Precolumn Phenylisothiocyanate Derivatization and Liquid Chromatography of Amino Acids in Food

1989 ◽  
Vol 72 (6) ◽  
pp. 912-916 ◽  
Author(s):  
Steven R Hagen ◽  
Beverly Frost ◽  
Jorg Augustin
Keyword(s):  
Amino Acids ◽  
Liquid Chromatography ◽  
Food Item ◽  
Food Samples ◽  
Protein Hydrolysates ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Coefficients Of Variation

Abstract A precolumn phenylisothiocyanate derivatization method is described for the determination of amino acids in protein hydrolysates from a wide variety of complex food matrixes, with and without performic acid oxidation pretreatment. Analysis of samples that were not pretreated with performic acid was necessary since this pretreatment destroyed an average of 25% of the histidine and 87% of the tyrosine present in the food samples. This method is rapid and reproducible; coefficients of variation between duplicate analyses of the same food item were less than 5% for a majority of the amino acids. Occasionally, variation between duplicate analyses for histidine and tyrosine was greater than 10%. Recoveries of amino acids added to samples were in the 100% range.

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

1967 ◽  
Vol 45 (13) ◽  
pp. 1405-1410 ◽  
Author(s):  
John D. Castell ◽  
R. G. Ackman
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Unsaturated Fatty Acids ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Gas Liquid Chromatography ◽  
Positional Isomers ◽  
Flame Ionization ◽  
Hydrogen Flame

The total acidic products from the performic acid oxidation of the ozonide of methyl oleate formed in methanol may be esterified directly in a few hours with 2,2-dimethoxypropane. The ester concentrations are adequate for the determination of the positional isomers of monoethylenic fatty acids directly from the reaction mixture, using a hydrogen flame ionization gas–liquid chromatography detector. Dimethyl sulfoxide was not required to prevent the breakdown of 2,2-dimethoxypropane under the conditions employed.

Oxidation and Hydrolysis Determination of Sulfur Amino Acids in Food and Feed Ingredients: Collaborative Study

1985 ◽  
Vol 68 (5) ◽  
pp. 826-829 ◽  
Author(s):  
John L Macdonald ◽  
Mark W Krueger ◽  
John H Keller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Feed Ingredients ◽  
Methionine Sulfone ◽  
Coefficients Of Variation ◽  
Food And Feed ◽  
The Mean

Abstract Samples of 6 food and feed ingredients and a purified protein, plactoglobulin, were analyzed by 7 laboratories to determine the concentrations of cysteine as cysteic acid and methionine as methionine sulfone. Samples were oxidized by reaction with performic acid before hydrolysis with 6N HC1. The free amino acids were then separated and measured by ion-exchange chromatography on dedicated amino acid analyzers. Each laboratory was provided with a detailed method as well as sealed vials containing solutions of standards. For the determination of cysteine as cysteic acid, the coefficients of variation between laboratories for duplicate samples ranged from 7.13 to 10.8% for the 6 ingredients. For the determination of methionine as methionine sulfone, the coefficients of variation between laboratories for duplicate samples ranged from 1.18 to 12.8% for the 6 ingredients. Cysteine and methionine recoveries were determined by analysis of β-Iactoglobulin and were based on expected levels of each amino acid from amino acid sequence data. The mean recovery of cysteine was 95% with a range of 91-101%. The mean recovery of methionine was 101% with a range of 98-106%. This method has been adopted official first action.

Amino Acid Analysis of Feedstuff Hydrolysates by Cation Exchange High Performance Liquid Chromatography

1985 ◽  
Vol 68 (5) ◽  
pp. 1028-1032
Author(s):  
Robert G Elkin ◽  
Joseph E Griffith
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Amino Acid ◽  
Cation Exchange ◽  
High Performance ◽  
Peanut Meal ◽  
Performic Acid ◽  
Coefficients Of Variation ◽  
Peak Areas

