scholarly journals Microcolorimetric Determination of Organic Sulfur by the Tin(II)-Strong Phosphoric Acid Reduction Method

1957 ◽  
Vol 30 (5) ◽  
pp. 482-486 ◽  
Author(s):  
Toshiyasu Kiba ◽  
Ikuko Akaza ◽  
née Kishi ◽  
Sachiko Taki
Keyword(s):  
Phosphoric Acid ◽  
Reduction Method ◽  
Organic Sulfur ◽  
Acid Reduction

Simplified Automated Method for Determination of Urinary or Serum Uric Acid, Based on Reduction of Ferric-Phenanthroline Complex

1975 ◽  
Vol 21 (1) ◽  
pp. 125-129 ◽  
Author(s):  
John W Nelson ◽  
K K Batra
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Reduction Method ◽  
Phosphotungstic Acid ◽  
Colorimetric Method ◽  
Automated Method ◽  
Phenanthroline Complex ◽  
Acidic Conditions ◽  
Acid Reduction

Abstract We describe an automated colorimetric method for determination of uric acid in serum or urine by use of an AutoAnalyzer II or SMA 12/60 (Technicon Corp.). The method depends on reduction of a ferric-phenanthroline complex by uric acid under acidic conditions to a ferrous-phenanthroline complex, which absorbs at 505 nm. Advantages of this method over other methods now in use are that color and concentration are linearly related (to 20 mg/100 ml); aqueous reagents are easily prepared, stable, and inexpensive; and interference from ascorbic acid has been eliminated by use of an alkaline copper-containing diluent. The analysis is also free of interference from glucose, creatinine, glutathione, salicylates and hemoglobin. Correlation with results of the Technicon phosphotungstic acid reduction method is excellent (r = .996). Correlation with results of an automated uricase method is satisfactory (r = .979). Recovery of uric acid was 101% over a wide concentration range.

Microcoulometric determination of total inorganic sulphur in water by a hydroiodic acid reduction method

1977 ◽  
Vol 92 (2) ◽  
pp. 267-275 ◽  
Author(s):  
M.C. van Grondelle ◽  
F. van de Craats ◽  
J.D. van der Laarse
Keyword(s):  
Reduction Method ◽  
Hydroiodic Acid ◽  
Inorganic Sulphur ◽  
Acid Reduction

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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