Determination of amino acids

C. Wang, E. Haitmut, G. Wang, L. Zhou, E. Bayer and P. Lu, Determination of amino acid enantiomers by two-column gas cliromatography with valveless column switching , J. Chromatogr. 262 352-359 (1983). 

The method described above is applicable to a wide range of samples for the determination of amino acids in different matrices. For example, the amino acid composition and distribution of single enantiomers has been determined in protein hydrolysates, orange juice (Fig. 7-11), yogurt and seawater [23]. 

Gravimetric, photometric, chromatographic, enzymatic, and microbiological methods for the determination of amino acids are reviewed and discussed. Marked advances have been made during the present decade in methods applicable to the determination of amino acids, and with the development of new analytical methods it should soon be possible to determine all the amino acids of biological importance with a degree of accuracy sufficient for practical as well as many theoretical purposes. 

The importance of Heinrich Ritthausen s fundamental studies, 1862 to 1899, on analytical procedures for the determination of amino acids in proteins has been emphasized in the biographical sketches which have been presented by Osborne (210), Vickery (289), and Chibnall (47). It is of particular interest to note here the prediction made by Ritt-hausen about 1870 that the amino acid composition would prove to be the most adequate basis for the characterization of proteins. Ritthausen and Kreusler (230) were the first, in 1871, to determine amino acids derived from proteins, and some of the values which they found for aspartic and glutamic acids are given in Table III (cited by Chibnall, 47, and Vickery, 286). 

The isotope dilution principle, first employed by Hevesy and Hobbie (133) in 1932 for the determination of lead in ores, was applied by Schoenheimer et al. (241) to the determination of amino acids. [Shemin and Foster (248) have reviewed this topic.] An N15-amino acid derivative was added to a protein hydrolyzate, a sample of the amino acid to be determined was isolated and purified, the excess N15 in this product was estimated with the mass spectrograph, and the grams of amino acid originally present were calculated from Equation 2. 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Block, R. J., and Bolling, D., Determination of Amino Acids in Proteins and Foods, Spring-... 

MS may be used to investigate all of these but by far the most common application of LC-MS is concerned with the determination of amino acid sequences. 

Amino acid or cDNA sequencing Determination of amino acid sequence. 

RPLC was used for the simultaneous determination of amino acids and amino sugars, including galactosamine and glucosamine, in glycopeptide analysis.124... 

Fung, Y.-S. and Mo, S.-Y., Determination of amino acids and proteins by dualelectrode detection in a flow system, Anal. Chem., 67, 1121, 1995. 

Albin, D. M., Wubben, J. E., and Gabert, V. M., Effect of hydrolysis time on the determination of amino acids in samples of soybean products with ion-exchange chromatography or precolumn derivatization with phenyl isothiocyanate,. Agr. Food Chem., 48, 1684, 2000. 

Vela, M., Saurina, J., and Hemandez-Cassou, S., Flow-injection spectrophoto-metric determination of amino acids by using l,2,-naphthoquinone-4-sul-fonate immobilized on an ion exchange resin, Anal. Lett., 31, 313, 1998. 

Arnold, U., Ludwig, E., Kuehn, R., Moeschwitzer, U., Analysis of free amino acids in green coffee beans, Part 1, Determination of amino acids after precolumn derivatization using 9-fluorenylmethylchloroformate, Z. Lebensm.-Forsch. 199(1), 22, 1994. (CA121 132515y)... 

M.P. Colombini, R. Fuoco, A. Giacomelli, B. Muscatello, Characterization of Proteinaceous Binders in Wall Painting Samples by Microwave Assisted Acid Hydrolysis and GC MS Determination of Amino Acids, Studies in Conservation, 43, 33 41 (1998). 

Pocklington R (1970) A new method for the determination of amino acids in sea water and an investigation of the dissolved free amino acids of North Atlantic Ocean waters. PhD Dissertation. Dalhousie University, pp 1-102... 

Mopper [265] has described developments in the reverse phase performance liquid chromatographic determination of amino acids in seawater. He describes the development of a simple, highly sensitive procedure based on the conversion of dissolved free amino acids to highly fluorescent, moderately hydrophobic isoindoles by a derivatisation reaction with excess o-phthalaldehyde and a thiol, directly in seawater. Reacted seawater samples were injected without further treatment into a reverse-phase high-performance liquid chromato-... 

Determination of Amino Acids Liberated in the Course of Total... 

Determination of Amino Acid Content of Certain Nitrogen Fractions... 

The improved methods introduced in the years 1940 to 1945 created new possibilities in this field. The Van Slyke method for quantitative determination of amino acids, based on the measurement of the volume of carbon dioxide evolved in the course of the reaction between amino acids and ninhydrin (V2), was much more reliable than the older methods. At the same time the microbiological methods designed for amino acid determinations (D3, S6) made possible the detection of very small concentrations of these compounds. The application of these... 

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