title: High accuracy pre-formed gradient discontinuous flow titrimetry.
abstract: A variant of Discontinuous Flow Analysis (DFA) titrimetry is described in which a pre-formed gradient is established between two titrant concentrations with the analyte aspirated at a constant rate into the gradient. The gradient encompasses a narrow range of analyte concentration (10% variation in this instance), and provides a high encoder pulse resolution. A simple acid-base titration model using photometric endpoint detection achieved comparable accuracy to conventional batch titrimetry (approximately 0.1% relative), with excellent calibration linearity (r(2) = 0.9997, standard error of estimation approximately 0.05% relative over six standards). Titrations were performed at the rate of one every 25 sec; with 0.8 ml of analyte and 0.85 ml of titrants consumed. The method is fully automatic.
authors.affiliation: Ionode Pty. Ltd., PO Box 52, Holland Park, Queensland 4121, Australia.
authors.forename: J D
authors.initials: JD
authors.lastname: Petty
authors.forename: D A
authors.initials: DA
authors.lastname: Petty
authors.forename: R M
authors.initials: RM
authors.lastname: Peachey
authors.forename: T K
authors.initials: TK
authors.lastname: Smith
authors.forename: B L
authors.initials: BL
authors.lastname: Krieger