THE DETERMINATION OF TRYPTOPHANE BY A MODIFIED GLYOXYLIC ACID METHOD EMPLOYING PHOTOELECTRIC COLORIMETRY

1938 ◽  
Vol 16b (10) ◽  
pp. 361-368 ◽  
Author(s):  
J. L. D. Shaw ◽  
W. D. McFarlane
Keyword(s):  
Formic Acid ◽  
Sodium Hydroxide ◽  
Reliable Method ◽  
Glyoxylic Acid ◽  
Acid Method ◽  
Photoelectric Colorimeter ◽  
Acid Reaction ◽  
Alkali Hydrolysis ◽  
Hydrolysis Of

An accurate and reliable method for the estimation of tryptophane is described. It is based on the glyoxylic acid reaction, and involves the use of the Evelyn photoelectric colorimeter. The technique makes it possible to ascertain readily whether the color being measured is due only to tryptophane.The method has been applied to casein, of which, if necessary, only 25 mg. is required. The tryptophane determination is readily accomplished on a solution obtained by dissolving the casein in 10 or 20% sodium hydroxide or 5% formic acid by heating for a few minutes. With respect to alkali hydrolysis of casein under pressure, tryptophane is unstable in the sodium hydroxide hydrolysis, but is very stable in the baryta hydrolysis. The age and source of the casein are shown to be factors causing variations in the tryptophane content of different samples of casein, a variability which has been observed by a few previous workers.

Structure Determination of Formic Acid Reaction Products on TiO2(110)†

2004 ◽  
Vol 108 (38) ◽  
pp. 14316-14323 ◽  
Author(s):  
D. I. Sayago ◽  
M. Polcik ◽  
R. Lindsay ◽  
R. L. Toomes ◽  
J. T. Hoeft ◽  
...  
Keyword(s):  
Formic Acid ◽  
Structure Determination ◽  
Reaction Products ◽  
Acid Reaction

scholarly journals Highly Sensetive Reaction for the Estimation of Carbaryl Using 4-4ˊ- Diaminodiphenyl Sulfone in Environmental Samples

2006 ◽  
Vol 3 (4) ◽  
pp. 250-256
Author(s):  
Besagarahally L. Bhaskara ◽  
Padmarajaiah Nagaraja
Keyword(s):  
Environmental Samples ◽  
Absorption Maximum ◽  
Environmental Water ◽  
Good Alternative ◽  
Water Soluble ◽  
Diaminodiphenyl Sulfone ◽  
Ultra Trace ◽  
Alkali Hydrolysis ◽  
Hydrolysis Of

A rapid, sensitive Spectrophotometric method for the determination of ultra trace amount of carbaryl (1- Napthyl-N- Methyl Carbamate) is proposed. The method is based on an alkali hydrolysis of carbaryl in the presence of methanolic KOH, followed by coupling with diazotized 4-41- diaminodiphenyl sulfone in an alkaline medium. The water soluble pink dye obtained shows an absorption maximum at 540 nm. The system obeys Beer’s law over the range of 0.06-2.0μg mL-1. The absorptivity of the coloured product is 7.014 × 104l mol-1cm-1and the developed colour is stable for 48h. The detection limit of Carbaryl is 0.0102 μg mL-1. This method is a very good alternative tool and it can be used successfully for the determination of carbaryl residue in environmental water and grain samples.

scholarly journals A simple method for the spectrophotometric determination of cephalosporins in pharmaceuticals using variamine blue

2018 ◽  
Vol 33 (2) ◽  
pp. 41
Author(s):  
Chand Pasha ◽  
Badiadka Narayana
Keyword(s):  
Sodium Hydroxide ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Acidic Medium ◽  
Simple Method ◽  
Lactam Ring ◽  
Ph Range ◽  
Variamine Blue ◽  
Hydrolysis Of