Abstract Corn, peanut meal, and soybean meal samples were either untreated or oxidized with performic acid before hydrolysis; the amino acids were determined by cation exchange high performance liquid chromatography (LC) and conventional cation exchange LC using an amino acid analyzer (AAA). Reproducibility of each procedure was assessed by repeated injections of the same calibration standard solution over a period of several days. LC data were more precise with regard to coefficients of variation for amino acid retention times, but were more variable with regard to peak areas. Although some significant differences between methods were noted, feedstuff amino acid values obtained by LC and AAA compared very well. The only consistent differences observed within each feedstuff were that Phe and Tyr values were significantly lower when analyzed by LC compared with AAA. Results of this study suggest that modular LC instrumentation can be used to accurately and reproducibly analyze amino acids in feedstuff hydrolysates. Advantages of using ninhydrin derivatization for feedstuff analysis, as opposed to using o-phthalaldehyde or dansyl chloride, are discussed

Determination of Amino Acids in Feeds: Collaborative Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1362-1402 ◽  
Author(s):  
Cynthia R Llames ◽  
Johannes Fontaine
Keyword(s):  
Amino Acids ◽  
Acid Hydrolysis ◽  
Hydrobromic Acid ◽  
Collaborative Study ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Sodium Metabisulfite ◽  
Hydrolysis Method ◽  
Relative Standard

Abstract A total of 28 laboratories (including authors’ laboratories) participated in a collaborative study for determination of amino acids in feeds using 3 complementary procedures. Each collaborator analyzed 5 blind duplicate samples of feed and ingredients used in the poultry industry. The amount of amino acids in these materials ranged from 0.10 to 8.50%. Twenty-three laboratories conducted analyses using performic acid oxidation with acid hydrolysis—sodium metabisulfite method, 16 laboratories performed analyses using performic acid oxidation with acid hydrolysis—hydrobromic acid method, and 15 laboratories used acid hydrolysis method. The repeatability relative standard deviation values for all amino acids for all 3 procedures ranged from 1.1 to 5.6% for broiler finisher feed, 1.1 to 4.73% for starter feed, 1.3 to 9.6% for corn, 0.8 to 3.96% for fishmeal, and 0.8 to 12.7% for poultry meal. The reproducibility relative standard deviation values for all amino acids ranged from 3.71 to 19.80% for broiler finisher feed, 4.1 to 16.93% for starter feed, 4.4 to 28.2% for corn, 3.46 to 18.96% for fishmeal, and 3.73 to 24.1% for poultry meal. The performic acid oxidation with acid hydrolysis—sodium metabisulfite and hydrobromic acid methods, and acid hydrolysis method for determination of amino acids in feeds have been adopted first action by AOAC INTERNATIONAL.

Quantitative Analysis of Cystine, Methionine, Lysine, and Nine Other Amino Acids by a Single Oxidation-4 Hour Hydrolysis Method

1987 ◽  
Vol 70 (1) ◽  
pp. 171-174 ◽  
Author(s):  
Charles W Gehrke ◽  
Paul R Rexroad ◽  
Robert M Schisla ◽  
Joseph S Absheer ◽  
Robert W Zumwalt
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Content ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Hydrolysis Method ◽  
Methionine Sulfone ◽  
Limiting Amino Acid ◽  
Hydrolysis Of

Abstract The sulfur-containing amino acids cystine and methionine play important roles in animal, especially avian, nutrition. Because these ndror-containing amino acids are destroyed to varying extents by 6N HC1 hydrolysis, oxidation and hydrolysis of cystine to cysteic add and methionine to methionine sulfone have been widely used for determination of cystine and methionine. Lysine is considered the next limiting amino acid after the sulfur amino acids in poultry •ntrition; therefore, determination of the amino acid content of rations focuses first on these 3 amino acids. The objective of this investigation was to establish whether lysine and other amino acids could be accurately determined in proteinaceous materials which had mdergone performic acid oxidation. To perform this evaluation, lysine was determined in a variety of protein-containing materials both with and without performic acid oxidation. Performic acid oxidation followed by 6N HC1 hydrolysis at 145°C for 4 h allows accurate measurement of 3 amino acids especially important to poultry nutrition, cystine, methionine, and lysine, in a single preoxidized hydralysate; this method can be extended to another 9 protein amino adds.

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