title: Use of the ASTED system to determine L-NG-monomethylarginine (546C88) in human plasma by pre-column o-phthalaldehyde derivatisation and high-performance liquid chromatography.
abstract: The use of the system automated sequential trace enrichment of dialysates (ASTED), to prepare plasma samples for the estimation of L-NG-monomethylarginine (546C88) by pre-column o-phthalaldehyde-2-mercaptoethanol derivatisation and HPLC is described. Calibration is achieved using purified albumin as a substitute matrix for plasma. Using this technique the procedure was observed to be specific for 546C88 and linear over the range 0.10 to 50.0 mumol/l. The within-run imprecision (C.V.) at four different spiked plasma 546C88 concentrations of 0.10, 1.0, 8.0 and 40.0 mumol/l was 6.48, 2.55, 2.79 and 3.37%, respectively, and the between-run imprecision (C.V.) estimated to be 8.50, 1.80, 2.10 and 3.30%, respectively, for the same spiked 546C88 concentrations. The overall accuracy (% bias) of the procedure using an albumin matrix for calibration was estimated to be -2.50, -5.25, -3.56, -3.53%, respectively, and the recovery of 546C88 from six different spiked plasma samples estimated to be 99.1 +/- 1.4%.
authors.affiliation: Clinical Innovations Ltd., Kenilworth, Warwickshire, UK.
authors.forename: J D
authors.initials: JD
authors.lastname: Cooper
authors.forename: N
authors.initials: N
authors.lastname: Shearsby
authors.forename: C T
authors.initials: CT
authors.lastname: Sheung
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002940:Circadian Rhythm; D004791:Enzyme Inhibitors / Q000097:blood* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007202:Indicators and Reagents / Q000737:chemistry; D016014:Linear Models; D008623:Mercaptoethanol / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D009764:o-Phthalaldehyde / Q000737:chemistry*; D019323:omega-N-Methylarginine / Q000097:blood* / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D019323:omega-N-Methylarginine; D008623:Mercaptoethanol; D009764:o-Phthalaldehyde