Colorimetric Method for Ester Content of Alcoholic Beverages

1971 ◽  
Vol 54 (5) ◽  
pp. 1225-1230
Author(s):  
G R Coe ◽  
S Baldwin ◽  
A A Andreasen
Keyword(s):  
Alkaline Solution ◽  
Hydroxamic Acid ◽  
Colorimetric Method ◽  
Small Sample ◽  
Alcoholic Beverages ◽  
Colored Complex ◽  
Ester Content

Abstract A colorimetric method for determination of esters in alcoholic products was studied for the effect of procedural variables. It is based on the quantitative reaction of esters with hydroxylamine in alkaline solution to form a hydroxamic acid which, upon acidification, forms a colored complex in the presence of Fe(III) ions. Mathematical data are presented to demonstrate that the colorimetric method is superior to the AOAC saponification method, 9.051-9.052, for comparing samples which contain widely differing ester compositions. The colorimetric method is rapid and requires a small sample.

scholarly journals Changes of organic acids and phenolic compounds contents in grapevine berries during their ripening

2013 ◽  
Vol 11 (10) ◽  
pp. 1575-1582 ◽  
Author(s):  
Irena Jančářová ◽  
Luděk Jančář ◽  
Alice Náplavová ◽  
Vlastimil Kubáň
Keyword(s):  
Phenolic Compounds ◽  
Tartaric Acid ◽  
Alkaline Solution ◽  
Spectrophotometric Method ◽  
Total Content ◽  
Titratable Acidity ◽  
Colored Complex ◽  
Total Titratable Acidity ◽  
Phenolic Substances

AbstractChanges of total content of phenolic substances, alteration in total titratable acidity and differences in tartaric acid content in grapes of four white (Müller-Thurgau — MT, Pinot Blanc — Rulandské bílé in Czech, RB, Sauvignon (Sg), and Muscat Ottonel — Muškát Ottonel in Czech, MO) and two blue (Dornfelder — Df and Blue Frankish — Frankovka in Czech, Fr) grapevine varieties throughout their growth, ripening and maturing (July–November). Potentiometric titration was applied for the determination of total titratable acids in grapes (expressed as tartaric acid equivalents in g L−1). A spectrophotometric method according Rebelein based on the formation of a colored complex of ammonium metavanadate and tartaric acid was used for determination of tartaric acid in green juice made by pressing unripe grapes. A spectrophotometric method based on reduction of phosphomolybdato-tungsten complex in alkaline solution using Folin-Ciocalteau reagent was applied for determination of total content of phenolic substances (TCP).

A colorimetric method for the determination of hydroxamic acid by iodine oxidation

1985 ◽  
Vol 146 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Kyoichi Kobashi ◽  
Kazuo Sakaguchi ◽  
Sachiko Takebe ◽  
Kohei Hosaka
Keyword(s):  
Hydroxamic Acid ◽  
Colorimetric Method

Colorimetric Method for the Determination of Starch in Tobacco

1972 ◽  
Vol 55 (1) ◽  
pp. 209-213
Author(s):  
A J Sensabaugh ◽  
Kenneth L Rush
Keyword(s):  
Acid Treatment ◽  
Quantitative Measurement ◽  
Starch Content ◽  
Colorimetric Method ◽  
Colored Complex ◽  
Iodine Complex ◽  
Mesh Screen ◽  
Colorimetric Data ◽  
Tobacco Sample

Abstract A method is presented for extracting and determining the starch content of tobacco. Dried tobacco is ground to pass a 60 mesh screen, interfering colored materials are removed from the tobacco by a methanol-water extraction, and the starch is extracted from the tobacco by a perchloric acid treatment. Final quantitative measurement of the starch is made on a colored starch–iodine complex. The absorbance of this colored complex at 600 nm is proportional to the concentration of the starch in solution and can be related to the starch content of the original tobacco sample. Also included is a procedure for the isolation of pure tobacco starch. Such material was prepared for use as a calibration standard needed for the calculation of starch content of tobacco samples from the colorimetric data.

Comparison of GLC and Colorimetric Methods for Determination of Methanol in Alcoholic Beverages

1971 ◽  
Vol 54 (4) ◽  
pp. 785-786
Author(s):  
R H Dyer
Keyword(s):  
Colorimetric Method ◽  
Alcoholic Beverages ◽  
Methanol Content ◽  
Comparison Of Results ◽  
Colorimetric Methods

Abstract A comparison of results by a proposed GLC method and the present AOAC colorimetric method (9.071-9.074) for methanol in alcoholic beverages is presented. The GLC method utilizes a Carbowax 1500 on Chromosorb W column (similar to 9.063) for determination of methanol content at concentrations as low as 0.003% methanol. In the lower methanol concentrations the GLC results were higher, possibly due to a loss of methanol during the distillation required for the colorimetric method. A total of 20 samples of various alcoholic beverages were analyzed for methanol and the concentration of methanol ranged from 0.004 to 0.37%.

