Apparent Molecular Weight of Insulin in Dilute Acid Solution

Nature ◽  
1963 ◽  
Vol 197 (4872) ◽  
pp. 1104-1105 ◽  
Author(s):  
P. D. JEFFREY ◽  
J. H. COATES
Keyword(s):  
Molecular Weight ◽  
Acid Solution ◽  
Apparent Molecular Weight ◽  
Dilute Acid ◽  
Dilute Acid Solution

Semiautomated Method for the Analysis of Formulations of Chlorpheniramine Maleate and Brompheniramine Maleate

1979 ◽  
Vol 62 (3) ◽  
pp. 552-555
Author(s):  
Don C Cox ◽  
Ross D Kirchhoefer
Keyword(s):  
Acid Solution ◽  
Active Ingredient ◽  
Dilute Acid ◽  
Chlorpheniramine Maleate ◽  
Precision Data ◽  
Dilute Acid Solution ◽  
Aqueous Layer ◽  
Brompheniramine Maleate ◽  
Semiautomated Method

Abstract The determination of chlorpheniramine maleate and brompheniramine maleate in tablets, capsules, injections, and elixirs has been automated. The active ingredient is dissolved in dilute HCl. The dilute acid solution is sampled, made basic with dilute NaOH, and extracted with isooctane. The isooctane phase is resampled and the drug is re-extracted into dilute HCl. The absorbance of the acidic aqueous layer is monitored at 265 nm. The method is an automated version of the general USP XIX assay for salts of organic nitrogenous bases. The results from the semiautomated procedure agree well with the USP XIX and NF XIV official methods. Recoveries were 100% from an authentic tablet material. The system is linear from 0 to 300% of declared potency. The procedure is free from common excipient and dye interferences. Precision data are included for both the automated and official methods.

Hydrolysis equilibrium of dinitrogen trioxide in dilute acid solution

1981 ◽  
Vol 20 (2) ◽  
pp. 445-450 ◽  
Author(s):  
G. Y. Markovits ◽  
S. E. Schwartz ◽  
L. Newman
Keyword(s):  
Acid Solution ◽  
Dilute Acid ◽  
Dilute Acid Solution

Spectrophotometric Determination of Heroin Hydrochloride, Methapyrilene Hydrochloride, and Quinine Hydrochloride

1963 ◽  
Vol 46 (4) ◽  
pp. 637-641
Author(s):  
John D Endriz
Keyword(s):  
Acid Solution ◽  
Simultaneous Determination ◽  
Spectrophotometric Method ◽  
Extraction Methods ◽  
Maximum Absorption ◽  
Dilute Acid ◽  
Dilute Acid Solution ◽  
Quinine Hydrochloride ◽  
The Common

Abstract A rapid, accurate spectrophotometric method has been developed for the simultaneous determination of heroin, methapyrilene, and quinine in the presence of diluents commonly found in illicit narcotic samples. The absorbance curves for heroin, methapyrilene, and quinine show that at the points of maximum absorption of methapyrilene at 313 mμ and quinine at 348 mμ, methapyrilene and quinine do not seriously interfere with the maximum absorption of heroin at 280 mμ. Also, methapyrilene in dilute acid solution absorbs only slightly at the quinine maximum of 348 mμ. The common diluents such as lactose, mannitol, and starch usually found in illicit heroin mixtures do not interfere. The procedure described is sufficiently accurate for forensic purposes and has the advantage of speed over the extraction methods.

Inner glucosides of the anomeric 2-O-(2-hydroxyethyl)-D-glucoses

1969 ◽  
Vol 47 (9) ◽  
pp. 1592-1595 ◽  
Author(s):  
E. J. Roberts ◽  
S. P. Rowland
Keyword(s):  
Liquid Chromatography ◽  
Acid Solution ◽  
Gas Liquid Chromatography ◽  
Dilute Acid ◽  
Dilute Acid Solution

It has been found that 2-O-(2-hydroxyethyl)-D-glucopyranose is partially converted to 1,2-O-ethylene-α-D-glucofuranose, 1,2-O-ethylene-α-D-glucopyranose, and 1,2-O-ethylene-β-D-glucopyranose when heated in dilute acid solution. The ratio of the furanose derivative to the pyranose derivatives is dependent upon the concentration of the acid (3, 5). The three inner glucosides of 2-O-(2-hydroxyethyl)-D-glucose have been characterized by gas-liquid chromatography. The interrelationship of 2-O-(2-hydroxyethyl)-D-glucose and its inner glucosides is also reported.

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