scholarly journals Application of Ninhydrin-Sulfuric Acid Reagent to the Determination of Micro Amounts of 3-Dimethylamino-1, 1-di(2-thienyl)but-1-ene (Ohton)

1967 ◽  
Vol 15 (5) ◽  
pp. 701-703 ◽  
Author(s):  
Mikiko Kataoka ◽  
Takeshi Miyata ◽  
Keiko Yogi ◽  
Yoshitoshi Kase
Keyword(s):  
Sulfuric Acid ◽  
Acid Reagent

Test for the Determination of Starch in Meat Food Products (Applicable for Estimation of Cereal in Sausages)

1966 ◽  
Vol 49 (2) ◽  
pp. 307-309
Author(s):  
W Glover ◽  
H Kirschenbaum ◽  
A Caldwell
Keyword(s):  
Sulfuric Acid ◽  
Perchloric Acid ◽  
Food Products ◽  
Acid Reagent ◽  
Good For

Abstract A method has been developed for determining starch in meat food products in which simple sugars are extracted from meat food products with hot 80% ethanol while starch remains. The starch residue is solublized with dilute perchloric acid, readily forms a colored derivative when heated with anthrone-sulfuric acid reagent, and is measured at 630 mμ. It was not necessary to prepare a standard dextrose curve daily. The anthrone-sulfuric acid reagent is good for 3–4 days if kept near 0.0°C.

scholarly journals A Validated Quantitative Thin-Layer Chromatographic Method for Estimation of Diosgenin in Various Plant Samples, Extract, and Market Formulation

2007 ◽  
Vol 90 (2) ◽  
pp. 358-363 ◽  
Author(s):  
Priti D Trivedi ◽  
Kilambi Pundarikakshudu ◽  
Shivprakash Rathnam ◽  
Karishma S Shah
Keyword(s):  
Sulfuric Acid ◽  
Thin Layer ◽  
Chromatographic Method ◽  
Detection Sensitivity ◽  
Fenugreek Seed ◽  
Plant Samples ◽  
Relative Standard ◽  
Leaf Powder ◽  
Acid Reagent

Abstract A sensitive and reproducible thin-layer chromatographic method has been developed for quantitation of diosgenin, a spiroketal sapogenin. The spots were visualized by spraying with modified anisaldehyde-sulfuric acid reagent. The concentration of anisaldehyde was reduced to 0.1% instead of 1%, and the concentration of sulfuric acid was kept at a minimum of 2%. This successfully reduced charring and background interference. The method was validated according to International Conference on Harmonization guidelines. The method was used for determination of diosgenin from dried samples of fenugreek seeds, leaves, stem, seed extracts, and a polyherbal antidiabetic formulation containing fenugreek powder as one of the ingredients. Increased detection sensitivity was observed with linearity from 98 to 588 ng/spot and a correlation coefficient (r2) of 0.988. The relative standard deviation value for linearity of the method was found to be 0.18%. The method was successfully applied to various plant samples of fenugreek (Methi) with a recovery of 98.11 ± 1.4%. Dried plant samples and a market formulation were analyzed and found to contain diosgenin in the range of 0.5290.658% (w/w) in fenugreek seed powders, 0.087% (w/w) in fenugreek leaf powder, 0.015 and 1.27% (w/w) in fenugreek stem powder and extract, respectively, and 0.586% (w/w) in a formulation containing fenugreek seed powder. No matrix interference was observed.

Toxicologic Studies on Hydrocarbons. VI. A Colorimetric Method for the Determination of Kerosine in Blood

1960 ◽  
Vol 6 (4) ◽  
pp. 327-331 ◽  
Author(s):  
Horace W Gerarde ◽  
Paul Skiba
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Quantitative Determination ◽  
Calibration Curve ◽  
Colorimetric Method ◽  
Acid Reagent

Abstract A photoelectric colorimetric method is described for the quantitative determination of kerosine in blood. The procedure involves hemolysis of 5 ml. of the sample followed by extraction of the kerosine with carbon tetrachloride. The extract is reacted with a formaldehyde- sulfuric acid reagent to produce a characteristic color. The intensity of this color is measured photometrically, and the concentration of kerosine is determined by reference to a previously prepared calibration curve. Concentrations as low as 10 ppm can be conveniently determined.

Study of sugars with cysteine – sulfuric acid reagents

1969 ◽  
Vol 47 (2) ◽  
pp. 203-206 ◽  
Author(s):  
R. J. Thibert ◽  
A. Mazzuchin
Keyword(s):  
Sulfuric Acid ◽  
Optimum Concentration ◽  
Complete Analysis ◽  
Cysteine Hydrochloride ◽  
Acid Reagent ◽  
Time Required ◽  
Optimum Concentration Range

A modified procedure for the use of the cysteine – sulfuric acid reagent for the determination of monosaccharide has been devised. The procedure utilizes a 9-ml volume of H2O:H2SO4 at a ratio of 1:7 which results in a rapid nonspecific method for the determination of pentoses, hexoses, and hexuronic acids in simple solutions. α-Substituted cysteines are compared to cysteine hydrochloride as color reagents. The accuracy of the modified procedure is about ± 2% in the optimum concentration range. The time required for a complete analysis is about 1 h for pentoses and hexuronic acids and 30 min for hexoses.

