Analysis of plasma amino acids by HPLC with photodiode array and fluorescence detection

Elisabeth L. Schwarz, William L. Roberts, Marzia Pasquali

Research output: Contribution to journalArticlepeer-review

131 Scopus citations


Background: Plasma amino acids are usually analyzed by ion-exchange chromatography (IEC), a reproducible but time consuming method. Here, we test whether plasma amino acids can be analyzed using reverse-phase high performance liquid chromatography (HPLC). Methods: Filtered plasma, with S-carboxymethyl-l-cysteine as the internal standard, was derivatized and analyzed by an Agilent 1100 HPLC system. Primary amino acids were derivatized with o-phthalaldehyde 3-mercaptopropionic acid (OPA) and detected by a diode array detector. Secondary amino acids were derivatized with 9-fluorenylmethyl chloroformate (FMOC) and detected fluorometrically. Chromatographic separation is achieved by two gradient elutions (two injections per sample), starting at different pHs, on a reverse phase Agilent Zorbax Eclipse C18 column AAA (4.6×150 mm). Results: The HPLC method evaluated correlated well with IEC (0.89≤r≤1.00) with linearity up to 2500 μmol/l. The between- and within-run CVs were
Original languageEnglish (US)
Pages (from-to)83-90
Number of pages8
JournalClinica Chimica Acta
Issue number1-2
StatePublished - Jan 1 2005
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical


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