Determination of organic pharmaceuticals with N-bromosuccinimide. Part III. Some pyrazolone derivatives by direct titration

The Analyst ◽  
1982 ◽  
Vol 107 (1278) ◽  
pp. 1054 ◽  
Author(s):  
B. A. El-Zeany ◽  
M. M. Amer ◽  
A. M. Taha ◽  
O. A. El-Sawy
Keyword(s):  
Direct Titration ◽  
Pyrazolone Derivatives

Adaptation of the AOAC Fluorine Method for Determining Fluoride in Fish Protein Concentrate

1970 ◽  
Vol 53 (1) ◽  
pp. 3-6
Author(s):  
R. Bruce Klemm ◽  
Mary E. Ambrose Klemm
Keyword(s):  
Steam Distillation ◽  
Silica Sand ◽  
Official Method ◽  
Protein Concentrate ◽  
Fish Protein ◽  
Direct Titration ◽  
Modified Method ◽  
Aoac Official ◽  
Aoac Official Method

Abstract The AOAC official method, 24.029–24.035, for the determination of fluorine in foods was modified slightly to o btain quantitative recoveries of fluorine from samples of fish protein concentrate (FPC). The most important alterations include the use of steam distillation, the addition of finely ground silica sand in the distillation, a decrease in the distillation temperature, and the utilization of direct titration. Recoveries of fluoride added to FPC before ashing, using this modified method, averaged 96.0 ± 3.0%. Our results are in agreement with those of several other analysts who used a variety of methods.

Quantitative determination of acidic groups in functionalized graphene by direct titration

2016 ◽  
Vol 103 ◽  
pp. 44-53 ◽  
Author(s):  
Jakub Ederer ◽  
Pavel Janoš ◽  
Petra Ecorchard ◽  
Václav Štengl ◽  
Zuzana Bělčická ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Functionalized Graphene ◽  
Direct Titration

Analysis of Sodium Diphenylhydantoin and Phenobarbital Combinations by Nonaqueous Titration

1968 ◽  
Vol 51 (5) ◽  
pp. 1013-1016
Author(s):  
Sura J P Agarwal ◽  
Martin I Blake
Keyword(s):  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Ammonium Hydroxide ◽  
Butyl Alcohol ◽  
Dosage Forms ◽  
Direct Titration ◽  
Titration Procedure ◽  
Tert Butyl Alcohol ◽  
Preliminary Separation

Abstract A simple, nonaqueous titration procedure is described for the determination of sodium diphenylhydantoin and phenobarbital combinations. Preliminary separation of the components is unnecessary. The phenobarbital content is determined by direct titration in tert.-butyl alcohol, using sodium methoxide or triethyl n-butyl ammonium hydroxide as the titrant. The total acidity is determined by titration of the sample after passage through a cation exchange resin (Amberlite IRC-50). The sodium diphenylhydantoin content is obtained by difference. Quantitative recoveries were obtained for synthetic mixtures and commercially available dosage forms

Potentiometric Determination of Chlorides in Wine, Distilled Spirits, and Wine Vinegar

1966 ◽  
Vol 49 (3) ◽  
pp. 498-501
Author(s):  
Clifford E Hubach
Keyword(s):  
Silver Nitrate ◽  
Collaborative Study ◽  
Potentiometric Determination ◽  
End Point ◽  
Direct Titration ◽  
Distilled Spirits ◽  
Wine Vinegar ◽  
High Degree

Abstract Collaborative study of the Pro method for determining chlorides in wines and distilled spirits by direct titration with silver nitrate followed by potentiometric reading of the end point gave accurate and reproducible results. The procedure is suitable for repetitious analyses in control laboratories, and it is also adaptable to determinations requiring a high degree of precision. Recoveries of chloride added to samples averaged 99.7%. The method is recommended for adoption as official, first action.

scholarly journals SIMULTANEOUS HYDROLYSES OF ESTERS AND PROTEINS AT SATURATION LEVELS

1958 ◽  
Vol 41 (3) ◽  
pp. 485-500 ◽  
Author(s):  
M. Castañeda-Agulló ◽  
Luz M. Del Castillo
Keyword(s):  
Enzyme System ◽  
Kinetic Studies ◽  
Direct Titration ◽  
Enzyme Substrate ◽  
Constant Ph ◽  
Potentiometric Measurement ◽  
The Individual ◽  
Hydrolysis Of ◽  
Protein Enzyme

