A simple method for the determination of 5-vinyloxazolidine-2-thione in rapeseed meal

1969 ◽  
Vol 47 (8) ◽  
pp. 817-818 ◽  
Author(s):  
A. Szewczuk ◽  
P. Mastalerz ◽  
W. Nadwyczawski
Keyword(s):  
Organic Solvents ◽  
Aqueous Phase ◽  
Rapeseed Meal ◽  
New Method ◽  
Simple Method ◽  
Titrimetric Method ◽  
Azide Ion ◽  
The Family ◽  
Titrimetric Determination

5-Vinyloxazolidine-2-thione (VOT), a goitrogenic substance occurring in plants of the family Cruciferae, was found to catalyze the reduction of iodine by azide ion, the consumption of iodine being proportional to the amount of VOT. Based on these observations, a sensitive, titrimetric method of VOT determination was developed. The new method obviates the necessity of VOT extraction from the aqueous phase with organic solvents. Sensitivity and accuracy of titrimetric determination of VOT are comparable with those of spectrophotometric procedures.

Determination of unconjugated 3-methoxy-4-hydroxyphenylglycol by liquid chromatography for monitoring inhibition of monoamine oxidase activity in plasma.

1987 ◽  
Vol 33 (11) ◽  
pp. 2078-2080 ◽  
Author(s):  
R N Gupta ◽  
M Steiner ◽  
M Lew
Keyword(s):  
Liquid Chromatography ◽  
Monoamine Oxidase ◽  
Ethyl Acetate ◽  
Aqueous Phase ◽  
Oxidase Activity ◽  
Back Extraction ◽  
Monoamine Oxidase Activity ◽  
Simple Method ◽  
Extraction Recovery

Abstract We describe a simple method for extracting 3-methoxy-4-hydroxyphenylglycol (MHPG) from plasma. The sample is applied to a 1-mL "Extrelut" column (EM Industries) and eluted 15 min later with ethyl acetate. After mixing the eluate with pentane and back-extraction into water, we inject 25 or 50 microL of the aqueous phase onto a Beckman 15 cm x 4.6 mm (i.d.) column packed with 5-micron ODS particles (Beckman). Peaks are detected with a coulometric detector. The resulting chromatogram is clean, with few extraneous peaks. The extraction recovery of MHPG is 55-60%, which allows for detection of as little as 0.2 microgram of the analyte per liter. The decrease in the concentration of MHPG in plasma of patients treated with phenelzine agrees with the decrease in monoamine oxidase activity in platelets of these patients.

A new method for the titrimetric determination of the ferricyanide ion

Talanta ◽  
1958 ◽  
Vol 1 (4) ◽  
pp. 305-309 ◽  
Author(s):  
F. Lucena-Conde ◽  
I.Sánchez Bellido
Keyword(s):  
New Method ◽  
Titrimetric Determination

A New Method for the Determination of Ascorbic Acid in Urine

1964 ◽  
Vol 10 (7) ◽  
pp. 575-580 ◽  
Author(s):  
Lee Kum-Tatt ◽  
P C Leong
Keyword(s):  
Ascorbic Acid ◽  
Potassium Iodide ◽  
Mercuric Chloride ◽  
New Method ◽  
Potassium Iodide Solution ◽  
Sodium Thiosulphate ◽  
Simple Method ◽  
Mercurous Chloride ◽  
Iodide Solution

Abstract A simple method for the determination of ascorbic acid in urine was developed. The method is based on the quantitative reduction of mercuric chloride to mercurous chloride at pH 3.5-5.0. The insoluble mercurous chloride was separated by centrifugation, dissolved in excess standard iodine-potassium iodide solution and back-titrated with standard sodium thiosulphate. The method has precision, and as little as 1.0 mg. of ascorbic acid per 100 ml. of urine can be determined with an accuracy of ± 3%. Common substances found in urine do not interfere.

Simple enzymatic determination of total cholesterol in gallstones.

