The colorimetric determination of phosphoric acid in hydrochloric and citric acid extracts of soils by a method involving the evaporation of the extract, ignition and acid extraction of the residuewith either the Denigès and Fiske-Subbarow methods of colour development was satisfactory only with light soils. Clay soils gave low results owing to the presence of larger amounts of iron.2. A method is given in which the organic matter and iron are removed by treatment with sodium permanganate and potassium ferrocyanide. The results are in good agreement with the gravimetric method.

Colorimetric determination of phosphoric acid leakage for phosphoric acid-doped polybenzimidazole membrane fuel cell applications

2015 ◽  
Vol 299 ◽  
pp. 480-484 ◽  
Author(s):  
Yeon Hun Jeong ◽  
Ju Hae Jung ◽  
Euiji Choi ◽  
Seungyoon Han ◽  
Alina Irene Begley ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Phosphoric Acid ◽  
Colorimetric Determination

THE COLORIMETRIC DETERMINATION OF SOME SYNTHETIC OESTROGENS

1949 ◽  
Vol 27b (7) ◽  
pp. 646-652 ◽  
Author(s):  
R. A. Dunford
Keyword(s):  
Phosphoric Acid ◽  
Pharmaceutical Products ◽  
Ethylene Dichloride ◽  
Colorimetric Determination ◽  
Antimony Pentachloride ◽  
Photoelectric Colorimeter ◽  
Acid Reagent ◽  
Color Reactions ◽  
Phenol Reagent

The synthetic oestrogens, stilboestrol, hexoestrol, and dienoestrol give color reactions with nitric and nitrous acids, bromine, and certain phenol reagents, some of which can be adapted to their colorimetric determination. The use of Folin and Ciocalteu's phenol reagent is described for determination of the hormones in pharmaceutical products, using a Lumetron photoelectric colorimeter. The interference of other oestrogens and of phenolic preservatives and bactericides is considered and reference is made to a means of identifying the hormones by color reactions with antimony pentachloride in ethylene dichloride, and with an acetic – phosphoric acid reagent.

A Method for the Colorimetric Determination of β-Glucuronidase in Urine, Serum, Tissue; Assay of Enzymatic Activity in Health and Disease

1959 ◽  
Vol 36 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Julius A. Goldbarg ◽  
Esteban P. Pineda ◽  
Benjamin M. Banks ◽  
Alexander M. Rutenburg
Keyword(s):  
Enzymatic Activity ◽  
Colorimetric Determination ◽  
Health And Disease ◽  
Urine Serum

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

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