A direct titration method for the determination of proteolytic activity is discussed. This involves the potentiometric measurement of the volume of 0.08 N NaOH required to maintain a constant pH (8.0) during the time of the hydrolysis. It is a sensitive method which presents several advantages; viz., it measures simultaneously protease and esterase activity, it follows the hydrolysis very closely and from the first stages; the titration is continuous and on the same sample. This method determines a constant fraction of the groups titratable by formol titration. The ratio formol: direct titration is represented by a factor "f" which is presumed to be distinct for each protein-enzyme system. Kinetic studies, using this method, revealed that the rates of hydrolysis of mixtures casein-gelatin on one hand, casein-BAEE or gelatin-BAEE on the other, are always larger than those of the corresponding isolated substrates. In many cases the resulting rates are equal or nearly equal to the sum of the individual rates, even though the mentioned rates have been determined within the saturation zones for every substrate. The former observations are inconsistent with the theory of the formation of an intermediary enzyme-substrate compound, unless it is assumed that the enzyme has a specific active group for each substrate.

scholarly journals STUDIES ON RDX AND RELATED COMPOUNDS: IX. DETERMINATION OF NITRIC ACID AND ACETIC ANHYDRIDE IN BACHMANN LIQUORS

1953 ◽  
Vol 31 (3) ◽  
pp. 201-203
Author(s):  
R. H. Betts ◽  
R. S. Stuart ◽  
C. A. Winkler
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Ammonium Nitrate ◽  
Routine Analysis ◽  
Calcium Hypochlorite ◽  
Electrometric Method ◽  
Direct Titration ◽  
Related Compounds ◽  
External Indicator

An electrometric method for determination of nitric acid in RDX(B) liquors has been developed. The method is not largely affected by ammonium nitrate and acetic anhydride. A precision of ± 0.5% may be readily obtained. Acetic anhydride in RDX(B) liquors may be determined by direct titration with standard aniline–toluene solution at 0 °C., using calcium hypochlorite as an external indicator. In routine analysis, a precision of ± 2% may be obtained.

ESTIMATION OF CARBOXYL, ALDEHYDE, AND KETONE GROUPS IN CHROMIUM TRIOXIDE OXYSTARCHES

1953 ◽  
Vol 31 (9) ◽  
pp. 801-813 ◽  
Author(s):  
A. C. Ellington ◽  
C. B. Purves
Keyword(s):  
Corn Starch ◽  
Chromium Trioxide ◽  
Hydroxylamine Hydrochloride ◽  
Hydriodic Acid ◽  
Carbonyl Groups ◽  
Sodium Bisulphite ◽  
Direct Titration ◽  
Hydrolysis Of ◽  
Bromide Solutions

Under identical conditions, corn starch amylose was more readily oxidized than the amylopectin by chromium trioxide dissolved in acetic acid – acetic anhydride, which was a nonswelling system. These differences in rate nearly vanished for samples dried through solvent exchange when the oxidant was dissolved in a swelling medium, 0.2 M aqueous sulphuric acid. The absolute rate of oxidation, however, was greatly reduced.Carboxyl groups in the oxystarches were satisfactorily estimated either by ion-exchange with calcium acetate or sodium bromide solutions, or by direct titration to about pH 8.5 with aqueous alkali. The samples retained chromium compounds which grossly interfered with the determination of total carbonyl groups by condensation with hydroxylamine hydrochloride; condensation with excess sodium cyanide, and estimation of the ammonia from the hydrolysis of the cyanohydrins, gave better results.Aldehyde groups in an oxystarch containing 0.16 M. of carboxyl and 0.14 M. of carbonyl groups were selectively oxidized with chlorous acid or alkaline hypoiodite, or were selectively condensed with sodium bisulphite solution. All three estimations indicated that about one-third of the carbonyl groups were aldehydes probably occupying the sixth positions in the glucose residues. The cyanohydrin of the oxystarch, when saponified and then hydrolyzed and reduced with boiling hydriodic acid, yielded the lactone of 2-methyl-4-hydroxyhexanoic acid, the recovery of which showed that at least 17% of the carbonyl groups occurred as 2-ketoglucose residues.

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