title: Determination of amino acids in human plasma by liquid chromatography with postcolumn ninhydrin derivatization using a hydroxyapatite cartridge for precolumn deproteination.
abstract: Amino acids in human plasma were determined by liquid chromatography with postcolumn ninhydrin derivatization using a hydroxyapatite cartridge for precolumn deproteination. S-Carboxymethyl-L-cysteine, D-phenylglycine and S-aminoethyl-L-cysteine were found to be suitable internal standards. The proposed method is simple, rapid (deproteination time less than 1 min) and reproducible [relative standard deviation below 3% except for low-level aspartic acid (n = 3)]. The average recovery of 25 amino acids was above 90%. The elution time of amino acids in human plasma was approximately 2 h. Protein binding of tryptophan was also determined by the proposed method. The analytical data for amino acids in human plasma deproteinated using the proposed and published methods (5-sulphosalicylic acid and ethanol) were compared.
authors.affiliation: Ajinomoto Co., Central Research Laboratories, Kawasaki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Iwase
authors.forename: S
authors.initials: S
authors.lastname: Ozawa
authors.forename: M
authors.initials: M
authors.lastname: Ikuta
authors.forename: I
authors.initials: I
authors.lastname: Ono
mesh_terms: D000596:Amino Acids / Q000097:blood*; D002233:Carbocysteine; D011232:Chemical Precipitation; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D003545:Cysteine / Q000031:analogs & derivatives; D017886:Durapatite; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009555:Ninhydrin; D012016:Reference Values; D012680:Sensitivity and Specificity; D012965:Sodium Chloride
chemical_list: D000596:Amino Acids; C000204:S-2-aminoethyl cysteine; D012965:Sodium Chloride; D002233:Carbocysteine; D017886:Durapatite; D009555:Ninhydrin; D003545:Cysteine