A simple spectrophotometric method for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin with variamine blue is presented. The determination is based on the hydrolysis of β-lactam ring of cephalosporins with sodium hydroxide which subsequently reacts with iodate to liberate iodine in acidic medium. The liberated iodine oxidizes variamine blue to violet colored species of maximum absorption at 556 nm. The absorbance is measured within the pH range of 4.0-4.2. Beer’s law is obeyed in the range of 0.5-5.8 μg mL–1, 0.2-7.0 μg mL–1, 0.2-5.0 μg mL–1 and 0.5-8.5 μg mL–1 for cefotaxime, ceftriaxone, cefadroxil and cephalexin respectively. The analytical parameters were optimized and the method is successfully applied for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin in pharmaceuticals.

A CHEMICAL PROCEDURE FOR DETERMINATION OF THE C14-DISTRIBUTION IN LABELLED XYLOSE

1955 ◽  
Vol 33 (1) ◽  
pp. 368-373 ◽  
Author(s):  
Stewart A. Brown
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Glycolic Acid ◽  
Periodic Acid ◽  
Glyoxylic Acid ◽  
Lead Tetraacetate ◽  
Carbon 14 ◽  
Chemical Procedure ◽  
Purified Salt

A series of reactions reported previously for the degradation of glucose has been modified and extended to permit the determination of carbon-14 in each of the five carbons of a single 2 mM. xylose sample. Methyl xylopyranoside was oxidized with periodic acid giving C-3 as formic acid, and a dialdehyde which was converted to strontium methoxy-diglycolate. The purified salt was hydrolyzed to glyoxylic and glycolic acids. The glyoxylic acid was isolated as the 2, 4-dinitrophenylhydrazone (C-1 + C-2) which was decarboxylated to give carbon dioxide from C-2. The glycolic acid was oxidized by lead tetraacetate to give C-4 as carbon dioxide and C-5 as formaldehyde. The activity in C-1 was determined by difference. The method was applied to xylose-1-C14, xylose-5-C14, and a biologically synthesized xylose sample with satisfactory results. This degradation procedure is theoretically applicable to other aldopentoses and aldotetroses.

A CHEMICAL PROCEDURE FOR DETERMINATION OF THE C14-DISTRIBUTION IN LABELLED XYLOSE

1955 ◽  
Vol 33 (3) ◽  
pp. 368-373 ◽  
Author(s):  
Stewart A. Brown
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Glycolic Acid ◽  
Periodic Acid ◽  
Glyoxylic Acid ◽  
Lead Tetraacetate ◽  
Carbon 14 ◽  
Chemical Procedure ◽  
Purified Salt

A series of reactions reported previously for the degradation of glucose has been modified and extended to permit the determination of carbon-14 in each of the five carbons of a single 2 mM. xylose sample. Methyl xylopyranoside was oxidized with periodic acid giving C-3 as formic acid, and a dialdehyde which was converted to strontium methoxy-diglycolate. The purified salt was hydrolyzed to glyoxylic and glycolic acids. The glyoxylic acid was isolated as the 2, 4-dinitrophenylhydrazone (C-1 + C-2) which was decarboxylated to give carbon dioxide from C-2. The glycolic acid was oxidized by lead tetraacetate to give C-4 as carbon dioxide and C-5 as formaldehyde. The activity in C-1 was determined by difference. The method was applied to xylose-1-C14, xylose-5-C14, and a biologically synthesized xylose sample with satisfactory results. This degradation procedure is theoretically applicable to other aldopentoses and aldotetroses.

