title: Quantitation of tryptophan and other plasma amino acids by automated pre-column o-phthaldialdehyde derivatization high-performance liquid chromatography: improved sample preparation.
abstract: Pre-column derivatization with o-phthaldialdehyde is a rapid and sensitive method for the quantitation of amino acids in biological fluids. This method uses acetonitrile as a deproteinizing reagent which gives improved recovery of tryptophan compared with 5-sulfosalicylic acid and permits the measurement of aspartic acid which coelutes with 5-sulfosalicylic acid. The method is automated to increase reproducibility and convenience. Mean coefficients of variation for peak areas relative to internal standard were 3.2 and 5.2% for amino acid standards and plasma samples, respectively. The presence of nitrilotriacetic acid stabilized the o-phthaldialdehyde reagent which is important in an automated system. The method is suitable for the analysis of large numbers of plasma samples where total tryptophan and aspartic acid are of interest.
authors.affiliation: Department of Human Nutrition, Deakin University, Geelong, Australia.
authors.forename: A M
authors.initials: AM
authors.lastname: Uhe
authors.forename: G R
authors.initials: GR
authors.lastname: Collier
authors.forename: E A
authors.initials: EA
authors.lastname: McLennan
authors.forename: D J
authors.initials: DJ
authors.lastname: Tucker
authors.forename: K
authors.initials: K
authors.lastname: O'Dea
mesh_terms: D000097:Acetonitriles; D000596:Amino Acids / Q000097:blood*; D001322:Autoanalysis; D001557:Benzenesulfonates; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007202:Indicators and Reagents; D009571:Nitrilotriacetic Acid; D012016:Reference Values; D012459:Salicylates; D012709:Serum Albumin / Q000378:metabolism; D014238:Trichloroacetic Acid; D014364:Tryptophan / Q000097:blood*; D009764:o-Phthalaldehyde
chemical_list: D000097:Acetonitriles; D000596:Amino Acids; D001557:Benzenesulfonates; D007202:Indicators and Reagents; D012459:Salicylates; D012709:Serum Albumin; D014238:Trichloroacetic Acid; D009764:o-Phthalaldehyde; D014364:Tryptophan; D009571:Nitrilotriacetic Acid; C003366:sulfosalicylic acid; C032159:acetonitrile