Colorimetric Determination of Ethinyl Estradiol in Oral Contraceptive Formulations

1974 ◽  
Vol 57 (3) ◽  
pp. 747-751
Author(s):  
John Y P Wu
Keyword(s):  
Sulfuric Acid ◽  
Oral Contraceptive ◽  
Ethinyl Estradiol ◽  
Chromatographic Column ◽  
Colorimetric Determination ◽  
Color Formation ◽  
Coefficients Of Variation ◽  
Label Claim ◽  
Acid Reagent

Abstract Ethinyl estradiol in oral contraceptive formulations is separated from the sample on a chromatographic column prior to color formation with methanol-sulfuric acid reagent directly in the chloroform-isooctane eluate. Collaborative results on 3 commercial tablet samples averaged 93.93, 98.69, and 98.50% of label claim. The standard deviations and coefficients of variation were 2.61, 2.39, and 2.82, and 2.77, 2.43, and 2.86%, respectively. The method has been adopted as official first action.

A Modified Procedure for the Estimation of Total 17-Hydroxycorticosteroids (Porter-Silber Chromogens) in Urine

1964 ◽  
Vol 10 (2) ◽  
pp. 103-115 ◽  
Author(s):  
John HC Liu
Keyword(s):  
Sulfuric Acid ◽  
Sodium Chloride ◽  
Ethyl Ether ◽  
Salt Effect ◽  
Ph Effect ◽  
Single Extraction ◽  
Extraction Step ◽  
Acid Reagent ◽  
The Stability

Abstract A modified procedure for the determination of urinary 17-hydroxycorticosteroids (di-hydroxy-acetonyl-corticoids) is described. The use of ethyl ether in a single extraction step and the stabilization of the phenylhydrazine-sulfuric acid reagent with sodium chloride are the unique features of the method. Studies of chromogenicities of steroids, recovery, pH effect on extraction, and salt effect on the stability of Porter-Silber reagent in the presence and absence of light during storage are reported; chemical aspects of chromogenic development of various steroids are discussed, clinical ranges compared, and interpretations evaluated.

Colorimetric Determination of Ethinyl Estradiol in Oral Contraceptive Formulations

1974 ◽  
Vol 57 (3) ◽  
pp. 756-760
Author(s):  
John Y P Wu
Keyword(s):  
Sulfuric Acid ◽  
Oral Contraceptive ◽  
Ethinyl Estradiol ◽  
Chromatographic Column ◽  
Colorimetric Determination ◽  
Color Formation ◽  
Coefficients Of Variation ◽  
Label Claim ◽  
Acid Reagent

Abstract Ethinyl estradiol in oral contraceptive formulations is separated from the sample on a chromatographic column prior to color formation with methanol-sulfuric acid reagent directly in the chloroform-isooctane eluate. Collaborative results on 3 commercial tablet samples averaged 93.93, 98.69, and 98.50% of label claim. The standard deviations and coefficients of variation were 2.61, 2.39, and 2.82, and 2.77, 2.43, and 2.86%, respectively. The method has been adopted as official first action.

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

Improved Method for the Determination of Ethylenebisdithiocarbamate Residues in Plants, Fruits, and Vegetables

1967 ◽  
Vol 50 (5) ◽  
pp. 1102-1108
Author(s):  
Charles F Gordon ◽  
Richard J Schuckert ◽  
William E Bornak
Keyword(s):  
Sulfuric Acid ◽  
Fruits And Vegetables ◽  
Analytical Procedure ◽  
Improved Method ◽  
Modified Method ◽  
Fungicide Residues ◽  
Crop Types ◽  
Large Representative

Abstract A modified method for the determination of dithiocarbamate fungicide residues on crops is presented. A large representative subsample of the frozen crop is blended in ice-cold deaerated water and an aliquot of the homogenate is added to the analytical apparatus containing hot 5 0% sulfuric acid. Dithiocarbamates are decomposed to evolve CS2 which is removed by a continuous gentle air-sweep from the digestion flask. Variations in technique allow the analysis of dithiocarbamate fungicide residues in several ranges, 1-10, 10-200, and 200-1000 /ig maneb. Recoveries from a wide variety of crops averaged 70 to 103%. Certain crop types present low recoveries and/or high apparent control values, but modifications in the analytical procedure are successful in solving these problems.

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