A CHEMICAL PROCEDURE FOR DETERMINATION OF THE C14-DISTRIBUTION IN LABELED GLUCOSE

1955 ◽  
Vol 33 (1) ◽  
pp. 62-68 ◽  
Author(s):  
B. Boothroyd ◽  
Stewart A. Brown ◽  
J. A. Thorn ◽  
A. C. Neish
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Periodic Acid ◽  
Glyoxylic Acid ◽  
Glyceric Acid ◽  
Diglycolic Acid ◽  
Glucose Molecule ◽  
Strontium Salt ◽  
Chemical Procedure

A procedure based on the work of Jackson and Hudson was developed for the degradation of methyl-α-D-glucopyranoside formed from 2 millimoles of glucose. Oxidation of the glucoside with periodic acid gave C-3 as formic acid and a dialdehyde which was converted to the strontium salt of D′-methoxy-D-hydroxymethyl diglycolic acid. The purified salt was hydrolyzed to glyoxylic and glyceric acids. The glyoxylic acid was isolated as the 2,4-dinitrophenylhydrazone (C-1 + C-2); this was decarboxylated by heat to give carbon dioxide from C-2. The glyceric acid was oxidized by periodate to give C-4 as carbon dioxide, C-5 as formic acid, and C-6 as formaldehyde. This degradation permitted the determination of C14 in each position of the glucose molecule, the activity in C-1 being determined by difference. The method was applied to glucose-1-C14 and a sample of glucose labeled in all positions with satisfactory results.

THE DETERMINATION OF NITRATES IN COLORED SOIL EXTRACTS

1949 ◽  
Vol 27b (2) ◽  
pp. 76-80 ◽  
Author(s):  
F. J. Sowden ◽  
H. J. Atkinson
Keyword(s):  
Hydrochloric Acid ◽  
Acid Solution ◽  
Sodium Hydroxide ◽  
Steam Distillation ◽  
Sodium Hydroxide Solution ◽  
Soil Extracts ◽  
Satisfactory Method ◽  
Photoelectric Colorimeter ◽  
Coloring Matter

In highly colored soil extracts, it was found impossible to determine nitrates directly by the phenoldisulphonic acid color reaction. Attempts to remove the coloring matter by oxidation or absorption were not successful. The most satisfactory method was found to be reduction of the nitrate to ammonia with Devarda's alloy in 0.1 N sodium hydroxide solution in the cold after the removal by steam distillation, of any ammonia that might be present in the extract. The ammonia formed from the nitrate was steam distilled into 0.01 N hydrochloric acid solution and determined colorimetrically by Nessler's reagent using a Klett–Summerson photoelectric colorimeter. The recovery of nitrates from the colored solutions and from standards was satisfactory. The aliquot taken for the determination should contain not more than 0.125 mgm. nitrogen as nitrate.

A CHEMICAL PROCEDURE FOR DETERMINATION OF THE C14-DISTRIBUTION IN LABELED GLUCOSE

1955 ◽  
Vol 33 (1) ◽  
pp. 62-68 ◽  
Author(s):  
B. Boothroyd ◽  
Stewart A. Brown ◽  
J. A. Thorn ◽  
A. C. Neish
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Periodic Acid ◽  
Glyoxylic Acid ◽  
Glyceric Acid ◽  
Diglycolic Acid ◽  
Glucose Molecule ◽  
Strontium Salt ◽  
Chemical Procedure

A procedure based on the work of Jackson and Hudson was developed for the degradation of methyl-α-D-glucopyranoside formed from 2 millimoles of glucose. Oxidation of the glucoside with periodic acid gave C-3 as formic acid and a dialdehyde which was converted to the strontium salt of D′-methoxy-D-hydroxymethyl diglycolic acid. The purified salt was hydrolyzed to glyoxylic and glyceric acids. The glyoxylic acid was isolated as the 2,4-dinitrophenylhydrazone (C-1 + C-2); this was decarboxylated by heat to give carbon dioxide from C-2. The glyceric acid was oxidized by periodate to give C-4 as carbon dioxide, C-5 as formic acid, and C-6 as formaldehyde. This degradation permitted the determination of C14 in each position of the glucose molecule, the activity in C-1 being determined by difference. The method was applied to glucose-1-C14 and a sample of glucose labeled in all positions with satisfactory results.

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