Colorimetric Determination of 3-Amino-l,2,4-Triazole in Grain or Meal

1982 ◽  
Vol 65 (1) ◽  
pp. 24-27
Author(s):  
Michel Galoux ◽  
Jean-C Van Damme ◽  
Albert Bernes
Keyword(s):  
Sulfuric Acid ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Colored Complex ◽  
Adsorption Desorption

Abstract This colorimetric method for the determination of 3-amino-l,2,4-triazole in grain or meal is a modification of the Storherr and Burke method. The herbicide is extracted from grain with methanol, and purified by adsorption-desorption on resin. The extract is cleaned by digestion with sulfuric acid and clarified with charcoal. The colored complex formed by coupling with N-(1-naphthyl)ethylenediammonium dichloride is measured spectrophotometrically at 455 nm. The limit of detection is 0.05 ppm.

scholarly journals Spectrophotometric quantification of dolutegravir based on redox reaction with Fe3+/1,10-phenanthroline

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Swathi Naraparaju ◽  
Durai Ananda Kumar Thirumoorthy ◽  
Sunitha Gurrala ◽  
Asra Jabeen ◽  
Pani Kumar D. Anumolu
Keyword(s):  
Redox Reaction ◽  
Quantitative Measurement ◽  
Colorimetric Method ◽  
Dosage Forms ◽  
Control Analysis ◽  
Colored Complex ◽  
Pharmaceutical Dosage Form ◽  
Pharmaceutical Dosage Forms ◽  
Quality Control Analysis

Abstract Background A simple and sensitive spectrophotometric method was developed for the quantitative measurement of dolutegravir in pure form and pharmaceutical formulation. The present method was based on redox reaction between dolutegravir and ferric chloride, which upon complexation with 1,10-phenanthroline formed an orange-colored complex that showed absorption maximum at 520.0 nm. Results The developed method obeyed linearity in the concentration range of 40.00–140.00 μg/mL. The method was also validated as per International Council for Harmonization guidelines and the results were within acceptance values. The validated method was employed for the determination of dolutegravir in pharmaceutical dosage form and the percentage assay value was found to be 102.5, which is in agreement with its label claimed. Conclusion The developed redox-based colorimetric method could be used in the routine quality control analysis of dolutegravir present in various pharmaceutical dosage forms.

Interlaboratory Comparison of the Official AOAC Ester Determination for Alcoholic Beverages with a Colorimetric Method

1965 ◽  
Vol 48 (6) ◽  
pp. 1126-1131
Author(s):  
E T Blessinger ◽  
E G Laroe ◽  
H A Conner
Keyword(s):  
Interlaboratory Comparison ◽  
Colorimetric Method ◽  
Alcoholic Beverages ◽  
Official Method ◽  
Colorimetric Determination ◽  
Ferric Ions ◽  
Colored Complex ◽  
Significant Difference ◽  
Aoac Method ◽  
Colorimetric Procedure

Abstract The official AOAC ester determination, 9.030, was compared with a colorimetric method for measuring the concentration of esters in Bourbon whisky. The colorimetric procedure involves the reaction of the esters with hydroxylamine to form hydroxamic acids, which are reacted with ferric ions to form a colored complex that can be measured colorimetrically. An analysis of variance shows that the colorimetric determination is more precise than the official method. There was no significant difference in the accuracy of the two methods. Since the colorimetric procedure does not involve a hydrolysis step, it requires less time than the AOAC method.

Determination of Piperazine in Feeds

1967 ◽  
Vol 50 (2) ◽  
pp. 268-273 ◽  
Author(s):  
M F Loucks ◽  
Leo Nauer
Keyword(s):  
Standard Deviation ◽  
Confidence Limit ◽  
Colorimetric Method ◽  
Alcoholic Solution ◽  
Critical Factors ◽  
Colored Complex ◽  
Collaborative Studies ◽  
Average Variation ◽  
The Mean

Abstract Collaborative studies were continued on a modification of the p-benzoquinone colorimetric method proposed by Cavett and Heotis for determining piperazine in feeds. Piperazine is extracted from the feed with water and then reacted with a buffered, hot, alcoholic solution of p-benzoquinone to form a colored complex. Absorbance is measured spectrophotometrically at 490 mμ. Control of the several critical factors, including pH of the solution and time and temperature for the reaction, is necessary. Results indicate a standard deviation (<r) of ± 0.012% and a 95% confidence limit ( 2 o-) of ± 0.024% with an average variation of ± 10%. The mean recovery was 97%. It is recommended that the method be adopted as official, first action

Determination of Iron in Alcoholic Beverages

1970 ◽  
Vol 53 (1) ◽  
pp. 12-16
Author(s):  
M K Meredith ◽  
Sidney Baldwin ◽  
A A Andreasen
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Atomic Absorption Spectrophotometry ◽  
Alcoholic Beverages ◽  
Wet Oxidation ◽  
Special Equipment ◽  
Oxidation Method ◽  
Trained Personnel

Abstract Results are presented for a collaborative study on the determination of ppm iron in alcoholic beverages, except beer, by the following methods: atomic absorption spectrophotometry, direct colorimetry using 2,4,6-tripyridyl-s-triazine (TPTZ) for alcoholic beverages other than brandy, and wet oxidation using sodium hypochlorite and hydrogen peroxide followed by color development with TPTZ for brandy only. When available, atomic absorption is the method of choice because of its speed and accuracy. The colorimetric method eliminates ashing, is relatively rapid, and does not require special equipment or highly trained personnel; however, it does not give accurate results for brandy. The wet oxidation method is satisfactory for brandy but requires more time, proper ventilation, and trained personnel. Results by these methods are accurate for routine determinations and it is recommended that the first two methods be adopted as official first action for the alcoholic products specified. Study on the wet oxidation method for products containing chelating agents and/or “complexed iron” should be continued.

Determination of Esters in Alcoholic Beverages

1972 ◽  
Vol 55 (3) ◽  
pp. 559-563
Author(s):  
G R Coe ◽  
S Baldwin ◽  
A A Andreasen
Keyword(s):  
Statistical Evaluation ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Alcoholic Beverages ◽  
Accuracy And Precision

Abstract Results are presented on a collaborative study comparing 2 methods for the determination of esters in distilled alcoholic beverages. A previously described colorimetric method was compared with the present official AOAC saponification method, 9.050–9.052. Statistical evaluation of the data shows that the 2 methods are comparable in accuracy and precision. The colorimetric method has been adopted as official first action as an alternative to 9.050–9.052 for the determination of esters in distilled alcoholic beverages.

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