Amino acids flow-injection analysis

Progress has been made in developing electrochemical methods for detection of amino acids without derivatization.74 75 Evaporative light scattering (ELSD) is also a promising detection method.76 Flow-injection analysis... 

Many enzymatic assays have also been developed for the analysis of proteolytic products. Total amino acids in Cheddar cheese were determined by Puchades et al. (1990) using the L-amino acid oxidase enzyme. Glutamic acid has been quantified by flow injection analysis using glutamate dehydrogenase (Puchades et al., 1989) and using the Boehringer-Mannheim kit (McSweeney et al., 1993). 

Puchades, R., Lemieux, L., and Simard, R. E. (1990). Determination of free amino acids in cheese by flow injection analysis with an enzyme reactor and chemiluminescence detector.. Food Sci. 55,1555-1558. 

McCooeye, M., and Mester, Z. (2006). Comparison of flow injection analysis electrospray mass spectrometry and tandem mass spectrometry and electrospray high-field asymmetric waveform ion mobility mass spectrometry and tandem mass spectrometry for the determination of underivatized amino acids. Rapid Commun. Mass Spectrom. 20 1801-1808. 

Aspartame has been assayed by a flow injection analysis biosensor employing an immobilized enzyme (pronase) which cleaves the peptide bond. The resulting phenylalanine methyl ester is then detected by an L-amino acid oxidase electrode. This method was applied to analysis of aspartame in foods [82]. 

Flow-injection analysis (FIA) is a technique for automating chemical analyses. The principles of FIA are reviewed here. Methods for applying FIA to the anayses of nitrate, nitrite, phosphate, silicate, and total amino acids in seawater are examined. Analyses of other nutrients, metals, and carbonate system components are also discussed. Various techniques to eliminate the refractive index effect are reviewed. Finally, several examples of the application of FIA to oceanographic problems are presented. 

J.C. Cooper, J. Danzer, H.-L. Schmidt, Enhanced selectivity in flow-injection analysis for L-aminoacids using electrodialysis with amino acid oxidation, Anal. Chim. Acta 282 (1993) 369. 

J.L. Burguera, M. Burguera, M. de la Guardia, A. Salvador, Pyrolysis-flow-injection analysis-spectrophotometric determination of amino acids in aqueous solutions, Anal. Chim. Acta 261 (1992) 23. 

T. Hara, M. Toriyama, T. Ebuchi, and M. Imaki, Flow Injection Analysis of a-Amino Acids by the Chemiluminescence Method. Chem. Lett., 3 (1985) 341. 

T. Imato, C. Azemori, Y. Asano, and N. Ishibashi, Flow Injection Analysis of Organic Acids and Amino Acids in Sake (Japanese Rice Wine) by Using pH-Sensitive Glass Electrode and Acid-Base Buffer Solution [in Japanese]. J. Flow Injection Anal., 3(2) (1986) 103. 

One of the few reported uses of fiber-optic biosensors in food analysis in combination with flow injection analysis is the determination of L-glutamate in soups and sauces. This amino acid plays a central role in the oxidative determination of other amino acids and is capable of sensitizing gustatory nerves. Although glutamate occurs naturally in some foods, it is also used as a flavor enhancer. The biosensor was... 

See alsa Amperometry. Carbohydrates Sugars -Chromatographic Methods. Derivatization of Analytes. Electrophoresis Principles. Flow Injection Analysis Principles. Ion Exchange Principles. Liquid Chromatography Column Technology Chiral Analysis of Amino Acids. Sensors Amperometric Oxygen Sensors. 

An amperometric sensor for amino acids based on flow injection analysis (FIA) and using microelectrodes (10 pm diameter) primarily of P(Py) doped with sulfonate dopants such as tosylate and 3-sulfobenzoate was demonstrated by Akhtar et al. [823, 824]. Linear response was demonstrated for analytes such as aspartic acid and glutamic acid over the concentration range 7.5 X 10 to lO" with sensitivities in the region of 1.5 nC-M and detection limits of ca. 10 M. These authors also showed the use of a pattern recognition technique using the responses of six detector electrodes. Fig. 17-11 shows typical response of one of their sensors. 

Figure 5.19 Formation of amino acids on ice surfaces irradiated in the laboratory (Nature Nature 416, 403-406 (28 March 2002) doi 10.1038/416403a-permission granted). Data were obtained from analysis of the room temperature residue of photoprocessed interstellar medium ice analogue taken after 6 M HCl hydrolysis and derivatization (ECEE derivatives, Varian-Chrompack Chirasil-L-Val capillary column 12 m x 0.25 mm inner diameter, layer thickness 0.12 pirn splitless injection, 1.5 ml min-1 constant flow of He carrier gas oven temperature programmed for 3 min at 70°C, 5°C min-1, and 17.5 min at 180°C detection of total ion current with GC-MSD system Agilent 6890/5973). The inset shows the determination of alanine enantiomers in the above sample (Chirasil-L-Val 25 m, single ion monitoring for Ala-ECEE base peak at 116 a.m.u.). DAP, diaminopentanoic acid DAH, diaminohexanoic acid a.m.u., atomic mass units.

HPLC analysis of furosine (-peak II) in hydrolyzates of non-exposed- (bottom), buffer-exposed (middle), and glucose-exposed (top) dentin samples. Dentin was not reduced prior to hydrolysis. Only the relevant parts of the chromatograms are shown. Amino acids are visualized after post-column labelling with a fluorescent dye. I lysine, II furosine. III homoarginine (internal standard). Column Merck Polyspher AA-NA 120 x 4.6 mm flow 0.2 ml/min gradient pH 5.0 -10.2 postcolumn reagent 0.2 ml/min fluorescence Xgx 330 nm, 440 nm 100-yl injections in buffer pH 2. 

Pyrolysis was implemented in flow analysis in 1992 for the spectrophotometric determination of amino acids [312], The sample was injected... 

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