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.

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.

A New Approach to the Raney Catalyst Powder Method for Total Nitrogen in Fertilizers

1969 ◽  
Vol 52 (1) ◽  
pp. 23-30 ◽  
Author(s):  
J A Brabson ◽  
T C Woodis
Keyword(s):  
Sulfuric Acid ◽  
Refractory Compound ◽  
Potassium Sulfate ◽  
Dilute Solution ◽  
Commercial Alloy ◽  
New Approach ◽  
Powder Method ◽  
Catalyst Powder ◽  
Time Required

Abstract Further study of the Raney catalyst powder method for the determination of nitrogen in fertilizers established conditions in which the commercial alloy containing 50% Ni and 50% Al was a more efficient reductant for nitrates than an experimental alloy that contained 10% Co. Errors in measurement were decreased, accuracy was increased, and time was saved by adding all the sulfuric acid and part of the potassium sulfate as a single dilute solution and heating the mixture immediately to promote the reduction. Changes in the amounts of reagents, including use of the contents of a Kcl-Pak without the polyethylene envelope, resulted in smoother and more effective Kjeldahl digestions. The method is “rugged” and is equally applicable to the refractory compound nicotinic acid, mixtures of nitrates and organic materials, and the simplest inorganic fertilizers. The time required for an analysis can be further shortened by using “Autopettes” for dispensing the standard acid and a “Titralyzer” for back titrations.

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.

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

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.

Photometry of Inulin and Polyfructosan by Use of a Cysteine/ Tryptophan Reaction

1977 ◽  
Vol 23 (4) ◽  
pp. 639-645 ◽  
Author(s):  
William H Waugh
Keyword(s):  
Sulfuric Acid ◽  
Coefficient Of Variation ◽  
Biological Fluids ◽  
Cysteine Hydrochloride ◽  
Colorimetric Methods

Abstract Described are a macromethod for measuring 2 to 30 pg of polyfructoside in sample volumes of 0.5 ml and a mi¬cromethod for measuring 40 to 400 ng in 10-RI samples. The absorptivity of the cysteine/tryptophan color product is 2.5- to 10-fold those found with use of five other colorimetric methods for inulin. The method is highly specific for alkali-stable polyfructoside. Color, measured at 515 nm, was maximal on development at 56 °C for 25 min in dilute (57-58% by vol) sulfuric acid, after the addition of the combined cysteine hydrochloride/tryptophan reagent. Analytical recoveries of inulin and polyfructosan from plasma and urine were complete. With initial alkaline heating, the endogenous blank inulinoid values averaged 0.6 ± 0.47 (SD) mg/liter for plasma and 0.05 ± 0.024 mg/min for urine. The coefficient of variation of the macromethod was <3%; that for the micromethod ranged from 1.3 to 6.3%. The micromethod appears adaptable to the determination of nanogram quantities of polyfruc¬toside in nanoliter volumes of biological fluids.

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.

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