1989 ◽  
Vol 35 (11) ◽  
pp. 2247-2249 ◽  
Author(s):  
J S Wei ◽  
H M Huang ◽  
W C Shyu ◽  
C S Wu
Keyword(s):  
Total Cholesterol ◽  
Dimethyl Sulfoxide ◽  
Organic Solvents ◽  
Cholesterol Oxidase ◽  
Enzymatic Activities ◽  
Simple Method ◽  
Spectroscopic Measurements ◽  
Assay Mixture ◽  
Enzymatic Determination

Abstract In this simple method for rapid enzymatic determination of total cholesterol in human gallstones, gallstone powder is dissolved in an 80/20 by vol mixture of N,N-dimethylformamide and dimethyl sulfoxide and reacted directly with the aqueous enzymatic reagent, without further treatment. The organic solvents do not interfere with enzymatic activities of cholesterol oxidase, esterase, and peroxidase in the assay mixture. The method is reproducible (CVs 3.7% to 6.6%), analytical recoveries ranged from 98.6% to 102%, and linearity is good. Furthermore, results correlated well with those obtained by infrared spectroscopic measurements.

scholarly journals A new method for the quantitative determination of monosaccharides, amino sugars and N-acetylneuraminic acid and of 6-deoxyhexose (fucose) in the presence of other sugars

1968 ◽  
Vol 110 (3) ◽  
pp. 413-417 ◽  
Author(s):  
Gwyneth M. Brearley ◽  
Jacqueline B. Weiss
Keyword(s):  
Quantitative Determination ◽  
Colorimetric Assay ◽  
Periodate Oxidation ◽  
New Method ◽  
Amino Sugars ◽  
Simple Method ◽  
Acetylneuraminic Acid ◽  
Assay Procedure ◽  
Optimum Ph

1. Monosaccharides, amino sugars and N-acetylneuraminic acid were determined by using an original colorimetric assay procedure, based on the detection of formaldehyde released after periodate oxidation. A range of these compounds was investigated by this method and they were all found to obey Beer's law within the concentration range 0–0·6μmole/ml. 2. A simple method for the determination of 6-deoxyhexose concentration in the presence of other monosaccharides is also described. 3. The optimum pH for the release of formaldehyde from sugars by periodate oxidation was 7·0–7·5. 4. The methods described have considerable advantages over existing assay systems and their particlar value in automatic colorimetry, where the use of concentrated acids is undesirable, is discussed.

A new method for the determination of the cytotoxicity of bile acids and aqueous phase of stool: the effect of calcium

1993 ◽  
Vol 23 (12) ◽  
pp. 773-777 ◽  
Author(s):  
I. P. VAN MUNSTER ◽  
A. TANGERMAN ◽  
A. F. J. DE HAAN ◽  
F. M. NAGENGAST
Keyword(s):  
Bile Acids ◽  
Aqueous Phase ◽  
New Method

Solubility Determination of Cholesterol Polymorphs in Organic Solvents

1966 ◽  
Vol 12 (4) ◽  
pp. 206-210 ◽  
Author(s):  
Royce D Stauffer ◽  
Fritz Bischoff
Keyword(s):  
Olive Oil ◽  
Organic Solvents ◽  
Aqueous Phase ◽  
Higher Alcohols ◽  
Solubility Determination ◽  
Crystalline Forms

Abstract In a study of the solubility of crystalline forms of cholesterol in various solvents, the solubilities (per cent by weight) of cholesterol needles and hydrated plates at 38° were, respectively, 4.0 and 3.2% in olive oil; 2.6 and 1.9% in tetradecane; 26.2 and 9% in toluene; and 21.0 and 7% in cyclohexane. When these solvents are in equilibrium with an aqueous phase, needles are converted to plates. Pseudomorph ( dehydrated) plates in olive oil have the solubility of needles. These differences may have significance in studies involving cholesterol pathogenesis. The modified Zak reaction with ethanol could not be used for the assay of cholesterol in olive oil since the reaction product was turbid. Higher alcohols were studied as a substitute for ethanol; 2-propanol was satisfactory.

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