title: Application of the Phenomenex EZ:faasttrade mark amino acid analysis kit for rapid gas-chromatographic determination of concentrations of plasma tryptophan and its brain uptake competitors.
abstract: The Phenomenex EZ:faast amino acid analysis kit is available for gas (GC) or liquid (LC) chromatographic analysis of amino acids (AA) using mass spectrometry (MS) and other GC detectors. We used it for rapid GC determination of plasma tryptophan, its brain uptake competitors (Val, Leu, Ile, Phe and Tyr) and many other amino acids. Based on solid-phase extraction, this fast method enables one person to process two plasma samples in 8-10 min and six samples in approximately 15 min up to GC injection and a 7-min GC run per plasma sample. Using a Perkin-Elmer Clarus 500 GC, a Total Chrome software, a flame-ionisation detector (FID) and norvaline as internal standard, we used this method to analyse approximately 1,000 plasma samples from normal subjects undergoing acute tryptophan depletion and loading tests. The limit of detection for most amino acids is 1 nmol/ml (1 microM) and in many cases less. With manual injection, coefficients of variation for the above six amino acids were 1.5-6.2% (intra-assay) and 3.8-9.7% (inter-assay). This simple, rapid and elegant method will be valuable to the amino acid analyst and researcher, as it can save much manpower time and meet urgent emergency requests and the demands of a high-throughput laboratory.
authors: The Cardiff School of Health Sciences, University of Wales Institute Cardiff (UWIC), Llandaff Campus, Western Avenue, Cardiff, CF5 2YB, Wales, UK. ABadawy@uwic.ac.uk
authors: A A-B
authors: AA
authors: Badawy
authors: C J
authors: CJ
authors: Morgan
authors: J A
authors: JA
authors: Turner
mesh_terms: D000596:Amino Acids / Q000097:blood* / Q000493:pharmacokinetics; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002849:Chromatography, Gas / Q000379:methods / Q000592:standards; D005260:Female; D005470:Fluorometry / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D016014:Linear Models; D008297:Male; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D013997:Time Factors; D014364:Tryptophan / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic; D014364:Tryptophan